An Ecosystem Approach to Management of Seamounts in the ...project, these volumes were used as...

An Ecosystem Approach toManagement of Seamounts in the Southern Indian OceanVolume 2 – Anthropogenic Threats to Seamount

Ecosystems and BiodiversityEdited by François Simard and Aurélie Spadone

IUCN GLOBAL MARINE AND POLAR PROGRAMME

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Copyright: © 2012 International Union for Conservation of Nature and Natural Resources

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Citation: Simard F., Spadone A. (eds) (2012). An Ecosystem Approach to Management ofSeamounts in the Southern Indian Ocean. Volume 2 – Anthropogenic Theats toSeamount Ecosystems and Biodiversity. Gland, Switzerland: IUCN. iv+64 pp.

This paper is to be read in conjunction with two others: one giving an overview ofseamount ecosystems and biodiversity (Volume 1) and one on a legal and instituionalgap analysis (Volume 3).

ISBN: 978-2-8317-1563-6

Cover photos: Front: Trawler in the South West Indian Ocean, © Leigthon RolleyBack: Sunset in the South West Indian Ocean, © IUCN/Aurélie Spadone

Layout by: Tim Davis, DJEnvironmental, UK

Available from: IUCN (International Union for Conservation of Nature)Publications ServicesRue Mauverney 281196 GlandSwitzerlandTel +41 22 999 0000Fax +41 22 999 [email protected]/publications

IUCN SIO Seamount Governance i

An Ecosystem Approach toManagement of Seamounts in the Southern Indian OceanVolume 2 – Anthropogenic Threats to Seamount

Ecosystems and BiodiversityEdited by François Simard and Aurélie Spadone

Foreword.........................................................................................................................................vi

Executive Summary ........................................................................................................................1

CHAPTER 1 – NON-FISHERIES THREATS – by Philomène Verlaan .............................................3

I. Introduction................................................................................................................................3A. Background ..........................................................................................................................3B. Purpose of the paper ............................................................................................................3C. Scope of the paper ...............................................................................................................3D. Ecosystems and biodiversity – context ..................................................................................4E. Approach ..............................................................................................................................4F. Acknowledgement of sources and references .......................................................................5

II. Threats and Effects ...................................................................................................................6A. Threats from activities common to all ships ...........................................................................6

1. Accidental and/or deliberate (operational) discharges from vessels of: ............................6a. Anti-foulants..............................................................................................................6b. Bilge water, ballast water and associated sediments .................................................6c. Cargo........................................................................................................................7d. Chemicals and other harmful commercial products and substances .........................8e. Exhaust and other gaseous emissions ......................................................................8f. Garbage....................................................................................................................9g. Heavy metals ............................................................................................................9h. Oil ...........................................................................................................................10i. Persistent organic pollutants (POPs)........................................................................12j. Sewage...................................................................................................................12

2. Anchoring .....................................................................................................................133. Collisions (ship strikes) with, e.g., marine mammals, sharks, turtles...............................134. Grounding and shipwreck.............................................................................................135. Invasive alien species (IAS)............................................................................................146. Noise............................................................................................................................157. Shading and lighting .....................................................................................................178. Washes and wakes.......................................................................................................17

B. Activities for which the ship serves primarily as a platform ...................................................181. Archaeology .................................................................................................................182. Artificial islands and fixed/floating installations ...............................................................193. Bioprospecting .............................................................................................................194. Dumping.......................................................................................................................195. Marine mining ...............................................................................................................20

a. Minerals – fuel .........................................................................................................20i. Oil and gas ........................................................................................................20ii. Methane hydrates..............................................................................................21

b. Minerals – non-fuel ..................................................................................................21i. Ferro-manganese nodules and crusts................................................................21ii. Polymetallic sulphides........................................................................................22iii. Phosphorites, limestone, sand and gravel..........................................................23

6. Marine scientific research..............................................................................................23

TABLE OF CONTENTS

7. Military activities............................................................................................................248. Ocean-based climate-change mitigation.......................................................................249. Piracy/criminal activities ................................................................................................2610. Recreation ....................................................................................................................2611. Salvage ........................................................................................................................2612. Undersea cable- and pipeline-laying .............................................................................27

a. Cables ....................................................................................................................27b. Pipelines .................................................................................................................28

C. Threats from activities not involving ships ............................................................................281. Anthropogenic climate change......................................................................................282. Land-based activities....................................................................................................293. Marine debris or litter ....................................................................................................294. Overflight ......................................................................................................................315. Radionucleides .............................................................................................................31

III. Knowledge Gaps ...................................................................................................................32

IV. Analytical Summary...............................................................................................................33

V. Conclusions ...........................................................................................................................35

VI. References .............................................................................................................................36

CHAPTER 2 – FISHERIES AND AQUACULTURE – by Garry Preston .........................................48

I. Fisheries...................................................................................................................................48A. Introduction.........................................................................................................................48B. Stock depletion ...................................................................................................................50C. Physical damage to benthic ecosystems.............................................................................50D. Target species and by-catch ...............................................................................................52E. Discards..............................................................................................................................53F. Ghost fishing .......................................................................................................................53G. Noise and acoustic devices.................................................................................................54H. Harvesting of genetically unique resources ..........................................................................54I. Deep-water corals...............................................................................................................55J. Marine aquarium trade ........................................................................................................55K. Sports/recreational fishing ...................................................................................................55

II. Aquaculture..............................................................................................................................56A. Introduction.........................................................................................................................56B. Feeding and waste disposal ................................................................................................57C. Disease ...............................................................................................................................57D. Escapes..............................................................................................................................59E. Endangered and sensitive species.......................................................................................59

III. Ocean Fertilization...................................................................................................................60

IV. References...............................................................................................................................61

V. Other Useful Sources ..............................................................................................................63

Abbreviations and Acronyms .......................................................................................................64

TABLE OF CONTENTS

iv

As part of the scientific component of the project,two research expeditions were conducted onseamounts of the South West Indian Ridge. Thefirst one, which took place in 2009 aboard theR/V Dr Fridtjof Nansen as part of the EAF-Nansenproject, studied the pelagic fauna (in the watercolumn) associated with seamounts, while thesecond expedition, aboard the RRS James Cook(funded by the Natural Environment ResearchCouncil, NERC) in 2011, focused on the benthicrealm (on the seafloor). By conducting some ofthe very first assessments of seamountecosystems, the project created a vital baselineon the environmental status of seamounts fromwhich future trends and impacts can bemonitored. One characteristic of deep-seaecosystems is the slow growth rate of the speciesassociated with them; it is likely that thesecommunities will recover only very slowly, if at all,from ecological damage such as overexploitationof marine resources or habitat destruction.

The ecosystems in ABNJ, including seamounts,are subject to negative impacts from humanactivities in many sectors. Whereas fishingactivities are widely recognized as the mostsignificant threat to these ecosystems, the threatsresulting from the complete range of humanactivities in these areas have to be taken intoaccount. The cumulative effects of those threatsshould be considered so as to be able to improvebiodiversity conservation and find ways towardssustainable management of marine ecosystems.

Chapter 1 (by Philomène Verlaan) of this volumepresents the overall context of anthropogenicthreats to seamount ecosystems and biodiversity,and examines the non-fisheries threats toseamount ecosystems in ABNJ. Chapter 2 (byGarry Preston) then goes on to describe thethreats from fisheries and aquaculture.

François Simard & Aurélie SpadoneIUCN Global Marine and Polar Programme

Disclaimer: Any opinions or views expressed inthe following chapters are those of the authorsand others cited therein as appropriate and do notimply any opinion or views whatsoever by or onthe part of IUCN.

Seamounts, underwater mountains risingfrom the seafloor, are abundant features ofthe world’s oceans and as such are one of

the most common oceanic ecosystems in theworld. Known to be hotspots of biological activityand diversity, seamounts are globally important formarine biodiversity and play a vital role in marinefood webs. Marine mammals, migratory fish andseabirds, for instance, are largely dependent onthem for food. To date, the limited understandingwe have of the marine fauna associated withseamounts indicates that many species grow andreproduce slowly and are thus highly vulnerable tooverexploitation. One of the main barriers tosustainable management of seamountecosystems and conservation of marinebiodiversity in the high seas is a lack ofknowledge about these fragile ecosystems.

Within the framework of its medium-size UNDP-GEF Seamounts project (‘Applying an ecosystem-based approach to fisheries management in thehigh seas: focus on Seamounts in the southernIndian Ocean’), IUCN has coordinated thecompilation of a paper examining existing andpotential future threats of human activities toseamount ecosystems and biodiversity located inAreas Beyond National Jurisdiction (ABNJ).

The present document is to be read inconjunction with two companion papers: anOverview of Seamount Ecosystems andBiodiversity (Volume 1, authored by Alex Rogers),and a Legal and Institutional Gap Analysis (Volume3, authored by Robin Warner, Philomène Verlaanand Gail Lugten). These three volumes – whichform the series ‘An Ecosystem Approach toManagement of Seamounts in the SouthernIndian Ocean’ – serve as a basis for thedevelopment of a road map towards thesustainable use and conservation of biodiversity inthe Southern Indian Ocean.

In addition to being major outcomes of theproject, these volumes were used as backgroundpapers for two important workshops: aGovernance workshop organized jointly with theASCLME Project in Rhodes University,Grahamstown, South Africa, in June 2011, and aManagement workshop that took place in Rome,Italy, in July 2012.

FOREWORD

The activities posing actual or potential threats toseamount biodiversity and ecosystems aregrouped into three categories. All activitiesphysically conducted here will involve ships.Activities common to the use of all ships (category1) are distinguished from activities for which theship serves primarily as a platform (category 2).Category 3 covers activities that do not involveships but that actually or potentially affectseamount biodiversity and ecosystems, includingland-based activities.

From an ecosystem-based standpoint, categories1 and 3 represent an underlying chronic set ofthreats, superimposed on which are acute, andpotentially chronic, threats from category 2. None of the activities operate in an otherwiseunstressed (threat- and effect-free) environment.Anthropogenic threats and their effects can andoften do interact, with cumulative and synergisticadverse consequences for seamount biodiversityand ecosystems. Therefore none of the activitiesshould be considered in isolation in assessing itsimplications for seamount biodiversity andecosystem health.

The threats to seamount biodiversity andecosystems fall into one or more of the followingfour overarching categories:

1. Pollution2. Habitat destruction, degradation and

fragmentation 3. Overexploitation4. Invasive alien species (IAS).

Although the detailed interaction – feedbackloops – among this quartet of fundamental threatsis poorly understood, they also usually overlap inand exacerbate their individual deleterious effectson seamount ecosystems and biodiversity. It ishighly likely that their detrimental effects are alsosynergistic and cumulative. The ultimate results ofpollution, overexploitation and IAS are to degrade,fragment and eventually destroy seamounthabitats, and thus their biodiversity and eco-systems on an oceanic, i.e., basin-wide, scale.

EXECUTIVE SUMMARY

SIO Seamounts – Anthropogenic Threats 1

The individual and cumulative threats to andeffects of the full range of human activitieson marine ecosystems and biodiversity in

general, and seamounts in particular, in areasbeyond national jurisdiction (ABNJ) are still largelyunknown. These threats and their effects must betaken into account in order to be able to developa robust, holistic ecosystem-based managementscheme. This paper compiles and examinesexisting and potential future threats to seamountecosystems and biodiversity located in ABNJ ofthe Indian Ocean. It is also intended to serve as atemplate for anthropogenic threat analyses ofother seamount ecosystems elsewhere. Hencethe scope of the present study includes actualand imminent threats to these areas as well. Aninstitutional and legal gap analysis complementsthis paper. The reader is referred to thiscompanion paper as appropriate.

Ecosystems and biodiversity must not beconflated. They play interactive but distinct roles inthe marine environment. Biodiversity is thefundamental component of ecosystems, and avariety of ecosystems is included in the conceptof biodiversity. Biodiversity provides options fororganisms to respond to environmentalchallenges – such as those posed by theactivities addressed in this paper – by maintainingtheir variability. To function best, biodiversityrequires healthy ecosystems and vice-versa.Maintenance of biodiversity is essential toecosystem stability. Loss of biodiversity cantemporarily or permanently move an ecosysteminto a different set of biogeochemical conditions,and lead to – at best – changes and – at worst –disruption of or reduction in the ecosystem'seffective operation.

Many different mechanisms and ecosystems areresponsible for the origin and maintenance ofdifferent aspects of biodiversity. They are allimportant to one or more species at one or morepoints in their life cycle. Marine ecosystems arenumerous and varied, they operate on severaltemporal and spatial scales, and they are allcrucial to marine biodiversity.

2 SIO Seamounts – Anthropogenic Threats

Ecosystem change in response to threats is oftenneither linear nor gradual. It tends to occurabruptly or accelerates once a threshold iscrossed. This threshold is called the tipping point.After the tipping point has occurred, recovery orrehabilitation of the ecosystem is virtuallyimpossible. Even if it were possible, it would beprohibitively expensive. The occurrence of tippingpoints in the marine environment is at presentunpredictable.

Seamount ecosystems are particularly fragile andvulnerable to anthropogenic threats. Anyadditional or new activity, or the intensification ofan ongoing activity, could become the tippingpoint for the collapse of a seamount ecosystem.At present an objective comparator of the threatsand effects associated with the activities in thisregard is lacking. This fundamental knowledgegap would be filled by a mechanism to improvethe predictability of the tipping point trigger(s) andto improve the quantification of the risks thereoffor seamount ecosystems.

EXECUTIVE SUMMARY

Inside a bluefin tuna cage. © Marco-Carè/Marine Photobank

B. Purpose of the paper

Fishing activities are widely recognized as themost significant threat to marine ecosystems andbiodiversity, including seamounts, in areas beyondnational jurisdiction (ABNJ), which include the highseas and the seabed beyond either 200 or up to~350 nautical miles (nm) (depending in the lattercase on the extent of the outer continental shelf).However, the individual and cumulative threats toand effects of the full range of human activities inABNJ in general and seamounts in particular arenot yet well characterized. These threats and theireffects must be taken into account in order to beable to develop a robust, holistic ecosystem-based management scheme. Therefore one ofthe planned activities under this project is thepreparation of a paper compiling and examiningexisting and potential future threats of humanactivities to seamount ecosystems andbiodiversity located in ABNJ.

C. Scope of the paper

Although the initial purpose of this paper is toaddress the requirements of the GEF SIO project,it is also intended to serve as a template foranthropogenic threat analyses of other seamountecosystems elsewhere. Hence the scope of thepresent study includes actual and imminentthreats to these areas as well as to the specificGEF SIO project area. It is hoped that this morecomprehensive approach will contribute to effortsunderway to develop regulatory mechanisms tointegrate and coordinate the environmentallyresponsible management of all human activities inABNJ. This paper complements anothercommissioned for the GEF SIO project: aninstitutional and legal gap analysis. The reader isreferred to this companion paper as appropriate.

This paper does not address the potential oractual (il)legality of the activities causing thethreats, or any regulatory mechanisms either inplace or proposed to deal with them. Nor does itpropose any such mechanisms. Insofar asinternational law, including treaty law, providesdefinitions for the concepts and activities

A. Background

The International Union for Conservation of Nature(IUCN) and its members have a long-standingcommitment to achieving effective protection,restoration and sustainable use of biologicaldiversity and ecosystem processes on the highseas. This commitment was reiterated at the2008 IUCN World Conservation Congress.Through Resolution 4.031 ‘Achieving conservationof marine biodiversity in areas beyond nationaljurisdiction’, IUCN members called, inter alia, forthe promotion of arrangements, processes andagreements that ensure the consistent,coordinated and coherent application of the bestconservation and governance principles andapproaches, including integrated ecosystem-based management and the precautionaryapproach.

As part of this mandate, IUCN, in partnership withthe United Nations Development Programme(UNDP), developed a medium-size project entitled‘Applying an ecosystem-based approach tofisheries management: focus on seamounts in thesouthern Indian Ocean’, which was approved bythe Global Environment Facility (GEF) in December2008. The overarching project objective is to helpimprove marine resources conservation andmanagement in the high seas. Biodiversity-richareas, centred on seamounts, of the southernIndian Ocean (SIO) have been chosen to serve asa test case. The GEF SIO project has four maincomponents:

1. Improve scientific understanding of seamountsin the SIO (two research expeditions, oneeach in 2009 and 2011);

2. Improve the governance framework (the mainactivity will be to undertake a legal gapanalysis for the Indian Ocean and proposeoptions for improvement);

3. Develop a model ecosystem-basedmanagement framework for the area; and

4. Communications and outreach.

I. INTRODUCTION


CHAPTER 1 – NON-FISHERIES THREATSAuthor: Philomène Verlaan

INTRODUCTION


considered here, it will be adduced only to invokethose definitions.

With regard to activities that are at present stillconsidered to be imminent, this paper does notaddress the likelihood of those activities and theirconcomitant threats materializing. The variablesrelevant to such an assessment are too susceptibleto unpredictable shifts in politics and economics. Finally, this paper does not address the merits ofthe activities; it concerns itself only with thepotential threats to seamount ecosystems andbiodiversity posed by these activities and theireffects. Whether the merits outweigh the threats isa different exercise, to which this paper hopes tocontribute one set of considerations to be bornein mind when that exercise is undertaken. Thispaper sets out to present a baseline againstwhich proposals for the coordinated managementof seamount ecosystems and biodiversity can bedeveloped and evaluated.

D. Ecosystems and biodiversity – context

Ecosystems and biodiversity must not beconflated. They play interactive but distinct roles inthe marine environment. The Convention onBiological Diversity (CBD) defines biodiversity as"the variability among living organisms from allsources including, inter alia, terrestrial, marine andother aquatic ecosystems and the ecologicalcomplexes of which they are part; this includesdiversity between species, among species and ofecosystems" (Art. 2). The CBD defines ecosystemas "a dynamic complex of plant, animal andmicro-organism communities and their non-livingenvironment interacting as a functional unit" (Art. 2).While not ideal, these definitions suffice forpresent purposes: for biodiversity it highlightsvariability, i.e., active change, and for ecosystemsit emphasizes dynamic interactions.

Biodiversity is the fundamental component ofecosystems, and a variety of ecosystems isincluded in the concept of biodiversity. Biodiversityprovides options for organisms to respond toenvironmental challenges – such as those posedby the activities addressed in this paper – bymaintaining their variability. To function best,biodiversity requires healthy ecosystems and vice-versa. Ecosystems too require biodiversity for their

constituent communities and their interactions tooperate effectively, which includes the ability forecosystems to respond constructively toenvironmental challenges and changes.Maintenance of biodiversity is essential toecosystem stability. Loss of biodiversity cantemporarily or permanently move an ecosysteminto a different set of biogeochemical conditions,and lead to – at best – changes and – at worst –disruption of or reduction in the optimal operationof the ecosystem.

Marine ecosystems can be broadly divided into'static', i.e., more or less fixed to or closelyassociated with a solid surface, and 'mobile', i.e.,found in the water-column as a functioning unitunattached to any fixed substrate. Seamountshost both types of ecosystems. Seamounts alsoserve as essential focal areas for maintenance ofhealthy biodiversity and of ecosystems that do notfall neatly within either of those two overarchingcategories or the static-vs.-mobile ecosystemdichotomy. These include areas where speciesaggregate to breed, spawn, feed, rest, seekrefuge, just normally live in large numbers (school),and migrate. They also include "ocean triad"areas, where physical processes combine to"enrich, concentrate and retain" (Wurtz, 2007)various species and communities. Most – if notall – of these seamount ecosystems not only havehighly localized species, they are also high inendemics, i.e., they have species found only atone restricted location.

It is becoming increasingly clear that manydifferent mechanisms and ecosystems arerequired for the origin and maintenance ofdifferent aspects of marine biodiversity. Theyoperate on several temporal and spatial scalesand are all important to one or more species atone or more points in their life cycle. All areessential for marine biodiversity.

E. Approach

To minimize overlap between the effects of thethreats and facilitate both the present analysis andthe eventual broader utility of this study, theactivities posing actual or potential threats toseamount biodiversity and ecosystems aregrouped into three categories.

be considered in isolation in assessing itspotential consequences for seamount biodiversityand ecosystem health. Thus, for example, thecompanion institutional and legal gap analysisshould consider the effects of these activities inlight of the three categories of threats analysedhere.

F. Acknowledgement of sources andreferences

I am indebted to all the authors listed in thereferences (Part VI). They have not, because ofthe particular requirements and constraints of thepresent paper, other than for direct quotes, beenindividually credited at the point(s) where theirwork has been referred to or their ideas invoked.Any errors in my interpretation of the excellent andextensive work listed in Part VI are entirely my own.

All activities physically conducted in and aroundseamounts will involve ships. Threats from andeffects of activities common to the use of all ships(category 1) are distinguished from those threatsand effects deriving from activities for which theship serves primarily as a platform (category 2).However, not all activities that actually orpotentially affect seamount biodiversity andecosystems involve ships. Category 3 coversthreats and effects from this last group, whichincludes land-based activities.

In taking an ecosystem-based view, the first andthird categories represent an underlying chronicset of threats, superimposed on which are theacute – and potentially chronic – threats from thesecond category. None of the activities operate inan otherwise unstressed (threat- and effect-free)environment. Hence, none of the activities should

INTRODUCTION


Trawler and seabirds interaction, Western Cape, South Africa. © LucyKemp/MarinePhotobank

Organic booster biocides, often based on coppermetal oxides, are now being used as alternativesto organotin compounds in antifouling products,after restrictions were imposed on TBT use.However, one of the most commonly usedbiocides, Irgarol 1051, is known to inhibitphotosynthesis and growth in marine algae at verylow concentrations, and adversely affect primaryproductivity. Evidence of their toxicity to other non-target organisms, including phytoplanktonand corals, is mounting, and these new anti-fouling compounds present an emerging threat to seamount biodiversity and ecosystems.

b. Bilge water, ballast water and associatedsediments

Bilge water is a combination of rain-water,seawater, waste matter and oil seeping into lowerinterior spaces below deck. Ballast water isusually coastal water taken on board a ship inport, to stabilize an unladen or a lightly ladenvessel during her voyage. Ballast water isdischarged and exchanged for cargo at thedestination port. Ballast water is used to maintainthe essential operational and safety parametersfor overall trim, stability, and hull integrity of theship. It is dangerous for a ship to be either too lowor too high in the water. Ballast water may becarried in either dedicated or ‘segregated’ ballasttanks, used exclusively for that purpose, or in thecargo tanks of tankers. Ballasting cargo tanks isnow less common and usually found only whenthe vessel is putting on extra ‘heavy ballast’ or‘storm ballast’ in order to deal with especiallyheavy seas. The principal difference betweenbilge water and ballast water is that ballast watercontains living organisms, whereas bilge waterdoes not, because it usually contains too manycontaminants. Bilge water represents a threatwhose effects are similar to those of liquidscontaminated with garbage, heavy metals, oil andoily wastes, persistent organic pollutants (POPs)and sewage (see also Section A (1) (d, f-i)).

Ballast water can contain sediment if it is takenonboard in water that contains suspendedsediment. The sediment settles on the bottom ofthe tanks and is physically shovelled over the sideof the ship directly into the ocean when the ballastwater is discharged. These sediments and ballastwater can contain a wide range of live marine and


II. THREATS AND EFFECTS

A. Threats from activities common to allships

1. Accidental and/or deliberate (operational)discharges from vessels of:

a. Anti-foulantsFouling involves small, sedentary, burrow-dwellingor clinging organisms, such as algae, barnacles,and molluscs adhering to surfaces immersed inseawater. Anti-foulants are comprised within theconcept of anti-fouling systems (AFS) underinternational law, which are defined in theInternational Convention on the Control of HarmfulAnti-fouling Systems on Ships (AFS Convention)as “a coating, paint, surface treatment, surface ordevice that is used on a ship to control or preventattachment of unwanted organisms”. Annex 1 tothe AFS Convention lists AFS to be prohibited orcontrolled, including organotin compounds andother anti-foulants that act as biocides, to beupdated as necessary. Anti-foulants leach into theseawater, where they persist and probablybioaccumulate, causing adverse immuneresponses, and neurotoxic and deleterious geneticeffects in non-target marine species, as well askilling them outright. Dissolved organotins andorganotins adsorbed onto particles also accumulatein sediments, where they can contaminate and betoxic to benthic organisms and, on resuspensionfrom the sediments into the water column, furthercontaminate the water column.

One of the most effective anti-foulants containsthe organotin tributylin (TBT), shown to causedeformations in oysters and sex changes(imposex) in whelks (see also Section A (1) (g) on heavy metals). Imposex is associated withreduced reproductive potential and alteredpopulation structure in several species. Imposexis even found on the high seas; its incidencethere is correlated with high-density shippinglanes. Bioaccumulating up the food chain, TBTreaches very high concentrations in top predators,such as dolphins, tuna and sharks. Described byDr Laurence Mee as "probably the most toxicsubstance ever introduced deliberately into themarine environment" (Mee and Fowler, 1991), TBTdegrades slowly (in sediments under oligotrophicwater, degradation can take up to 87 years) andeven its degradation products can harm a widerange of marine organisms.

can be 20 feet to 40 feet long and 8 feet high.Modern container ships stack much of their loadhigh on the open deck. Despite stringent loadingand fastening regulations, it is estimated that2,000-10,000 containers are lost overboard everyyear, usually during storms. Overall, fewerincidents of loss occur, but when one does, morecontainers are lost because ships are muchbigger and the load is stowed wider and higher. It can take only one container to break free, or tocollapse, to trigger a cascade of containers overthe side.

The length of time a container will float dependson the type of cargo, and the type, permeability,and durability of the container. Some containersand cargoes sink immediately, while others mayfloat for months or years. Empty freight containersare not watertight and will quickly sink. Containersfilled with lightweight, low-density and buoyantcargoes can float for years – even when holed andwaterlogged. A reefer may float until it is brokenup by sea state and wave action. A low-densitycargo may float until the doors are damaged andopened by sea action. While afloat, containerslost at sea may not be easily visible and couldconstitute a shipping hazard. Container and cargolosses are not systematically monitored.

The threats posed by and the effects of cargo onseamount biodiversity and ecosystems dependon the nature of the cargo. (See also discussionof cargo residues and cargoes containinghazardous substances under Section A (1) (d) onchemicals, and of spoilt cargo under Section A(1) (f) on garbage). The threats and effects ofsubstances and materials introduced deliberatelyor accidentally into the marine environmentdiscussed in this paper are unlikely to differsubstantially if the materials or substances findtheir way into the ocean as components of avessel's cargo lost overboard rather than bydirect discharge (or dumping). With regard tocontainers and other cargo assemblages thatremain afloat for long periods, they can alsoserve as vectors for IAS (see also Section A (5)).One positive effect is that floating containers andcargo provide oceanographers with usefulempirical information in their work on trackingglobal ocean currents.

estuarine flora and fauna. Their larvae, spores andjuveniles can survive the long distances they aretransported on board vessels. Ballast water andthe associated sediments are important vectorsfor the transfer around the world of harmfulaquatic organisms and pathogens, knowngenerally as invasive alien species (IAS) – seeSection A (5). Ballast water remains of thegreatest concern because of the huge quantity ofwater transported and the wide variety oforganisms carried.

The International Maritime Organization (IMO)states that "the problem of invasive species islargely due to the expanded trade and trafficvolume over the last few decades. The effects inmany areas of the world have been devastating.Quantitative data show the rate of bio-invasions iscontinuing to increase at an alarming rate, in manycases exponentially, and new areas are beinginvaded all the time. Volumes of seaborne tradecontinue overall to increase and the problem maynot yet have reached its peak. Examples includethe introduction of the European zebra mussel(Dreissena polymorpha) in the Great Lakesbetween Canada and the United States, resultingin expenses of billions of dollars for pollutioncontrol and cleaning of fouled underwaterstructures and waterpipes; and the introduction ofthe American comb jelly (Mnemiopsis leidyi) to theBlack and Azov Seas, causing the near extinctionof anchovy and sprat fisheries" (IMO, 2010).

The International Convention for the Control andManagement of Ships' Ballast Water andSediments sets out to "prevent, minimize andultimately eliminate" this transfer. Although it is notyet in force, guidelines for its implementation havealready been promulgated and are steadilygaining acceptance. At present, the primarydefence against IAS in all current ballast-waterregimes, both voluntary and regulatory, is therequirement for an open-ocean exchange ofballast water. This constitutes a threat if it occursnear seamounts. See also Section A (1) (5) onIAS.

c. Cargo

Of primary concern here is the accidental loss atsea of cargo, and particularly of containers, which

THREATS AND EFFECTS


d. Chemicals and other harmful commercialproducts and substances

Some 250,000 anthropogenic chemicals arepresent in the marine environment, and every yearnew chemicals are introduced to the market,whence many of them eventually enter the sea.These substances have properties or produceeffects that are environmentally hazardous, suchas flammability, acute and chronic toxicity,corrosivity, reactivity, bio-accumulative propensity,and resistance to degradation. They can killorganisms directly, but equally – if not more –detrimental in the long run is the undermining ofecosystem integrity due to the effects of chronicexposure of organisms to these chemicals, whichcan impair immune systems, cause cancer anddevelopmental problems, and reducereproductive success.

They fall under the category of ‘harmfulsubstances’ defined in Article 2 of the InternationalConvention for the Prevention of Pollution fromShips (MARPOL) as “any substance which, ifintroduced into the sea, is liable to create hazardsto human health, to harm living resources andmarine life, to damage amenities or to interferewith other legitimate uses of the sea, and includesany substance subject to control by the presentConvention”. They are governed by Annexes IIand III of MARPOL.

Within this group and governed by MARPOLAnnex II are also included three categories ofwastes: washings of tanks containing noxiousliquid substances (NLS); cargo residues of NLS;and dirty ballast. The term NLS encompasses anybulk liquid chemical that does not meet thedefinition for oil as defined in MARPOL Annex I(see Section A (1) (h) on oil) and includespetrochemicals, solvents, waxes, lubrication oiladditives, vegetable oils and animal fats. Of thesethree categories, washings of tanks containingNLS often occur, whereas cargo residues anddirty ballast occur rarely. Cargo residues usuallyconsist of a single NLS. Dirty ballast contains verylow concentrations of NLS, but as most chemicalships have segregated ballast tanks or double hullspaces, ballast water contaminated with NLS isvery rare (see also Section A (1) (b) on bilge waterand ballast water). NLS cargoes are categorizedby the International Bulk Chemical (IBC) Code in

terms of the degree of hazard each individualcargo poses to marine resources or humanhealth. According to this categorization, Annex IIprohibits, limits or permits the discharge into themarine environment of NLS substancesdepending on the degree of hazard to eithermarine resources, or human health, or amenities.See also, with regard to chemical munitions andradioactive waste, Section B (4) and (7) ondumping and military activities, respectively.

Even in the open sea, as with garbage, oil, POPsand sewage (see Section A (1) (f, h-j)respectively), when vessels congregate or passregularly or often through or over a particularbiologically diverse area, such as a seamount,even operational discharges of chemicals, letalone accidental spills, cannot be assumed to beenvironmentally benign. The risk to seamounts ofship-source chemical pollution is exacerbated byatmospheric deposition of chemicals; this airbornesource has been estimated at ~33% of chemicalinputs to the ocean. The surface micro-layer ofthe open ocean also concentrates pollutants,often many times higher than in the underlyingwater column. Larvae collect in the micro-layer,and they are more sensitive to pollutants thanadults.

e. Exhaust and other gaseous emissions Ship emissions include CO2*, hydro-chlorofluorocarbons (HCFCs), hydrofluorocarbons(HFCs)*, methane (CH4)*, nitrogen oxides (NOx)including N2O (nitrous oxide)*, ozone-depletingsubstances (e.g., halons, chlorofluorocarbons(CFCs)), particulate matter, perfluorocarbons(PFCs)*, sulphur hexafluoride (SF6)*, sulphuroxides (SOx) and volatile organic compounds(VOCs) such as industrial solvents. (The asterisk(*) identifies major greenhouse gases (GHGs)under the Kyoto Protocol, a supplement to theFramework Convention on Climate Change, aninternational treaty to regulate emissions ofGHGs). By 2020, emissions of SOx frominternational shipping are estimated to increase by42% and of NOx by 66%. At present, shipemissions are most evident in the northernhemisphere, where the majority of shipping trafficoccurs, especially along the main shipping lanes,and within 400 km of the coast, where about 70-80% of the emissions occur.

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original specifications, is no longer marketable andusually consists of agricultural products or rawmaterials from mining or quarrying. Unless it isconsidered to be garbage generated duringnormal ship operations, it is subject to the oceandumping rules (see Section B (4)).

The threats posed by and the effects of garbageand spoilt cargo on seamount biodiversity andecosystems depend on the nature of the cargo –see also discussion of cargo above under SectionA (1) (c) and of the threats and effects of the othersubstances and materials introduced deliberatelyor accidentally into the marine environmentdiscussed in this paper. The threats and effects ofthese materials and substances are unlikely todiffer significantly whether they find their way intothe ocean as spoilt or lost cargo or by directdischarge. Even in the open sea, as withchemicals, oil, POPs and sewage (see Section A(1) (d, h, i, j) respectively), when vessels regularlyor often congregate in or pass through or over aparticular biologically diverse area, such as aseamount, operational and accidental dischargesof garbage there cannot be assumed to beenvironmentally benign.

Garbage is also a subset of marine litter or marinedebris, which is addressed in Section C (3).Annex V of MARPOL also applies to plastic, thedisposal of which anywhere at sea is prohibited.Of the various garbage categories, plastic posesthe greatest danger to seamount biodiversity andecosystems (see Section C (3) on marine debris/litter for discussion of threats posed by plastics).

g. Heavy metals

The term 'heavy metal' is often usedinterchangeably with 'trace metal'. Althoughneither term is entirely descriptively or scientificallycorrect, both refer to a group of elements thatexhibit metallic properties, and include biologicallyessential and non-essential trace/heavy metals.All are potentially toxic to living organisms ifbiologically available (this depends on theirspeciation, which varies with the elementconcerned) at concentrations above a certainlevel, which varies depending on the organismsinvolved. The principal essential trace metals, inapproximate order of biological importance, arethe transition elements Fe>Mn>Zn>Cu>Co>Ni.

The type and volume of ship emissions aregoverned by engine age and type, weatherconditions, fuel quantity and type, ship operationalmode, and use of any emission reductiontechnology. Though not negligible, shippingaccounts for about 2% of CO2 production, whichis ~three to five times less CO2 than road and railtransport produce and between twenty and thirtytimes less than air transport produces intransporting one tonne of cargo over onekilometre. Annex VI of MARPOL addressesemissions to the air from ships.

Vessel emissions exacerbate climate changethrough CO2 and other GHG production,decrease ambient air quality and, by increasingcloudiness through sulphur aerosol production,can alter solar radiation energy. Chemicalreactions in the atmosphere can convertemissions of NOx and SOx into, respectively,nitric and sulphuric acids. This process can takeseveral days, during which these pollutants cantravel thousands of kilometres from their originalsources. Both NOx and SOx are more water-soluble than CO2 and thus contribute significantlyto increasing the acidity of rainwater. Where thisacid rain falls on the ocean, it exacerbates theocean acidification caused there by excessiveproduction of CO2 from a variety of mostlyanthropogenic, land-based sources. (See alsoSection C (1) on anthropogenic climate change,which addresses, inter alia, ocean acidification.)

f. GarbageAnnex V of the MARPOL Convention definesgarbage as including all kinds of food, domesticand operational waste, excluding fresh fish,generated during the normal operation of thevessel and liable to be disposed of continuouslyor periodically. Garbage also includes cargoresidues and cargo-associated wastes. Theguidelines to MARPOL Annex V provide furtherdetails on what constitutes garbage.

Discharge into the sea of spoilt cargo is anenvironmental problem, but spoilt cargo is notdefined in the relevant Conventions or theguidelines. Circular Letter 2074 of 20 July 1998by IMO (available at: www.imo.org) notes that itcould be described as cargo which has changedduring the voyage such that it no longer meets its

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Primary producers extract them from seawater,where they are soluble, and biologically available,as divalent cations. The most important non-essential elements in this context, for which – sofar – only properties toxic to marine organismshave been observed, include arsenic (As, ametalloid), cadmium (Cd), lead (Pb), mercury (Hg),and tin (Sn).

Marine ecosystems and biodiversity are especiallysusceptible to the harmful effects of heavy/tracemetals. Marine organisms are in close andprolonged contact with the soluble forms of themetals throughout the water column and in theinterstitial water of sediments. Once introducedinto the food web, these metals canbioaccumulate and biomagnify up the food chain,increasing the organism's exposure risk byingestion. They also accumulate in sediments,whence they can be resuspended, thereby re-entering and re-polluting the water column.

In marine organisms heavy metals can inhibitgrowth, cause disease, developmentalaberrations and death, change biochemical andphysiological functions and behaviour, impairimmune systems and adversely affectreproduction. Benthic and near-surface organisms

are likely to be most at risk, with larvae beingespecially vulnerable. Photosynthesis can beinhibited in phytoplankton. For the effects of tin(Sn) in particular, see also Section A (1) (a) above,on antifoulants (TBT). For heavy metals in general,see also under Section B (4) on ocean dumping,

h. Oil

This short word covers a large and complexgroup of harmful liquid, gaseous and solidhydrocarbon compounds, including polycyclicaromatic hydrocarbons (PAHs, the most toxic,whose toxicity also varies with the bioavailability ofthe different PAH species). This group isaddressed by MARPOL Annex I and includescrude oil, refined petroleum products (e.g.,gasoline, diesel fuel) and by-products, ships'bunkers, oily refuse, oil mixed in waste, and sixcategories of waste generated in ships’ enginerooms and cargo spaces, i.e., oily bilge water, oilyresidues (sludge), oily tank washings (slops), dirtyballast water, scale and sludge from tankercleaning, and oily mixtures containing chemicals. The first two of the latter six categories of oilywastes are found in all vessels; the next three arefound in cargo spaces of oil and oil producttankers, and all involve cargo residues. Oily tankwashings and recovered cargo residues (slops)

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Oil and gas tankers. © Wolcott Henry/Marine Photobank

Oil discharged into the sea adversely affects themarine environment and marine organismsthroughout the food web, from phytoplankton tomarine mammals. The specific effects of oil willvary, depending on the form(s) in which it entersthe ocean, the location of the discharge, and theweather conditions. For example, when oil floatson top of the sea, less light penetrates into thewater, limiting photosynthesis by phytoplankton,the base of the marine food web. Eggs, larvae,fish and invertebrates in the water column,especially near the surface, can also be adverselyaffected. Larvae are more vulnerable as they areless able to detect and avoid the oil than adult fishand invertebrates. Eggs floating just under the seasurface are particularly susceptible tocontamination.

Exposure to oil reduces the insulation of seabirdplumage and marine mammal fur, increasing theirvulnerability to temperature fluctuations andhypothermia. Birds become less buoyant andtheir flight is impaired, making it difficult orimpossible to forage and escape from predators.Oil ingestion in seabirds and marine mammals(e.g., through preening by birds, consumption ofcontaminated prey) can damage kidneys, alterliver function and irritate the digestive tract,leading to dehydration and metabolic andhormonal imbalances. Prolonged exposure to lowlevels of oil can adversely affect survival andreproduction of seabirds, marine turtles andmarine mammals.

Sub-lethal toxicity is a pernicious effect of oilcontamination; for example, PAHs appear toinduce genetic damage, even at environmentallylow concentrations. The water-soluble fraction ofPAHs accumulates in membrane lipids, where itdisrupts membrane-associated biochemical,physiological and immunological functions.Chronic exposure to oil pollutants can increaseproduction of free radicals, leading to oxidativestress. Impaired behavioural responses, such aslower feeding rates and delayed escapemanoeuvers, are also observed. These effectscan all lead to changes in vital functions that affectthe survival and ability to reproduce of theaffected organisms and culminate in damagingtheir populations, communities and eventually theecosystem as a whole.

are the most common of the six. The ‘dirty ballastwater’ category comes from the now almostextinct non-segregated ballast tankers, as well ason the very rare occasions when tankers musttake on additional ballast water to increase theirdraft in particularly severe weather (see alsoSection A (b) above on bilges and ballast water),and when tankers of a particular design conductoperations under certain established exceptionalconditions. The category ‘scale and sludge fromtanker cleaning’ arises from cleaning operationsprior to surveys or repairs. The sixth category, ‘oilymixtures containing chemicals’, arises either fromcleaning of engine room machinery and spaces,or from washing tanks for oil or for products withwater mixed with chemical substances. See alsoSection A (1) (b-d) above.

Although accidental discharges – usually in theform of oil spills from foundering or wreckedtankers – capture the most attention, they arerare. Operational discharges are the mostimportant chronic and continuous sources fromshipping of oil to the oceans. Illegal operationaldischarges are a worldwide problem, especiallyon the high seas, where surveillance anddetection are generally absent.

Oil can evaporate, dissolve, emulsify into smalldrops, and form tar balls. Made up of the heavyviscous fraction of the oil, tar balls float in the seaand drift with currents and tides. Dissolution of oilcompounds, particularly of PAHs, results in theirincorporation into water-soluble fractions, whichare taken up by marine organisms and constitutea primary source of toxic exposure, especially atlower levels of the food web. Bioaccumulation byfilter feeders and biomagnification up the foodchain intensifies the toxic effects of oil onorganisms that concentrate these contaminants intheir tissues or on their predators. The densest oilfractions can sink to the bottom and contaminatethe benthos and sediments.

Sediments can constitute a particularly long-livedsource of oil-based contaminants, and especiallyof PAHs, where their concentration can be 100times higher than in the overlying water column.They adsorb easily onto particles because of theirhydrophobicity, and in this form are even moreresistant to degradation than dissolved PAHs.

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Accidental oil spills and chronic discharges canadversely affect open-ocean oceanographicfeatures where biological activity is concentrated,such as seamounts, as well as convergencezones, gyres and eddies, which can concentratepollutants (see also Section C (3) on marinedebris/litter). As with chemicals, garbage, POPsand sewage (see Section A (1) (d, f, i, j)respectively), even in the open sea, when vesselscongregate regularly and often in a particularbiologically diverse area such as over aseamount, operational discharges there cannotbe assumed to be environmentally benign.

i. Persistent organic pollutants (POPs)

These are carbon-based (hence ‘organic’), semi-volatile, high-molecular-weight (especiallydangerous at >236 g/mol) and low-water-solublechemical substances that become widelydistributed throughout the marine environment, farfrom their point of origin, and then persist there formany years. For example, one POP (PFOS, seelist below) has shown no degradation under anyenvironmental condition tested. POPs resistdegradation and bioaccumulate, especially in fattytissue (a consequence of their high lipid solubility),where their concentrations can magnify throughthe food web up to 70,000 times backgroundlevels. POPs are frequently halogenated, usuallywith chlorine. The more chlorine groups a POPhas, the more resistant it is to degradation. Theytend to volatilize in hot regions and accumulate incold regions, where they condense and remain,exacerbating their noxious effects on these fragilemarine environments because degradationprocesses are slower at low temperatures. Deep-sea oceanic food webs may be contaminated byPOPs as well, as deduced from the presence ofbrominated flame retardants (BFRs) in spermwhales, which feed in deep offshore waters.

The Convention on Persistent Organic Pollutantsgoverns the following POPs, which are usuallydivided into the following three categories:

m Pesticides: aldrin, chlordane,dichlorodiphenyltrichloroethane (DDT),dieldrin, endrin, heptachlor,hexachlorobenzene, mirex, toxaphene,chlordecone, alpha hexachlorocyclohexane,

beta hexachlorocyclohexane, lindane,pentachlorobenzene;

m Industrial chemicals: hexachlorobenzene,polychlorinated biphenyls (PCBs),hexabromobiphenyl, hexabromodiphenyl etherand heptabromodiphenyl ether,pentachlorobenzene, perfluorooctane sulfonicacid (PFOS), its salts and perfluorooctanesulfonyl fluoride (PFOS-F), tetrabromodiphenylether and pentabromodiphenyl ether; and

m By-products: polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans(PCDD/PCDF), and by-products from the twoother categories.

They have acute and chronic toxic effects onmarine organisms. Fish, predatory birds andmarine mammals are high up the food chain andso absorb the greatest concentrations. Low PCBlevels have also been found in Mediterraneanloggerhead turtles (Caretta caretta), suggestingthat POPS may also affect at least one of the sixendangered species of marine turtle. In marinemammals, certain POPs (especially BFRs), onceabsorbed, may be passed from mother to youngthrough the placenta and milk. Specific adverseeffects of POPs can include cancer, allergies andhypersensitivity, damage to the central andperipheral nervous systems, reproductivedisorders, and disruption of the immune system.Some POPs are endocrine disrupters, which, byaltering the hormonal system, can damage thereproductive and immune systems of exposedindividuals and their offspring, as well as havedevelopmental and carcinogenic effects. Theycan kill organisms directly and undermineecosystem integrity. Although POPs are only asmall part of the approximately 250,000anthropogenic chemicals present in the marineenvironment, they add substantial stress toecosystems already compromised by otherpollutants. See also Section A (1) (d) above onchemicals and other harmful commercial productsand substances.

j. Sewage

The discharge of raw sewage into the sea cancreate a health hazard from pathogens in thesewage, lead to changes in local microbial, phyto-

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substrata, the especial vulnerability of seagrasscommunities to anchoring must not be forgotten,as some seamount summits may be sufficientlyshallow to permit their presence.

3. Collisions (ship strikes) with, e.g., marinemammals, sharks, turtles

Ship strikes are regularly reported from all theoceans. For the groups mentioned in thesubheading above in particular, all of which aremore or less endangered, ship strikes are asource not only of individual fatalities but also ofan increased threat to the species as a whole.Insofar as members of these groups are known tocongregate around seamounts, ship strikes thereexacerbate their precarious survival status, whichis already under stress from other threatsaddressed in this chapter (e.g., noise, pollutants,prey depletion) and in Chapter 2 on fisheries.Noise pollution (see also Section A (6)) may alsoincrease the propensity for members of thesegroups to collide with ships; the animals may notbe able to detect the noise of an approachingship due to masking by other noise, or todistinguish between ship noise and other noises.

4. Grounding and shipwreck

Grounding is a threat in shallow water and couldtherefore be a problem where seamount summitsare near the surface. Its effects are similar tothose described in Section A (2) above for

and zoo-plankton communities, cause localizedoxygen depletion (hypoxia) because of itselevated nutrient content (especially N and P), andbe visually unpleasant. If the hypoxic areaintersects the ocean floor, benthic organisms,especially less mobile ones, may die. It is stillgenerally considered that the open oceans arecapable of assimilating and dealing with rawsewage through natural bacterial action. Annex IVof MARPOL, which deals with sewage, prohibitsships from discharging sewage within a specifieddistance (usually 12 nm) from the nearest land,unless they have in operation an approvedtreatment plant. However, as with chemicals,garbage, oil and POPs (see Section A (1) (d, f, h,i), respectively), even in the open sea, whenvessels regularly or often congregate in or passthrough or over a particular biologically diversearea, such as over a seamount, disposal ofsewage there cannot be assumed to beenvironmentally benign.

2. Anchoring

Anchoring physically destroys and alters habitatand habitat structure on the seafloor and harms orkills sessile, fixed and less mobile organisms inthe anchor's path, through direct physicaldestruction by the anchor and its chain andthrough sediment clouds raised by anchoring thatcan smother such organisms nearby. If theseafloor is shallow enough, increased turbidityfrom the sediment clouds can reduce primaryproduction, with all the concomitant adverseeffects further up the food chain, for whichphytoplankton form the base. The type andmagnitude of the effects depend on size and typeof anchor and the length of chain used, andwhether the anchor and chain ‘crab’, i.e., movesideways in response to the vessel's movementunder differing wind and sea states. Crabbingexacerbates the adverse environmental effects onthe benthic communities and their habitatbecause a much larger area is affected.

Anchoring destroys both hard and soft substrata,and thereby the habitatof the organisms andcommunities that can only live in association withone or the other. Vulnerable hard substratainclude, in particular, coral and associatedecosystems. With regard to soft (sediment)

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Anchors physically destroy and alter seafloorhabitat. © Daniel Sasse/Marine Photobank

anchoring, namely to physically destroy habitatsand their communities. Propeller scarring andabrasion by ships' hulls of the habitat are shallow-water physical threats that are also included in thiscategory. Grounding is temporary, in that thevessel is able to free itself; however, the activitiesnecessary to free the vessel will usually furtherdestroy the benthic environment. Permanentgrounding is treated as a shipwreck, and isdiscussed below.

Shipwrecks occur worldwide and it is estimatedthat since 1914 more than 10,000 ships havesunk to the seafloor through war and accidents.The locations of many of the vessels lost at seaare not known, especially of military vessels duringWorld War II that were carrying radioactive or otherhazardous materials. Where their locations areknown, their propensity to be a source of, inparticular, radioactive, chemical and heavy metalpollution is usually not investigated (see alsoSection B (7) on military activities).

The nature, scale and duration of theenvironmental effects of shipwrecks, especially inthe deep sea and on seamounts, have not yetbeen extensively studied. Effects will to a certainextent vary with, and may be reasonablypredicted from, the type of ship, her size andcargo, and the depth and latitude of the wreck(e.g., tropical or temperate or polar seas).

A ship foundered on a seamount will likely be asource of oil and other pollutants described inSection A (1) (a-j) above, as well as potentially asource of IAS (see also Section A (5)). A wreckcan cause substantial benthic habitat andcommunity destruction similar to that describedfor anchoring (see Section A (2) above andgrounding in this sub-section). In the fullness oftime, however, when all the pollutants havedecayed, dissolved, become diluted or otherwiserendered harmless, and if IAS have notoverwhelmed the native community, a wreck mayend up serving as a useful source of hard – albeitdifferent from the original – substratum, essentiallybecoming an artificial reef. This can be a valuableecological contribution, because hard substrataare at a premium in the deep sea, wheresediments dominate, even on seamounts. Thehard substratum provided by the wreck, around

which a community can re-establish itself, offerspotential for reconstitution of the communityoriginally destroyed by the wreck.

Although not yet in force, the 2007 InternationalConvention on the Removal of Wrecks providesthe legal basis for States to remove, or haveremoved, shipwrecks that may have the potentialto adversely affect the marine environment, and tohold the ship owners responsible. Environmentalcriteria such as damage likely to result from therelease into the marine environment of cargo or oilare also included. 'Removal' is defined as anyform of prevention, mitigation or elimination of thehazard created by a wreck (Art. 1 (7)) and 'hazard'is defined as "any condition or threat that … mayreasonably be expected to result in major harmfulconsequences to the marine environment" (Art. 1(5)). The wreck will have to be disposed of in anenvironmentally responsible manner (see alsoSection B (11) on salvage). The Wreck RemovalConvention applies to stranded (i.e., grounded,see above) ships (Art. 4 (a)) and to ships that are"about, or may reasonably be expected, to sink orto strand, where effective measures to assist theship or any property in danger are not alreadybeing taken" (Art. 4 (d)).

5. Invasive alien species (IAS)

An alien species is "an organism, inclusive ofparts, gametes or propagules, that may surviveand subsequently reproduce, occurring outsideits known ... native range, as documented inscientific publications … [and] whose populationhas undergone an exponential growth stage andis rapidly extending its range" (Galil et al., 2008). Avector is "any living or non-living carrier thattransports living organisms intentionally orunintentionally" (ICES, 2005).

Ships are important IAS vectors. The variety ofmeans by which ships can spread IAS include:

m fouling on the outside of the hull;

m poorly maintained marine sanitation devices;

m water on decks;

m water in anchor lockers;

m lost cargo and cargo containers (see SectionA (1) (c) on cargo, above);

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plankton from crustacean communities to the IASctenophore (comb jelly) Mnemiopsis leidyi. Thischanged the fish communities feeding on theplankton, and eventually, together with pollutionand overfishing, caused the fisheries to collapse.

The effects of IAS are felt in the water column andon the seafloor, on both hard and soft substrata.Competition for space on hard substrata, alwaysat a premium in the sea, is a particular threat, towhich seamounts are likely to be especiallyvulnerable.

6. Noise

Noise, as a form of energy, can constitute marinepollution within the definition of pollution set by theUnited Nations Convention on the Law of the Sea(LOSC). Given the steadily growing increase inanthropogenic noise levels in the ocean and theobserved adverse effects on marine organisms,noise probably already meets the LOSC's criteriafor pollution (see Part IV, Analytical Summary).

Anthropogenic noise in the ocean derives fromactivities such as:

m shipping (propellers, engines, machinery, andwater flow over the hull of ships);

m oil and gas exploration (explosives, drilling,seismic air guns) and exploitation (drillingplatforms);

m scientific research (sonar, seismic air guns,drill ships);

m military operations (sonar, weapons testing,explosives);

m offshore construction of facilities and theiroperation;

m dredging to lay pipelines and maintainshipping lanes; and

m acoustic deterrence and harassment devices.

These devices are so far most often used in afisheries context and are probably the principalexample of deliberate marine noise pollution. Theyare targeted at marine mammals but alsoadversely affect non-target species.

In some ocean basins, such as the North Atlantic,the level of ocean noise is estimated to be

m garbage (especially plastics (see Section A (1)(f) above on garbage and Section C (3) onmarine debris/litter and derelict fishing gear);

m fouling on anchors and chains; and

m ballast water.

Bilge water, commonly confused with ballastwater, is not a significant IAS threat because it isusually too contaminated. Ballast water is of thegreatest environmental concern because of thehuge quantity of water transported and the widevariety of organisms (protists, phyto- and zoo-plankton, invertebrates and fish) it carries (see alsoSection A (1) (b) above on bilge water and ballastwater).

These non-indigenous plants and animals canadversely affect the habitats they invade innumerous, often interactive ways. Adverse effectsof IAS, depending on the species, include:

m rapid reproduction (can spawn multiple timesper season) to form very large populations thatdominate the local community, altering foodwebs, habitat and ecosystem function;

m competition for food and habitat with, andpreying on, native fish and invertebratespecies, including their eggs and young,causing local extinctions during populationoutbreaks;

m formation of harmful algal blooms (HABs);

m cause of massive kills of marine life throughoxygen depletion, release of toxins and/ormucus;

m contamination of filter-feeders, such asshellfish; and

m cause of severe fouling problems oninfrastructure and vessels.

The adverse effects on biodiversity can bewidespread and affect entire ecosystems. Theestablishment of IAS tends to homogenizespecies composition and lower the number ofspecies, such that a few common species endup dominating a given community, with the loss ofunique and distinctive species and traits thatmade up the original and particular biodiversity atthat location. A well-known and sobering exampleof such a change in species dominance and thenin the whole ecosystem is the shift in Black Sea

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doubling every decade. In the northernhemisphere, overall ship noise at low frequencies(below 1,000 Hz) has increased by about 3decibels (dB) per decade over the past 60 years.It now seems to be growing at 3-5 dBs/decade.The larger the ship, the noisier it will be, and shipsize (tripling) and numbers (doubling within thenext 20-30 years) are steadily increasing,principally in the commercial ship sector (cargovessels, super tankers and cruise liners).

Sound travels about five times faster and overlarger distances in the sea than in the atmosphere,especially at low frequencies and when channeledby temperature and pressure gradients. Theeffects of underwater noise can extend muchfurther than similar noise levels produced on land.Particularly disruptive are the low-frequencysounds emitted during seismic surveys and sonaractivity, as well as from distant shipping andconstruction, which radiate over very large areasover long periods of time, resulting in chronicexposure by marine organisms to noise pollution.

The most powerful noises (explosives, air guns,sonar) can injure (including causing temporary orpermanent hearing loss) or kill organisms that areclose enough to the source of the noise. Noisefrom other activities is not usually as loud, but it ismore constant, and the resultant continuous andincreasing background noise pollution of theocean adversely affects marine organisms just ascontinuous and increasing background airbornenoise pollution adversely affects terrestrialorganisms, including humans. Continuous noiseis a source of stress which has been shown tocause chemical changes that adversely affectgrowth, reproduction and resistance to disease inhuman and other terrestrial animals. It is unlikely toleave marine animals unaffected.

Marine animals, such as cetaceans, often haveweak eyesight. Their world transmits light poorlyand is largely defined by acoustic information, as itis for many deep-sea fish, which live in a world ofdarkness. They must rely on sound tocommunicate, coordinate their movements,navigate, investigate and use their environment,find prey and avoid hazards such as obstaclesand predators. Under natural conditions, largecetaceans (including endangered species of

balaenopteridae (e.g., fin whale)), communicateand orient acoustically over thousands ofkilometres in the ocean. They are able to detecttopographic features more than 500 km away.

Increasing levels of anthropogenic noise in theoceans act like smog for acoustically sensitivespecies, obscuring signals potentially critical tomigration, feeding and reproduction. The maskingeffect of the increased ambient anthropogenicnoise has already impaired long-rangecommunication for mysticetes (baleen whales).Shipping noise, derived largely from propulsion,operates in the 20-200 Hz band, the dominantfrequency used by baleen whales forcommunication. The communication difficultiescaused for mysticetes by anthropogenic noise areexacerbated by their severe numerical depletiondue to whaling. To reach their few remainingcounterparts, they are obliged to communicateover much longer distances than theircommunication apparatus originally evolved toaccommodate. Moreover, any hearing loss theymight be suffering will further jeopardize their abilityto function acoustically.

Other observed adverse effects of noise pollutioninclude stranding and displacement from theirnormal habitat, tissue damage and mortality.Collisions with vessels (see also Section A (3)above) may be another consequence of noisepollution. Noise pollution may also adversely affectmating, feeding (e.g., ability to locate and captureprey), mother-young bonding, ability to detect andavoid predators and ships, growth and successfulreproduction, and, ultimately, longevity. For marinemammals, at least, hearing is their primary senseunderwater, as sight is ours on land. Their hearingplays a huge variety of crucial roles throughouttheir lifetime and an acoustically unpollutedenvironment is essential to their well-being andsurvival.

Although the effects of noise on marine mammalshave been the focus of most research so far,other marine organisms are increasingly beingshown to be not dissimilarly adversely affected bythis form of pollution; they include sea turtles, fish,seabirds and some invertebrates, e.g., shrimp,lobster, giant squid (Architeuthis dux) and crabs.Over 50 families of fish use sound to

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by stationary vessels can adversely affect thebenthos underneath. The effects would dependon the size and number of the stationary vesselsand the duration of their stay. As far as this authoris aware, there are no studies of these effectscaused by stationary vessels at sea. Extrapolationfrom near-shore studies comparing under-bridgewith bridge-free reference sites suggests thatreduction in local photosynthesis, and therefore inthe phyto- and zoo-plankton communities andthus in the food available to the benthiccommunity under the shaded area, with theattendant community and ecological changes,might reasonably be expected.

The obverse of abnormal shading during the dayis excessive light at night. Long-term stationaryships at sea that are lit up at night, especiallyduring lunar dark periods, can disrupt the light-dark cycles that condition many physiologicalmechanisms and ecological responses.Ecologically inappropriate lighting may haveadverse effects on the pelagic communities thatmigrate towards the surface at night and return todepth during the day, on predator-preyinteractions, and on the benthic community, all ofwhich are found in association with seamounts.

8. Washes and wakes

In general, washes and wakes must beconsidered in waters where the wake and washgenerated are greater than the naturalbackground wave conditions. The effect ofwashes and wakes on marine ecosystems andbiodiversity will vary with the type of habitat andecosystem involved and on how the wash andwake regime differs from the natural wave climateat a given habitat or ecosystem. This regime willalso depend on the number, size, speed andtype of vessels, including propeller and hullshape, and the transit frequency. Boat designcan reduce boat wake, particularly bow designand the hull profile under water. Different types ofvessel create different magnitudes of wash withdifferent wave energy levels. Damage caused bya wake is directly related to its height: forexample, a wave that is 25 cm high causes fivetimes more damage than one of only 12.5 cm.Ship wakes may cause unusually high near-bottom velocities at depths of 5-30 m. At such

communicate and obtain information from andabout their environment, as well as for defence,protection of territory and reproduction. Unique tofish is the lateral line, a band of sensory cellsrunning the length of their body on both sides thatcan pick up and amplify low-frequency sound.Fish suffer noise-induced hearing loss anddamage to eggs and larvae, they abandon noisyareas, and those with swim bladders passivelyreceive unwanted noise that is amplified throughthese organs.

Noise pollution also makes species communicatemore loudly, thereby further increasing overallambient noise levels in the ocean. Whale songsare longer when submarine detectors are on. Ifcetaceans don't ‘speak’ loudly enough, their voicecan be masked by anthropogenic sounds. Theseunheard voices might be warnings, finding of preyor preparations for net-bubbling. When onespecies begins to speak more loudly, it will maskthe voices of other species, eventually raising thevolume of noise across the whole ecosystem.

Noise has adverse cumulative and synergisticeffects on marine biodiversity and ecosystems,including seamounts and other habitats far fromcoasts and shipping lanes. Ocean acidification,one of the consequences of global warming dueto excessive CO2 emissions, can exacerbatenoise pollution: it makes noise louder, especiallyfor frequencies below about 10 kHz, as does thewarming of the ocean itself, also in the lowerfrequency range. See also Section C (1) onanthropogenic climate change.

The effects of noise were eloquently summarizedby Dr Sylvia Earle (2005): "Undersea noisepollution is like the death of a thousand cuts. Eachsound in itself may not be a matter of criticalconcern, but taken all together, the noise fromshipping, seismic surveys, and military activity iscreating a totally different environment thanexisted even 50 years ago. That high level ofnoise is bound to have a hard, sweeping impacton life in the sea."

7. Shading and lighting

Shading occurs when vessels spend a long timein one position at sea. Prolonged light reduction

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velocities, the impact of a typical ship wake onbottom sediments and aquatic wildlife at thesedepths is comparable with or can even exceedthe impact of wind waves whipped up by violentstorms, and considerably exceeds the effect oflocal currents.

Where the local ecosystem is adjusted to lownear-bottom velocities, fast ship-induced wavescan become a new environmental threat at certaindepths. An abrupt intensification of sedimenttransport processes at those depths may changethe existing balance of sediment distribution.Mobilization of larger sediments can result in rapidchanges to biological communities. Sedentaryorganisms may be relocated, crushed anddamaged as the rocks and boulders on whichthey are attached are rolled around.Resuspension of finer sediments can create anabrasive environment that may damage soft-bodied animals and algae and prevent sporesfrom settling. When sediments do settle out, theycan potentially smother benthic organisms andcover fish eggs and spawning grounds. Aquaticplants can be physiologically impaired if theirsurfaces are covered with silt. Resuspension ofsediments also increases the turbidity of the waterand, by blocking the light that reaches thebottom, can adversely affect benthic organisms.Another potential mechanical effect of ship waves,if the bottom is shallow enough, is enhancementof vertical mixing along the ship's path. Due to thetransport of nutrients from sediments and thelower water column into the euphotic layer,phytoplankton production may intensify but alsopromote eutrophication and HABs.

Environmental studies of washes and wakeshave, to the best of the author's knowledge, sofar only been conducted in shallow, confinedwaters. In open waters, the effect of washes andwakes compared to the natural wave processesis generally much less and is not usually a matterof concern. For seamounts in the open oceanwith no nearby shores, extrapolation from thenear-shore studies suggests that anyenvironmental effects are likely to be primarily afunction of the depth of the seamount summit,especially if that summit is shallower than about40 m.

B. Activities for which the ship servesprimarily as a platform

1. Archaeology

Archaeological activities relevant to this paper areusually conducted on shipwrecks. Insofar asthese shipwrecks are found on or nearseamounts, the environmental threats are thoselisted in Section A above from all ships. Thenature of their effects will be similar, and theiractual occurrence and extent will depend on thesensitivity of the archaeological team to theenvironmental threats posed by the presence oftheir ship over the site and the efforts made toreduce and preferably eliminate them.

As for the activity itself, defined by Dr KeithMuckelroy as "the scientific study of the materialremains of man and his activities upon the sea"(quoted in Verlaan, 1989), marine archaeology,when conducted to the highest professionalstandards, is not likely to pose substantial threatsto the marine environment, biodiversity andecosystems of the seamount. This is because thearchaeological value rests with the wreck in situ,unaltered by anthropogenic intervention since thevessel sank to the seafloor. Removal of anyremains, even if only for further study, "withoutpainstaking recording...of their archaeologicalcontext in situ, destroys the scientific value of theremoved object and diminishes the value for thesite as a whole for archaeologists, historians,oceanographers, and other scientists" (Ibid.).Hence archaeological investigations of deep-seawrecks focus on non-invasive and non-extractiveexamination. Technology makes it possible to doso. Nevertheless, the noise, light and otherdisruption associated with the presence ofresearchers, either indirectly via various remotelyoperated vehicles (ROVs), or directly in varioussubmersible human-occupied systems, cannotbe neglected as a source of potentially adverseenvironmental effects. See also Section B (11), onsalvage, which includes a discussion of ‘treasure-hunting’ at sea, which must not be confused witharchaeology.

The 2001 International Convention on theProtection of the Underwater Cultural Heritage(UCH Convention) strengthens in international lawthe preference for itu preservation (Art. 2(5)), and

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3. Bioprospecting

There is as yet no definition of bioprospecting ininternational law. The CBD Secretariat has definedbioprospecting as ‘‘the process of gatheringinformation from the biosphere on the molecularcomposition of genetic resources for thedevelopment of new commercial products’’(quoted in Warner, 2008), which suffices forpresent purposes. Information from the marinepart of the biosphere is the focus here, and ofparticular interest are the genetic resources ofmarine macro- and micro-organisms, the latterincluding archaea, bacteria, fungi and viruses.

Seamount ecosystems, with their often high levelsof endemism and biodiversity, and, depending ontheir depth and location, their situation in areas ofcomparatively extreme ambient conditions (e.g.,high pressure, low temperatures), are likely to beattractive sites for bioprospecting. As such, theyare vulnerable to the threats and their effects onmarine biodiversity and ecosystems associatedwith shipping activities (see Section A above).They are also vulnerable to excessive sampling bydifferent groups interested in the sameorganism(s), which can result in alteration or lossof habitat, and, depending on the organism,endanger its own survival as a population or evenan entire species, or that of groups and speciesdependent on it. Repeated visits to the sameseamount site directly and proximately exposesthese ecosystems to abnormal light, noise,extraneous biological matter and otherdisturbances. See also Section B (6) on marinescientific research, from which bioprospectingcannot easily be distinguished. The two activitiesare often conducted simultaneously.

4. Dumping

Dumping is distinguished from 'discharge' asdefined under MARPOL, which specificallyexcludes dumping. 'Operational discharges' areexcluded from the definition of dumping (seeSection A (1). Dumping under LOSC Art.1(5) andthe 1972 London Convention Art. III is defined as"any deliberate disposal at sea of wastes or othermatter from vessels, aircraft, platforms or otherman-made structures" and of "vessels, aircraft,platforms or other man-made structuresthemselves". The 1996 London Protocol adds to

sets out, in its Annex 36, rules for the responsiblemanagement of marine archaeology, including themarine environment. Article 3 specifically invokesthe UCH Convention's consistency with andemphasizes the primacy of the LOSC, whichreinforces the applicability of the marineenvironmental provisions of the LOSC to marinearchaeological activities.

In ABNJ, LOSC Article 149 provides that objectsof an archaeological and historical nature found inthe Area "shall be preserved or disposed of forthe benefit of mankind as a whole", which is notinconsistent with the foregoing analysis. As allactivities under the LOSC must be conductedaccording to the rules governing the protectionand preservation of the marine environment,seamounts in the high seas with archaeologicalattractions must also be protected from theenvironmental threats and effects caused bythese investigations.

2. Artificial islands and fixed/floatinginstallations

Construction and operation of such facilities everfurther out in the open ocean for such purposesas marine mining (see also Section B (5)), ocean-based energy generation from, e.g., currents,nuclear, ocean thermal energy conversion (OTEC),solar, waves), mariculture, and recreation (seealso Section B (10)) are likely to become morecommon as suitable coastal space becomesincreasingly rare.

Any construction and operation of such facilities inthe vicinity of, or directly over, seamounts willinvolve threats to marine biodiversity andecosystems. The degree of threat and actualimpacts will vary according to facility siting anddesign, construction methods and materials, andoperational requirements, but include effectsassociated with shipping (see Section A above),as well as those arising from construction andoperation, including many of those addressed inthe present Section B (e.g., (4) dumping; (9)piracy/criminal activities; (10) recreation; (12)undersea cable- and pipeline-laying). Moreover,such facilities may interfere with migratory andspecies dispersal routes, species distribution, andcurrent flow patterns.

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the definition of dumping, "any storage of wastesor other matter in the seabed and the subsoilthereof from vessels, aircraft, platforms or otherman-made structures at sea; and anyabandonment or toppling at site of platforms orother man-made structures at sea, for the solepurpose of deliberate disposal" (Art. 1(4)(.1)(.3-.4).

‘Wastes or other matter' that may still be dumpedunder the London Protocol, albeit with permit,currently includes: dredged material; sewagesludge; fish waste, or material resulting fromindustrial fish processing operations; inert,inorganic geological material; organic material ofnatural origin; bulky items primarily comprisingiron, steel, concrete and similar harmlessmaterials, for which the concern is physicalimpact, and limited to those circumstances wheresuch wastes are generated at locations, such assmall islands with isolated communities, having nopracticable access to disposal options other thandumping; and (since 2008) storage of CO2 underthe seabed in sub-seabed geological formations(SSGFs). However, the disposal or storage ofwastes or other matter directly arising from, orrelated to the exploration, exploitation andassociated offshore processing of seabed mineralresources is not covered under the dumpingtreaties (see Section B (5) for threats and effectsin association with marine mining).

Insofar as any of these materials, even withpermit, are dumped in or near seamounts, theadverse effects will include alteration, degradationand destruction of habitat, both on the seafloorand in the overlying water column, anddestruction of and injury to marine organisms,especially sessile and slow-moving ones, by, e.g.,smothering, increased local sedimentation andturbidity, oxygen depletion, and pollution fromdumped waste that is contaminated bysubstances such as those described in Section A(1) above.

Although the dumping of radioactive wastes wasbanned in 1993, these have been dumped asrecently as 1993, and perhaps thereafter as well –especially in the North Atlantic, the Arctic Ocean,the north Pacific, and the Sea of Japan/East Sea.Also dumped in the oceans were nuclearsubmarines, their reactors and warheads,

contaminated cooling water from reactors,conventional and chemical munitions, nerve andmustard gas, live bombs and other explosives,and whole ships, often still carrying munitions.Military dumping sites are not known to bemonitored for their release of radioactivity, or forother noxious materials, such as nerve gases.These sources of radioactive, chemical and heavymetal pollution can still constitute a threat toseamounts in the open ocean, due to transportby currents. See also Section B (7) on militaryactivities and Section C (5) on radionucleides.

5. Marine mining

a. Minerals – fueli. Oil and gasSeamounts themselves and their immediatesurroundings are unlikely to be of interest for oiland gas prospecting and exploitation because ofthe very different geological conditions governingthe formation of seamounts on the one hand andoil and gas deposits on the other. However, as oiland gas activities move ever further offshore andever deeper into the sea, some seamounts maybe located near enough to or directly under theshipping route to and from areas with suchpotential that these activities could adverselyaffect seamount ecosystems. The shippingthreats and their effects (Section A, above) will berelevant here, as will many of the threats and

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Oil pipeline. © Subsea World News

Furthermore, the released gas will eventually enterthe atmosphere, where, as it is 20 times morepotent a GHG than CO2, it will exacerbate globalwarming, with the attendant deleterious effectsthereof on the marine environment and thus alsoon seamount ecosystems (see also Section C (1)on anthropogenic climate change). A slopecollapse may also generate a tsunami, but theeffects of the latter are unlikely to be felt onseamounts unless they are very shallow and closeto a coast. Even during controlled drilling, theenvironmental effects of any accidental excessiverelease of gas to the water column and theatmosphere must be considered. Finally, methanehydrates do not occur in discrete formations –they are dispersed throughout the sediments,such that mining them will require large-scaleremoval of sediments, entailing concomitantdestruction and disruption of their fauna andassociated ecosystems, with all the environmentalconsequences thereof in addition to thosederiving from the creation of additional turbidityand sediment suspension. Their presence mayalso present a risk, especially of explosive gasrelease, to oil and gas operations, with all theattendant environmental consequences.

b. Minerals – non-fuel

i. Ferro-manganese nodules and crustsThese deposits are rich in economically importantmetals, including, in particular, Mn, Ni, Cu and Coin both, and Pt in crusts. The deposits of resourceinterest are not associated with hydrothermal ventprocesses or ecosystems. Depth-wise, the mosteconomically attractive crusts and nodules arefound, respectively, on hard, sediment-freesurfaces of seamounts at about 1,000-2,500 mand in sediments at about 4,000-5,500 m. Bothdeposits are sources of hard surfaces in the deepsea, with their own communities of organismsdependent on hard surfaces – i.e., they cannotlive on sediments. Mining entails removal of thesehard surfaces in the case of both deposits, and,in the case of nodules, massive disruption of theassociated sediments as well.

Consequently, in addition to the destruction of thecommunities themselves, crust and nodule miningalso destroys their habitat. Nodules and crusts ofinterest here form extremely slowly, at most, for

effects in the present Section B (e.g., (4)dumping; (9) piracy/criminal activities; (10)recreation; (12) undersea cable- and pipeline-laying).

Prospecting and exploitation involve suchenvironmental threats and their effects as: noise(from air guns, sonar, machinery, drilling); pollutionfrom drilling muds and drill cutting piles, which canbe contaminated by hydrocarbons andchemicals, including drilling fluids; leaks and spillsof oil and gas; and destruction of benthic habitatand sessile organisms. If installations (e.g., rigs,platforms) are constructed or brought in andplaced, the effects associated with those activitiesmust be considered (see also Section B (2) aboveon the construction of offshore installations andartificial islands).

ii. Methane hydratesThis potential fuel source is composed of amolecule of methane held in a lattice of ice, i.e.,frozen molecules of water. In the ocean it is foundat up to 2,000 m depth under polar seas and oncontinental slopes. As with oil and gas deposits,methane hydrates are unlikely to be found on ornear seamounts, but, as also with oil and gasdeposits, seamounts may be located in the pathof their eventual exploitation, with similar potentiallyadverse environmental consequences.

However, should methane extraction take placeon a commercial scale, the following threatsspecific to this activity that are relevant toseamount biodiversity and ecosystems must beconsidered. These hydrates are important to themaintenance of slope stability. Their removal couldtrigger massive underwater slides of sedimentsdown into the deep sea, generating extreme andprolonged turbidity, smothering the benthos anddestroying habitats, communities andecosystems, as well as releasing the gas into thesea where its effects are not well studied; asmethane is generally associated with anaerobic orhypoxic processes, it is unlikely to be benign inwaters that are normally oxic. An example isprovided by the Storegga Slides off Norway, ofwhich the latest – so far – occurred around 6100BCE, when a 290-km stretch of coast slumpedinto the sea and some 3,500 km3 of materialcascaded into the deep sea.

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nodules, a few mm every million years, whilecrusts form even more slowly. These are noteasily renewable substrata – or resources. In thecase of the communities dependent on thenodules themselves, it is unlikely thatrecolonization can occur at all, given that therequisite hard surface represented by nodules hasbeen removed. In the case of crusts, the newsurface exposed after crust removal (and withcurrent technology, the top part of the underlyingsubstratum will be removed as well), even thoughit is hard, may not be suitable for recolonization bycrust-associated organisms. The only deep-seaseamount crust colonization experiment carriedout in situ known to (and conducted by) thisauthor (Verlaan, 1992) suggests that somespecies may require crust for recruitment.

Recolonization of the sediment-associatedcommunities may occur, but it is not known howlong it will take. It is known that deep-seacolonization processes are extremely slow.Furthermore, given the lack of knowledge on thedegree of endemism in the sediment communitiesassociated with nodule deposits, it is unknownwhether the same communities would – orcould – in fact regenerate in areas where noduleshave been removed. Finally, it is not only sessileand less mobile organisms that are potentiallyaffected by nodule and crust mining. The effectsof the removal of these deposits on associateddemersal and other mobile organisms areunknown: they may have been able to escapedestruction by the mining operation itself, but theirrequirements for these deposits in situ (e.g., toattach eggs, to provide refuge for juveniles) willnot be met.

The potential adverse environmental effects areunlikely to remain confined to the mine site. Inboth cases, but particularly with sediment-hostednodules, mining can generate massive sedimentplumes in the water column that can smother andsuffocate sessile and less mobile benthic anddemersal organisms at and downstream of themine site, as well as increasing the turbidity of thewater, which interferes with processes dependenton visibility, such as bioluminescence. It isunknown whether resuspension of metal-richsediments will also render the ambient watercolumn toxic because of the enhanced

concentration of potentially toxic metals in thewater, but this possibility should not beoverlooked. Sediment plumes ejected near thesurface could interfere with light penetration and,hence, photosynthesis, and disrupt the local foodweb. It is also possible that the nutrients broughtup from deeper water with the sediments andejected near the surface may cause productivityblooms which the local environment cannotassimilate, causing eutrophication, HABs, hypoxiaand ecosystem disruption. Finally, theenvironmental threats and their effects associatedwith shipping (see Section A above), and also tosome extent with oil and gas recovery (seeSection B (5) (a) (i) above) are applicable here.Because of their seamount location, crust miningpresents a particularly important threat toseamount ecosystems.

ii. Polymetallic sulphides These deposits form by hydrothermal processesand are found associated with hydrothermal ventsand their ecosystems in volcanically activesubmarine areas. They are rich in economicallyimportant metals, including, in particular, Au, Ag,Cu and Zn. Mining is likely to occur, at leastinitially, at inactive vent sites, which pose fewertechnological challenges in terms of dealing withthe extremely hot, corrosive fluids emitted fromactive vents. The profuse communities (tubeworms, clams, etc.) so characteristic of activevents vanish when the vents become inactive;hence these communities are unlikely to be at riskfrom mining activities unless the inactive ventmining sites are near enough to active sites toaffect the latter, e.g., by sedimentation orshipping-related threats.

The inactive vent sites have their owncommunities, about which little is known,including how dependent they are on the metal-rich substratum of the vents themselves and ofthe surrounding sediments. Mining will remove theformer and disrupt the latter, with environmentaleffects that are unknown but which canreasonably be surmised. Based on knowledge ofdeep-sea ecology in general, and offerromanganese nodule and crust work inparticular, the effects are likely to take a very longtime to dissipate where the sediment-associatedcommunities are concerned, and not at all for the

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refers to hydrographic surveys, as well as simplyto 'surveys' and to 'research', albeit much lessfrequently than it refers to MSR. These differencesare important – particularly in terms of theconditions governing the right to conduct theactivity, which vary according to whether it is (orcan be argued to be) MSR or not – but they willnot be addressed further here.

For the purposes of this paper, MSR is construedas encompassing all activities designed to obtaininformation about the ocean in the broadestpossible sense. These will include hydrography,mapping and surveying, regardless of whether theactivity has a military or industrial/commercialobjective. Bioprospecting (see also Section B (3)above) can fall into the MSR category as definedhere as well. It is the potential for environmentalthreats posed by this information-gathering toseamount biodiversity and ecology that isexamined here.

Information-gathering can be either passive, i.e.,as minimally intrusive as possible, or active. It isthe active form that is likely to have adverseenvironmental effects. It includes drilling,sampling (e.g., cores, dredges, trawls and nets,all of various sizes and designs), acousticemissions, such as sonars, at variousfrequencies, as well as seismic air guns,explosions, deployment of light, and in situexperiments. Industrial/commercial and militaryinformation-gathering activities are likely to bemore environmentally problematic because theyare usually much more intrusive in terms ofduration, intensity and scale than scientific ones.In particular the use of sound (sonar and seismic)by industry and the military for their information-gathering is a grave cause of concern (see alsoSection A (6) above on noise).

Information-gathering by scientists is usually donein a context that involves hypothesis-testing,whereby it is usually necessary to leave theenvironment about which and wherein thehypothesis is being tested as undisturbed aspossible for the observations made to beaccurate and the conclusions drawn to bemeaningful. This context generally entails scientificintrusions on scales that are unlikely to haveenvironmentally adverse effects. However, recent

communities actually living in or on or otherwisedependent on the mined polymetallic sulphidedeposit itself, as that will have been removed.

Habitat degradation and destruction, the latterirremediable in the case of the deposit itself, arelikely to be the result of polymetallic sulphidemining. Furthermore, it is unknown whether and towhat extent the organisms associated withinactive vent sites are endemic. Adverseenvironmental effects of mining on seamountecology and biodiversity, if any, will be a functionof the proximity of seamount communities to themine sites and the scale of the mining operation,and are likely to be similar to those discussedabove (Section 5 (a) (i) and (b) (i) above for Fe-Mndeposits and oil and gas). Again, sedimentplumes, if uncontrolled, are likely to be a majorthreat.

iii. Phosphorites, limestone, sand and gravel Depending on their location, depth and geologicalhistory, seamounts can be a source of supply forthese mineral resources. Each resource isassociated with a particular habitat and adistinctive community. Mining of the resource willdestroy the immediate habitat and its associatedcommunity of sessile and less mobile organisms,as well as making it unavailable to demersal andother mobile organisms. The surroundingunmined habitat and its communities will bedegraded by environmental effects similar tothose described above (see Section 5 (a) (i) oiland gas, (b) (i) for Fe-Mn deposits, and b (ii) forpolymetallic sulphides).

6. Marine scientific research

Marine scientific research (MSR) is as yetundefined in international law. The LOSC devotesall of Part XII to MSR, and addresses it elsewherein the body of the text as well. In practice, MSRcan overlap with surveys and mapping, which areessential for a variety of ocean activities, includingfuel and non-fuel mineral development andexploitation, cable and pipeline laying, installationof equipment and structures offshore, militaryoperations, exploration for resources, andconducting MSR itself. The LOSC also recognizesthe existence of a distinction between MSR andother forms of information-gathering at sea, as it

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years have seen the development of information-gathering by scientists that must – by the verynature of the underlying hypothesis to be tested –intentionally perturb or manipulate the marineenvironment on scales that not only will haveenvironmental effects but effects that cannot beguaranteed to be benign.

One such experiment involved periodicunderwater release, over several years, of low-frequency acoustic signals that could be receivedat distances of 18,000 km from their source, andthus across entire ocean basins, to investigatewhether global ocean temperatures wereincreasing. An increasing number of experiments(a dozen at the time of writing) are seeding up to(so far) 100 km2 in the equatorial and sub-ArcticPacific and the Southern Ocean with iron, anessential micronutrient, in order to determinewhether the low level of phytoplankton productivityobserved in these regions is related to a possibleinsufficient availability of iron (see also Section B(8) on ocean-based climate-change mitigation).Placement on the seafloor of a network of oceanobservatories linked by cables to the land isongoing in the Atlantic and the Pacific; theEuropean Seafloor Observatory Network(ESONET) is projecting some 5,000 km of cables(see also Section B (12) (a) on cables).

In conclusion, the extent to which this information-gathering is likely to cause adverse environmentaleffects on seamount biodiversity and ecosystemswill depend on the spatial and temporal scale ofthe activity, and its nature and intensity. Theenvironmental effects discussed elsewhere in thissection in relation to specific underwater activities,and the general shipping-related environmentalthreats and their effects set out in Section A, coverthe scope of the threats and effects that may beexpected from MSR/information-gathering.

7. Military activities

The environmental effects of military activities atsea are difficult to assess; national securityarguments tend to trump all other considerations,including environmental ones. The military is notnecessarily subject to the same national andinternational marine environmental rules applicableto marine activities conducted by other segments

of society. In many cases the military may beformally exempted from such rules by national andinternational law. It is not unlikely that militaryactivities at sea will pose the threats and causethe effects outlined in Section A above, as well asin Section B (2) on construction of artificial islandsand fixed/floating installations, Section B (4) ondumping and Section B (6) on MSR/information-gathering. In addition to munitions disposal (seeSection B (4) above under dumping), militaryexercises and weapons testing, which ofteninclude bombing and shelling of islands,deleterious effects also involve concentrated,albeit intermittent, sources of extreme noise (seeSection A (6) above) and more intense inputs ofthe environmental stresses already describedabove.

A potential threat to seamounts specifically is thepossible prolonged presence of submarines,which find seamounts to be convenient locationsto conceal themselves. Noise is probably not theprincipal threat here because submarines place apremium on silent operations and movement.Collisions with marine mammals, grounding andIAS (see Section A (3-5) above) are possiblethreats, as well as operational or accidentaldischarges of the substances listed in Section A(1), whose effects might be exacerbated by theproximity of the submarine to the seamountshould any of these threats materialize from thatsource.

8. Ocean-based climate-change mitigation

Ocean-based climate-change mitigation activitiesfall into one of two broad categories:

a) Lowering atmospheric CO2 by accelerating itsremoval from and delaying its return to theatmosphere;

b) Lessening incoming solar light and heat bydeflecting it directly or by increasing theplanet's albedo (reflectivity), thereby offsettingwarming caused by rising CO2 (and otherGHG emissions).

In category (a), atmospheric CO2 is captured andplaced in the oceans for long-term 'storage' awayfrom the atmosphere. This category includes:

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If these activities really are able to effectivelymitigate anthropogenic climate change, they mustbe conducted on long temporal scales (severaldecades) and on huge spatial scales (multiplelarge sites in all oceans). Should this indeedoccur, the threats to and effects on marinebiodiversity, marine ecosystems and marineenvironment as a whole are likely to be sufficientlyadverse that it would be futile to single outseamounts as subjects of particular environmentalconcern. A highly qualified exception to thisdismal scenario might perhaps be made, at leastinitially, for CCS in SSGFs. But this must beproperly carried out; i.e., no escape of CO2 fromthe SSGFs must occur, because if it does, oceanacidification, already a problem in the upper watercolumn (see also Section C (1)) will beexacerbated at depth.

Consequently, for the purposes of this paper, theprincipal immediate threat to seamountbiodiversity and ecosystems from ocean-basedclimate-change mitigation activities derives fromtheir testing in the vicinity of seamounts, whereproximity and/or the effect of local and regionalcirculation and productivity patterns operate toconcentrate their effects on these seamounts.The effects will include all the generic shipping-based effects set out above in Section A, and theeffects associated with artificial islands andfloating installations, dumping and MSR in SectionB (2), (4) and (6) respectively.

Effects specifically associated with oceanfertilization are not as yet fully characterized, butenough is already known about the processesinvolved to predict that these will include changesin species and community composition, as wellas in the productivity of the phyto- and zoo-plankton, in the benthic, demersal and pelagiccommunities, and the food web as a whole.Immobile benthic communities, which areultimately dependent on surface productivity, arelikely to be especially vulnerable to thesechanges. Furthermore, ocean acidification (seealso Section C (1) on anthropogenic climatechange) may be exacerbated by the increaseddissolution of CO2, and hypoxic or anoxic zonesmay develop as a result of increaseddecomposition of organic matter in the watercolumn where circulation is such that oxygen is

i) capture of CO2 from point sources ofemission, and its transfer (by ship or pipeline)to and storage (CCS) in SSGFs. TheseSSGFs include depleted offshore oil and gasfields and sub-seabed saline aquifers; theyexist worldwide and are said to be able tostore quantities of CO2 equivalent to somedecades of global emissions. At the time ofwriting, CCS in SSGFs has begun on amodest scale off Norway.

ii) capture of atmospheric CO2 by oceanfertilization. This involves increasingphytoplankton productivity through targetedspecific nutrient addition (e.g., iron, nitrate,phosphate, urea) or general nutrientenhancement (by artificially inducing upwellingof nutrient-rich deep ocean water) to surfaceseawater, thereby increasing the concomitanttransport of fixed carbon to depths fromwhich, it is hoped, this carbon would beunlikely to re-enter the atmosphere as CO2 fora century. See also above under Section B (6)on MSR)

In category (b), the effect of sunlight is reduced byincreasing the albedo and cover of marine cloudsthrough injection from ships of aerosols composedof seawater droplets and dissolved salts into theatmosphere at 300 m altitude. As the dropletsevaporate, their salt crystals reflect sunlight andbecome condensation nuclei for new droplets,thereby increasing marine cloud cover andreflecting even more sunlight. To the best of thisauthor's knowledge, this planetary shading optionhas not yet been tried at sea. Furthermore, oceanfertilization and planetary shading may be mutuallyincompatible, as the latter will reduce the lightneeded for photosynthesis in the former, withoutwhich less carbon will be fixed from CO2 and lesscarbon will therefore be available to sink to depth(see also Section A (7) above on shading).

Basic technical feasibility, if not actualeffectiveness, has been demonstrated for themethods proposed. Economic feasibility is notaddressed here, other than to offer the view that itis unlikely to be an issue, because financing willbe(come) available if the motivation (which neednot be environmental) to engage in one or more ofthese activities is great enough.

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either not or only inadequately replenished. Insummary, the effects of ocean fertilization onseamount communities are unlikely to be benign.

9. Piracy/criminal activities

Arts. 100-107 of the LOSC deal with piracy,underlining its importance as an issue of globalconcern. The definition of piracy in LOSC Art. 101is complex, but essentially it requires the use of aship or aircraft to commit any illegal act of violenceor detention, or any act of depredation directedagainst another ship or aircraft or against personsor property aboard same, in ABNJ. TheConvention for the Suppression of Unlawful ActsAgainst the Safety of Maritime Navigation, 1988(SUA Convention) and its two Protocols,promulgated under the auspices of IMO, elaborateon the piracy provisions of the LOSC, and, withparticular relevance to the purposes of this paper,requires that the measures taken by a Stateagainst these offences are environmentally sound.

With regard to threats posed to seamountecology and biodiversity by piracy and othercriminal activities at sea, the threats and effectsdiscussed in Section A above are implicated to agreater or lesser extent, depending in particular onthe fate of the pirate vessel and the victim vessel,especially if these vessels are damaged orwrecked near a seamount. Since pirates areranging further and further out to sea, up tohundreds of kilometres from shore, the remotelocation of seamounts is not likely to besubstantially shielded from their attentions,especially if the seamount itself or waters nearbyattract ships for legitimate activities such as thoseenumerated elsewhere in this section.

10. Recreation

Ocean-based recreation is a major global growthsector in which the remoteness, inaccessibilityand ecological fragility and uniqueness of sites area particularly potent inducement to visit.Seamounts, with their enhanced biodiversity, arelikely to be attractive marine recreational sites,offering a variety of opportunities, depending ondepth, for surface and sub-surface marine tourismby cruise ships and submersibles, respectively, aswell as for swimming, snorkeling and diving,

yachting (motor and sail) and sports fishing (thisfinal item is addressed in Chapter 2).

All the threats and their effects covered in SectionA are likely to be involved to a greater or lesserextent if seamounts become a recreational site,as are, in particular, the threats and effects underSection B (2) construction of artificial islands andfixed/floating installations, (4) dumping and (9)piracy. Tourist submersibles can introduce lightpollution at depth, as can cruise ships at night inthe upper water column if they remain on station.Both are a source of proximate noise, as are thesupport vessels for swimming, snorkeling, divingand sports fishing. Other adverse effects includeremoval of shells, corals and other marineorganisms as souvenirs, as well as the potentialfor disturbance of seamount sites important forscientific research, monitoring, biodiversityconservation, and their historical andarchaeological value.

11. Salvage

Salvage is defined in the 1989 InternationalConvention on Salvage as "any act or activityundertaken to assist a vessel or any otherproperty in danger in navigable waters or in anyother waters whatsoever” (Art.1(a)). The conceptof salvage is designed to promote the voluntaryrescue of goods and vessels imperiled at sea.The Salvage Convention provides for anenhanced salvage award that takes into accountthe skill and efforts of the salvors in preventing orminimizing damage to the environment. It alsoprovides for ‘special compensation’ to be paid tosalvors who have failed to earn a reward in thenormal way (i.e., by salving the ship and cargo)but who have prevented or minimized damage tothe environment. Damage to the environment isdefined as "substantial physical damage to humanhealth or to marine life or resources in coastal orinland waters or areas adjacent thereto, causedby pollution, contamination, fire, explosion orsimilar major incidents"(Art.1(d)). However, if thesalvor fails to prevent or minimize environmentaldamage, special compensation may be denied orreduced. Therefore, although the salvage processcan entail risks to the environment, the salvagereward system provides a strong incentive tominimize environmental damage.

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Newfoundland via the seafloor of the NorthAtlantic. Some 100,000 km of submarine cableare now being laid every year. Most internationaltelephone and internet communications travel viasubmarine cables. Although most cables are stillbeing laid in the North Atlantic, they are nowfound in all the oceans, and cable-laying isincreasing in particular in the Indian and PacificOceans. As cables are best placed on smooth flatseafloor, the likelihood of their placement directlyon topographically complex seamounts, and thusof their ability to directly affect seamountbiodiversity and ecosystems, is low.

Insofar as cables are placed on the seafloor nearseamounts, the process of their placement,maintenance and repair may adversely affectadjacent seamount ecosystems, depending ontheir proximity to the cable-related activities.Because bottom-trawling is the main threat tosubmarine cables, they are generally buried 1-3 mbelow the seabed where the seabed is at depthsstill accessible to bottom trawls (1,500-2,000 mwater depth). Burial involves digging a narrowtrench (cables, when armoured, are about 50 mmin diameter), inserting the cable and covering itup. In addition to the effects of the presence ofthe ship as outlined in Section A above, and thephysical destruction of the seafloor itself and anyorganisms that were unable to escape thetrenching, the other principal environmental effectof this process is the creation of sedimentplumes. These can spread far from the site, ifcurrents and seafloor conditions are conducivethereto, with the associated well-knownsmothering and turbidity effects describedelsewhere in this paper (e.g., Section B (5) onmarine mining).

In deep water where bottom-trawling is not a riskand the seabed is not rough, cables are notarmoured (and are thinner, ~17-21 mm indiameter) and are placed directly on the seabed.Under these circumstances the environmentaleffects are likely to be minimal.

The increasing use of seabed oceanobservatories in MSR projects, which by their verypurpose may require their placement inenvironmentally sensitive areas, such asseamounts, necessitates cabling to connect the

For ships or goods imperiled near or overseamounts, salvage operations are most likely tobe conducted by specialized salvage tugs orvessels, which may also include diving facilities.Rapid action is especially necessary offshore inexposed waters because sea state and weatherconditions can deteriorate quickly, such thatsalving is not possible until conditions improve, bywhich time the vessel, its cargo, and theenvironment may all be beyond help. Under suchcircumstances, saving the vessel's cargo andequipment is often a higher priority than saving thevessel herself. The cargo may pose anenvironmental hazard or include expensive itemsand materials; the equipment may includevaluable machinery. In this case, salvors will focuson rapidly removing the goods of interest, andalthough they may deliberately destroy the hull todo so most efficiently, it is in their financial interestto do so in an environmentally responsiblemanner. Although it will never be environmentallybeneficial to seamount ecosystems andbiodiversity to have a vessel come to grief nearbyor on it, modern salvage operations are not likelyto exacerbate the environmental consequencesunduly, and they may even mitigate or prevent them.

This sanguine assessment is unlikely to beapplicable to marine treasure-hunting. Oftenconfused with both marine archaeology (see alsoSection B (1) above) and salvage – a confusionwhich is not necessarily scrupulously cleared upby treasure-hunters – marine treasure-hunting isdriven by profit motives to retrieve items withmarket value from wrecks at minimum cost to thetreasure-hunters. Environmental concerns are notusually uppermost in their calculations. Seamountecosystems bearing wrecks of interest totreasure-hunters are therefore likely to be more atrisk from their attentions than from those of salvorsor marine archaeologists. For both salvage andtreasure-hunting, however, the threats and effectsdescribed above in Section A remain applicable;see in particular Section A (4) on grounding andshipwreck.

12. Undersea cable- and pipeline-laying

a. Cables

Submarine cable-laying began in 1858, when thefirst undersea cable linked Britain and

THREATS AND EFFECTS


observatories to their land-based stations, andshould be considered an emerging potential threat.

b. PipelinesPipelines are so far only used for transporting oiland gas, although CO2 could join them in thefuture (see also Section B (8) above on ocean-based climate-change mitigation activities).Pipelines are much bigger (up to 900 mm indiameter) and require more construction work fortheir placement than cables, as well as moreenvironmentally intrusive maintenance and repair.They are not often buried, but more usually placeddirectly on the seafloor, where again, as withcables, smooth topography is preferred. Pipelinescan also leak or break, releasing their contents tothe marine environment, with effects that willdepend on the quantity, type of substance, andlocal temperature and pressure, as well as thenature and proximity of marine organisms,communities and ecosystems. As with cables,pipelines are unlikely to be placed directly onseamounts, but they may prove to be a threat toseamount ecosystems if they are placed on theseafloor nearby.

C. Threats from activities not involvingships

This final section briefly highlights some of themost important overarching anthropogenic threatsto which seamount biodiversity and ecosystemsare all vulnerable. They constitute a set of chronic,growing stresses that must be considered inassessing the possible effects of the specificadditional threats to seamount ecosystems andbiodiversity described in Sections A and B.

1. Anthropogenic climate change

The oceans and the atmosphere are closelylinked; between them they account for the bulk ofheat and gas circulation on the planet.Anthropogenic climate change is caused by theexcessive accumulation of GHG in and hence theexcessive warming of the atmosphere by activitiessuch as fossil fuel burning, deforestation(especially trees and mangroves) and cattleproduction. This warming will alter the pattern ofheat and gas distribution on the planet. Changesin precipitation (rain and snow), ocean circulation(e.g., currents, up- and down-welling),

temperature, salinity, storm patterns and paths,and sea level can be expected. Adverse effectson marine ecosystems and biodiversity includeocean acidification, ocean warming, oceanoxygen content reduction, eutrophication, HABs,turbidity, noise amplification and methane leakage.These all contribute to marine habitat degradation.Migration routes, nutrient supplies, food webstructures, species and community compositioncould change such that entire groups oforganisms and ecosystems might disappear. Thejoint, several and cumulative effects of warm,acidic, hypoxic, cloudy, noisy, methane-richwaters on marine ecosystems, benthic andpelagic communities, and the physiology,behaviour and reproduction of biotaunaccustomed to such stressful conditions arelikely, at best, to reduce their resilience to and thepotential for them to recover from or adjust to theeffects of the threats derived from activities suchas those outlined in Sections A and B above.

From this sad litany of adverse effects ofanthropogenic climate change, ocean warmingand ocean acidification may be singled out aslikely to have the most immediately evident effectson seamount ecosystems and biodiversity. Manymarine organisms live at temperatures near theirphysiological maximum tolerance, or theirdistribution and functioning are conditioned bytemperature; even an apparently minor increase inthe ambient temperature of their waters ('thermalshock') can have disproportionately large negativeeffects on them. Thermal shock may also provideopportunities for thermophilic IAS to colonizeareas whose keystone native species (e.g.,gorgonian corals for seamounts) are weakened byincreased temperatures.

Carbonic acid forms when CO2 dissolves inseawater, which lowers the pH. Under normalcircumstances, this acid is buffered withcarbonate and bicarbonate. However, the excessanthropogenic production of CO2 is causing it toenter the ocean at a rate which is greater than theability of the ocean to neutralize it. The oceans arenaturally alkaline, with a pH of approximately 8.2,which can vary by up to 0.3 points depending onseason and location. At present the pH of theoceans is down by 0.1 points, and is predicted todrop – and thus increase acidity – by at least a

THREATS AND EFFECTS



THREATS AND EFFECTS

further 0.4 units, which exceeds the greatestnatural variation in pH observed so far. As withtemperature, most marine organisms can toleratepH changes within only a narrow band.

Ocean acidification will adversely affect the widevariety of organisms (including phytoplankton,crustaceans, molluscs, corals, sponges andechinoderms) that need calcium carbonate fortheir skeletons, shells and other structuresessential to their survival. Not only will theincreasing acidity of ocean waters make it moredifficult for these organisms to build them, thesestructures are also likely to disintegrate, ascalcium carbonate dissolves under acidicconditions. Entire ecosystems that depend on acalcium carbonate substratum can be placed atrisk. Living in increasingly acid waters is nothealthy for non-calcifying organisms either; in fish,squid and shrimp, for example, respiratoryprocesses can be impaired.

Finally, and ironically, recent research indicatesthat lower pH may hamper the ability ofphytoplankton to photosynthesize, by reducingthe bioavailability of Fe, an essential nutrientpresent in limited amounts in large parts of theopen ocean (see also Section B (8) above, onocean-based climate-change mitigation). Initialresearch indicates that increasing acidity (lowerpH) is likely to affect the speciation, and hencethe bioavailability, as well as the potential toxicity,of other essential trace metals (see also Section A(1) (g) above on heavy metals). As pointed out inSection A (6) above, low pH also amplifies noisein the sea.

2. Land-based activities

Land-based activities (including GHG emissions)constitute by far the most important (at least 80%)sources of marine pollution. Land-based sources(LBS) of pollution are the principal threat to themarine environment as a whole. Once in the seamost pollutants, through currents and gravity,eventually find their way to the deep-seafloor, withthe potential to damage seamount ecosystemsand biodiversity en route and on arrival. Despitethe attention given to shipping in this paper,because of its seamount focus, shipping onlyrepresents ~10% of all sources of marine

pollution. There is certainly room for improvementwith shipping, but the elephant in that particularroom is LBS, for which no land-based, global,legally binding treaty exists. The only legallybinding global treaty addressing LBS is the LOSC.

Marine debris or litter, of which again the bulk(80%) is derived from LBS, represents the majorthreat from LBS to seamounts; its effects arediscussed in the following section.

3. Marine debris or litter

Marine debris, also known as marine litter, isanthropogenic waste that has deliberately oraccidentally entered the ocean. Oceanic debris isthe focus of this section, as it is most relevant toseamount ecosystems. About 20% of marinedebris is derived from marine activities; the restcomes from LBS. Plastics and other syntheticmaterials are the most common components –some 60-80% – of marine debris, and they alsocause the most problems for marine organisms,especially marine mammals, seabirds and seaturtles. As pointed out in Section A (1) (f) above ongarbage, the disposal of plastic at sea from shipsis prohibited under MARPOL Annex V. The needfor such a prohibition – and for its extension toLBS of plastic, for which it is the principal source,is evident when its adverse effects on the marineenvironment, biodiversity and ecosystems areconsidered.

Plastic degrades very slowly and can float foryears. It accumulates in open-oceanoceanographic features such as convergencezones, gyres and eddies, as well as fishinggrounds, which are also biologically diverse areas;it also concentrates along shipping lanes. Themass of plastic in the oceans may be as high asone hundred million metric tons. The Great PacificGarbage Patch in the north Pacific gyre has a veryhigh level of plastic particulates suspended in theupper water column. In samples taken in 1999,the mass of plastic exceeded that of zooplanktonby a factor of six. It has been estimated that over13,000 pieces of plastic litter are floating on everysquare kilometre of ocean surface.

Plastic provides vectors for the spread of IAS thatare then transported to new areas via ballast


environmental effects grows. There is increasingevidence that such particles are ingested bymarine organisms, with the potential for: physicaldisruption and abrasion; toxicity of chemicals inthe plastic; and toxicity of adsorbed POPs. TheIMO/FAO/UNESCO-IOC/ WMO/WHO/IAEA/UN/UNEP Joint Group of Experts on the ScientificAspects of Marine Environmental Protection(GESAMP) at their 36th meeting agreed to furtherexplore the scope of this issue through an expertworkshop, focused on the occurrence andpotential impact of micro-plastics, both due totheir intrinsic properties (size, shape, composition)but especially as a vector for contaminants.

Fish, marine mammals, sea turtles and seabirdscan mistake plastics for food. Plastic bags inparticular resemble jellyfish and squid, which aremajor food items for these groups. Ingestion ofplastic eventually kills them by causing internalinjuries if the plastic is sharp, or by starvationthrough restricting the movement of food, or byfilling the stomach and tricking the animal into

water (see also Section A (1) (b) above on bilgewater and ballast water). As they weather, plasticsbreak up into ever smaller pieces down to the sizeof sand grains. These minute particles are foundin sediments and in suspension in seawater,where they resemble edible plankton, leading filterfeeders and other organisms to consume them,by which they enter the ocean food chain. Theiringestion can concentrate any plastic-associatedtoxicants and/or adversely affect the consumersthemselves. Plastics adsorb and concentratePOPs (e.g., DDT, PCBs) and PAHs.

Nurdles – also known as mermaids' tears ormicro-plastics – are plastic pellets typically under5 mm in diameter and are a major component ofmarine debris. They form, inter alia, by thephysical weathering of larger plastic debris.Nurdles strongly resemble fish eggs, a foodsource for many organisms. The existence ofmicro-plastics and their potential impact on themarine environment is receiving increasingattention as evidence of their adverse

THREATS AND EFFECTS

Plastic pollution on a beach. © Maleen/Marine Photobank


thinking it is full. Sub-lethal effects includemalnutrition, which can affect reproductive fitnessand long-term survival of the population. They canalso become trapped in, among others, plasticropes, nets, bags, bait box bands, ‘six-pack’ andother rings used to hold cans together, wherethey will soon die from strangulation, suffocationor starvation, or by being eaten by predatorstaking advantage of their inability to escape.

Some 70% of marine debris will eventually sink tothe seafloor, where it is regularly observed inbenthic surveys at all depths. Plastic is alsoincreasingly found on the seabed, at all depths,often in the form of plastic bags. Here they form abarrier to the movement of benthic organisms,nutrients and gases in and out of theseafloor/water column interface, and, wherepresent, sediments. They can also cover hardand soft substrata and make them unsuitable forsettlement, by for example sessile filter feeders,and for foraging by deposit feeders. See alsoSection A (1) (c, f) on cargo and garbage, andChapter 2 on fisheries threats.

4. Overflight

Aircraft emissions can directly and indirectlypollute marine ABNJ and harm marineecosystems through their contribution to globalclimate change. Dumping of certain wastes is stillallowed from aircraft and this can place seamountecosystems at risk if done over their location (seeSection B (4) above on dumping for associatedthreats and effects). Noise from low-altitude flightscan have harmful effects on seamount-associatedspecies and their habitats (see also Section A (6)on noise). Increasing global air traffic heightensthe risk of pollution and contamination from planewrecks. (See also Section A (1), (3-5); although

focused on shipping, the threats from and effectsof the substances and activities described thereinremain applicable even when the vector is anaircraft rather than a vessel.)

5. Radionucleides

These substances have very long half-lives andcan be carcinogenic and mutagenic. Plutonium-239, used in reactor fuel and atomic weapons,has a half-life of some 24,000 years and is themost toxic. Cesium and strontium are also found.Nuclear weapons-testing has been the largestsource of radionucleides to the sea, mostlythrough fallout from the atmosphere. Othersources include operational discharges fromnuclear power facilities and reprocessing plants,remobilization of contaminated sediments, andradioactive waste dumping. Long-distancetransport by currents has placed radionucleideseverywhere in the marine environment. They canadsorb on particles that settle on the seabed andaccumulate in the sediments there, which canbecome 50 times as radioactive as the overlyingwater column, with particularly adverse effects onbenthic species. (See also Section B (4) above ondumping.)

A number of phytoplankton species canconcentrate radionucleides to levels that canexceed those in the water column up to 200,000times. In both cases they can enter the foodchain. Radionucleide contamination has beendetected in the tissues of marine mammals,seaweed, oysters and mussels. In addition to itsdeleterious effects on the viability of thecontaminated organism, radionucleides cancause genetic damage and thus also affect latergenerations.

THREATS AND EFFECTS


The existence of uncertainty and risk in othersectors is not treated as a reason for notdeveloping responsible actions accordingly.Indeed the opposite is more usually the case, ofwhich the insurance and re-insurance sectorsand, in the shipping sector specifically, P&I clubs,are well-known examples. Uncertainty is an eventwith unknown probability. Risk has been definedas statistical uncertainty, that is, an event with aknown probability. Most environmental problemssuffer from both. At present, and despite thegrowing use of the precautionary principle, theinability to characterize risk and uncertainty in theenvironmental context has hampered efforts toprotect the environment. Obtaining moreknowledge of seamount ecosystems andbiodiversity will not remedy this situation.

The priority knowledge gap in this context is theneed for a robust mechanism to improve thedetermination and quantification of uncertainty andrisk attendant on activities in or affecting themarine environment, such that commercially andenvironmentally responsible actions to addressthe threats of these activities to marine biodiversityand ecosystems can be developed. An open-ocean seamount ecosystem would provide apromising initial framework within which to designand test such a mechanism (see also Part IV).

It is not fully appreciated how much knowledgeis already available about the effects of humanactivities on marine ecosystems and marine

biodiversity, including those of seamounts. Neithershould the extent of our knowledge beunderestimated, especially when assessing thethreats, and their effects, to which humanactivities subject them. The precedingdiscussions and the list of references in Section VIrepresent only an illustrative sampling of thisknowledge, limited in this paper by space, timeand scoping constraints. That knowledge alreadysuffices to reasonably conclude that humanactivities are likely to have adverse effects onseamounts and their associated ecosystems andbiodiversity. Although it is not certain when and towhat extent these activities will have theseadverse effects, absence of certainty does notimply absence of knowledge. There will always beso-called ‘scientific uncertainty’, and rightly so,because knowledge can – and should – alwaysbe tested, improved and augmented.Nevertheless, for the purposes of this paper'sfocus on anthropogenic threats and their effects,and in the context of contributing to thedevelopment of a robust ecosystem-basedmanagement plan for seamounts, it is suggestedthat more research on seamounts and theirassociated ecosystems and biodiversity per se isnot, in this instance, the first priority.

III. KNOWLEDGE GAPS


Overexploitation entails over-extraction or overuseof any marine living or non-living resource, service,function or amenity that can thereby bediminished in quantity or quality such that theresource, service, function or amenity becomesunusable or disappears altogether. It is theoverarching threat of overexploitation to seamountecosystems and biodiversity that is posed by theactivities described in the present paper, shouldany of them occur to excess – the definition ofexcess varying with the activity. Overexploitationcovers the unsustainable extraction of livingresources, and in that context it is the principaloverarching threat to seamount ecosystems andbiodiversity.

The LOSC (including the implementing agreementon straddling and highly migratory fish stocks)does not define overexploitation, but LOSC Art.61 (2), for example, treats it specifically as a threatthat "endanger[s]" the "maintenance of livingresources". Overexploitation in ABNJ isaddressed, inter alia, by LOSC Arts. 116-120,which require conservation and management ofhigh-seas living resources and marine mammals,and by LOSC Art. 145, which requires protectionof the marine environment in the Area, i.e., theseabed in ABNJ.

The LOSC distinguishes between but does notdefine ecosystem or habitat. It providesspecifically for the protection and preservation of"rare or fragile ecosystems as well as the habitatof depleted, threatened or endangered speciesand other forms of marine life" (Art. 194(5)). TheCBD defines habitat as "the place or type of sitewhere an organism or population naturally occurs"(Art. 2; the CBD's definition of ecosystem isprovided and discussed above in Part I D).Habitats form part of ecosystems; thusdegradation of the former inevitably harms thelatter (and vice-versa). It is useful to maintain aconceptual distinction between adverse effectson habitats caused by materially or tangiblyphysical forms of habitat destruction anddegradation, such as those set out in Part II above(e.g., anchoring, cable/pipe-laying, grounding andshipwreck, mining, shading, washes and wakes,and the adverse effects on habitats of the otherthree overarching threats). However, when it isconsidered that the sheer quantitative removal

IV. ANALYTICAL SUMMARY

The threats set out in Part II to seamountbiodiversity and ecosystems fall into one ormore of the following four overarching

categories:

1. Pollution;

2. Habitat destruction, degradation andfragmentation;

3. Overexploitation; and

4. IAS.

As it does with the concepts of ecosystems andbiodiversity (see Part I D above), international lawprovides definitions of or conceptual approachesto these overarching threats that are helpful inassessing the potential of the activities listed inPart II above to harm seamount biodiversity andecosystems.

The definition of pollution in the LOSC isparticularly useful in that it applies to the marineenvironment as a whole, including ABNJ, and isboth comprehensive and precautionary: "[T]heintroduction by man, directly or indirectly, ofsubstances or energy into the marineenvironment, including estuaries, which results oris likely to result in such deleterious effects asharm to living resources and marine life, hazardsto human health, hindrance to marine activities,including fishing and other legitimate uses of thesea, impairment of quality for use of seawater andreduction of amenities” (Part I, Art. 1 1. (4)). TheLOSC usefully distinguishes between pollutionand the other three overarching threats, but doesnot define any of the latter.

Nevertheless, Art. 196 of the LOSC brings theuse of technologies and the intentional oraccidental introduction of IAS (i.e., ‘alien or newspecies’) within the concept of marine pollution,thus complementing LOSC Art. 1 (4). Note therather prescient inclusion of 'new species', whichmay become particularly relevant as geneticengineering of organisms gathers momentum.The inclusion of 'use of technologies' coversactivities designed for climate-change mitigation,such as the stimulation of artificial upwelling,marine cloud formation, and CCS (see Part II B (8)above on ocean-based climate-changemitigation), as well as land-based activities.


a minor additional stress triggers a whole-scalecollapse. The collapse in 1994 of the GrandBanks fishery is an instructive and soberingexample.

A major conclusion of the Millennium EcosystemAssessment is that the occurrence of tippingpoints in the marine environment is at presentunpredictable. This is another consequence of theknowledge gap identified in Part III. All the activitiesset out in Part II above already, to a greater orlesser extent, occur throughout, andconcomitantly threaten, the oceans. Many of theiradverse effects (there may be yet more than weknow) on the marine environment, its ecosystemsand biodiversity are known and evident. The scaleof the cumulative anthropogenic burden nowbeing placed on the oceans may already be sogreat that there may no longer be anascertainable threshold of human-induced threatsand effects on these ecosystems from which,once breached, they could still recover. Thissituation is likely to be applicable to seamounts aswell, and even, or perhaps especially, to thoseseamounts that are far from land in ABNJ.

Seamount ecosystems are considered to beparticularly fragile and vulnerable to anthropogenicthreats. The range of activities set out in Part II isextensive enough and their adverse effects onother ecosystems, if not on seamountsthemselves, are sufficiently well known that itwould be reasonable to surmise that all aspects ofthe seamount's ecosystems and biodiversitycould be placed at risk if these activities were tooccur in the vicinity of seamounts. Any additionalor new activity, or the intensification of an ongoingactivity, could even become the tipping point forthe collapse of a seamount ecosystem. Atpresent an objective comparator of the threatsand effects associated with the activities listed inPart II in this regard is lacking. This would beprovided by a mechanism to improve thepredictability of the tipping point trigger(s) or, asproposed in Part III above, to improve thequantification of the risks thereof for seamountecosystems.

from a habitat even of a single species can alsocause habitat degradation or destruction (as wellas overexploitation) – as can debris, light, noise,temperature, particles, pollution, etc. (see Part IIabove) – the distinction becomes difficult tomaintain at an operational level.

Although the detailed interaction – feedbackloops – among this quartet of overarching threatsis poorly understood, it is apparent from Part II thatthese threats usually overlap in, as well asexacerbate, their individual deleterious effects onmarine ecosystems, biodiversity and environment,including seamounts. It is highly likely that theirdetrimental effects are synergistic and cumulative.Moreover, it is becoming increasingly evident thatall marine ecosystems and habitats are essentialto all marine species at some point in their lifecycle. Therefore, at the operational level, marineecosystems and habitats are no longer usefullydistinguishable inter se or separable from theocean basin as a whole, if the objective is toeffectively protect them. Consequently, thefundamental, cumulative and synergistic effect ofthe other three overarching threats is to degrade,fragment and destroy habitats and ecosystemson an oceanic – that is, basin-wide – scale.

The concepts of assimilative or carrying orregenerative or absorptive capacity of anecosystem, which – at least as far as the ocean isconcerned – were assumed in humanexpectations to be almost infinite, are obsolete.Furthermore, ecosystem change in response tothreats is often neither linear nor gradual. It tendsto occur abruptly or accelerates once a thresholdis crossed. This threshold is called the tippingpoint. After the tipping point has occurred,recovery or rehabilitation of the resource, thehabitat, the ecosystem, is virtually impossible.Even if it were possible, it would be prohibitivelyexpensive. The marine environment is particularlysusceptible to tipping points. This vulnerability tocatastrophic, irreversible changes in structure andfunction is related to a history of multiple,interacting anthropogenic threats and their effectsthat may seem to cause ‘only’ ‘small’ incrementalchanges, but which in fact decrease resilience toenvironmental changes to such an extent that only

ANALYTICAL SUMMARY


Seamount biodiversity and ecosystemsappear to be "heir to a thousand [un]naturalshocks", to paraphrase Hamlet, whose

gloomy outlook finds some justification whenapplied to seamounts. They are already subject tochronic stresses both from shipping and fromnon-shipping activities that have global effects.Superimposed on these chronic stresses are thestresses from potential, emerging and actualactivities for which shipping serves primarily as aplatform; these additional stresses can be acuteand become chronic. None of the activitiesoperate in an otherwise pristine and unstressed(threat- and effect-free) environment. They canand often do interact, with cumulative andsynergistic adverse effects on the seamountenvironment, which is all the more worryingbecause the details of the interactions are poorlyunderstood. Therefore none of the activitiesshould be considered in isolation in assessing itspotential consequences for seamount biodiversityand ecosystem health. Pollution, overexploitation

and IAS essentially combine to degrade, if notdestroy, ecosystems, and they operate on anoceanic – that is, basin-wide – scale.

Seamount ecosystems are particularly fragile andvulnerable to anthropogenic threats and hence totipping points. Any additional or new activity, orthe intensification of an ongoing activity, couldbecome the tipping point for the collapse of aseamount ecosystem. An objective comparator ofthe threats, effects and their interactionsassociated with the activities in this regard islacking. This fundamental knowledge gap wouldbe filled by a mechanism to improve thepredictability of the tipping point triggers and toimprove the quantification of the interactive risksthereof for seamount ecosystems and biodiversity.Otherwise, the sheer multiplexity of the effects ofanthropogenic activities on seamount ecosystemsand biodiversity are unlikely to be manageable. AsHamlet said: "When sorrows come, they comenot single spies, but in battalions."

V. CONCLUSIONS


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1 A Taylor column is a result of the Coriolis force, which causes moving objects on the surface of the Earth to appear to veer to the right in thenorthern hemisphere, and to the left in the southern. Rotating fluids that are perturbed tend to form columns parallel to the axis of rotation,called Taylor columns. A rotating fluid has a specific kind of rigidity and no longer acts quite like a fluid. An opposing view holds that open-ocean waters are normally nutrient deficient, and nutrients released from open-ocean aquaculture operations may increase wild production inadjacent areas. See: http://onf-ocean.org, http://sydney.edu.au/science/usims/ocean_technology/research/nourish.shtml,http://sydney.edu.au/science/usims/ocean_technology/research/kenya.shtml and http://www.subsistencefishingfoundation.org.

seamounts are unable to reach deep water andinstead become prey to pelagic and benthic-feeding seamount-associated predators. Manybenthic invertebrates found on seamounts aresuspension- or filter-feeders which are adapted tocapture this food source; they include stonycorals, gorgonians, black corals, sea anemones,sea pens, hydroids, sponges, sea squirts(ascidians) and crinoids. Fish and non-benthicinvertebrates also exploit this food source: Rogers(2006) notes “…reports of extremely denseshoals of lantern fish, mysid shrimps and squidthat feed above seamounts at night but which liveclose to the sides of seamounts during the day.These species appear to feed on verticallymigrating oceanic plankton that maybe becometrapped above the seamounts. In turn, they form afood source for larger, commercially valuablespecies of pelagic fish such as sharks, rays, tunaand swordfish”.

There is thus a regular inflow of prey to seamountareas, although in many cases this is periodicrather than constant. The nutrient and food supplyallows seamounts to attract and maintain largepopulations of commercially useful fish and otherorganisms, some of which may be permanentand others transitory. Seamounts have beenshown to concentrate pelagic plankton and toattract aggregations of fish, birds and mammals.

The fish aggregating effects of seamounts havelong been noted by the commercial fishingindustry, and many seamounts are or have beenextensively exploited. Some 80 fish species arecommercially harvested from seamounts,including orange roughy, oreos, rockfish andalfonsino. Lobsters, deep-water corals and othercommercially valuable species are also targetedby specialized fishing operations.

A. Introduction

Sections II (B) and II (C) of companion Volume 1,‘Overview of Seamount Ecosystems andBiodiversity’, provide descriptive information onthe deep-water fisheries of Indian Oceanseamounts. This chapter presents a generalizedaccount of threats to seamount ecosystems bythese and other types of fishing operations. Someof the information presented here originates fromstudies undertaken or data obtained from outsidethe Indian Ocean, but whose findings are relevantto the region.

Interactions between seamounts and underwatercurrents, as well as their elevated position in thewater, attract plankton, corals, fish and marinemammals alike. Seamounts create complexcurrent patterns that can influence the behaviourand distribution of the marine life on and abovethem. Interactions between currents andtopography on seamounts include semi-stationaryeddies (Taylor columns)1, internal wave reflection,tidally induced currents and eddies, trappedwaves, and eddies shed downstream. Isothermsare also uplifted over seamounts, resulting in theintroduction of nutrients into surface waters whereplankton development is often nutrient-limited. Dueto these strong localized currents and upwellings,the biomass of plankton, including fish larvae, isoften high over seamounts (Boehlert and Genin,1987).

The diurnal movement of planktonic organismsthat makes up the deep-scattering layer (DSL)also contributes to high seamount productivity.The DSL rises in the water column during thenight, during which time it is horizontallytranslocated by ocean currents. DSL organismsseek to descend again in the early morning, butthose that are transported to the vicinity of


CHAPTER 2 – FISHERIES AND AQUACULTUREAuthor: Garry Preston

I. FISHERIES


Depletion of many inshore and shelf groundfishstocks in the 1990s encouraged fisheries toexpand into deeper water and, in particular, toseamounts. Since the 1970s, advanced geartechnology has enabled fishing in deeper watersand on small, steep and rough seamount flanksthat were previously too difficult to fish (Pitcher etal., 2010). Kitchingman and Lai (2004) used mid-resolution bathymetric data to estimate thenumber of seamounts globally (around 14,000).Based on this information, Guinotte (undated)estimated the number of high-seas seamounts inthe Indian Ocean to be 1,203, of which 268 couldbe fished using currently available technology, theother 935 too deep (over 2,000 m) to fish at thepresent time. The same author noted that thereare 39 seamounts within the proposed SIODFABenthic Protected Areas (see Section II (C) of

companion Volume 1 for description), of which 15are fishable and 24 are too deep to fish usingcurrent technology.

The main types of fishing operation practised onseamounts can be categorized as:

m deep-water fisheries, which involve directcontact between the fishing gear and thebenthos of the seamount: bottom-trawling,bottom-set gill-netting, bottom longlining, trap-fishing, dropline fishing and coralharvesting; and

m surface and mid-water fisheries, in which thegear does not (intentionally, at least) come intophysical contact with the seamount benthos:mid-water trawling, longlining and purse-seining.

FISHERIES

Figure 1: Circulation around a seamount summit (not to scale). The circular flows run clockwise,decreasing in strength with height off the bottom. There is a strong lateral flow outward near the

seamount summit, with weaker inward flows higher up. Vertical currents are strongly downward nearthe centre and weaker and upward near the periphery. Larvae caught in this flow pattern might easily

complete their development near the seamount summit. (From a study on currents and larvalsettlement at Fieberling Guyot, a Pacific seamount, by Mullineaux, L.S. and S.W. Mills (1997), cited athttp://oceanexplorer.noaa.gov/explorations/03mountains/background/larvae/media/circulation.html)

especially those outside the jurisdiction of currentmanagement agencies, is one of the mostworrying developments in recent years.” Seamount fisheries typically exhibit a boom andbust sequence, crashing within about ten years oftheir initial development. This was the case withthe orange roughy fisheries off New Zealand,Australia and in the Atlantic, the pelagicarmourhead (Pseudopentaceros wheeleri)fisheries over seamounts in international waters offHawaii, and the blue ling (Molva dipterygia)fisheries in the North Atlantic. As seamounts arerapidly depleted, the continued existence of thefisheries on them depends upon the discovery ofunexploited seamounts with large fishconcentrations.

The species targeted by seamount fisheries oftenhave a low overall abundance, but may aggregateat seamounts as certain stages of their life cyclestrategy, such as for spawning. In many casesthey are long-lived, slow-growing, late-maturing (atabout 30 years) and have low reproductivepotential. If fished out, it could be decades beforethese localized stocks recover, particularly as theymay have limited exchange with other seamounts.

Unregulated small-scale fishing can also disturbthese sensitive environments, as has beendemonstrated by the decline of importantseamount fish stocks exploited by small-scalehandline and bottom longline fisheries in theAzores and in Tonga. However Pitcher et al.(2010) state: “Small-scale artisanal fisheries usingless harmful fishing gear, spatial closures, and lowcatch levels provide an attractive model forimproved seamount fishery management thatcould foster the reconstruction of previouslydamaged seamount ecosystems.”

C. Physical damage to benthicecosystems

Bottom-trawling as a fishing method is widelycriticized among the fisheries management andconservation communities because of thedamage it causes to benthic ecosystems (see forexample Jacquet et al., 2010). Bottom-trawlingcan damage ecosystems by literally scrapingaway sections of seafloor and removing habitat-forming organisms and their associated

There have been surprisingly few studies ondeep-water fishing impacts, especially onseamounts, given the amount of fishingconducted on them in recent years (Pitcher et al.,2010). There are nevertheless serious ongoingconcerns as to the negative effects of fishing onseamount ecosystems, which relate primarily tothe following issues:

m Stock depletion. Seamount fisheries areusually boom-and-bust fisheries, in whichstanding stocks are quickly depleted byintensive fishing, after which the fishingoperation moves to a new seamount. Thereare well-documented cases of stock decline,for example with the orange roughy(Hoplostethus atlanticus);

m Physical damage to benthic ecosystemscaused by trawls and traps dragging acrossthe seafloor, or by entanglement of nets andlines;

m Alteration of pelagic, mesopelagic and benthicecosystems through the selective removal oftarget species and associated by-catchspecies; and

m Other impacts that may be caused bydiscards of unwanted or excess catch, noisedisturbance by sonic equipment used infishing, ghost fishing by lost or discardedfishing gear, and issues specific to certainfisheries, such as those for deep-water corals.

These impacts of fishing operations are discussedin more detail in the following paragraphs. Moregeneralized impacts caused by fishing vesselsthemselves are similar to the impacts of shipping,described in Chapter 1 (Section II (A)).

B. Stock depletion

Over-fishing of coastal stocks has created newpressures for the fishing industry to locatealternative fishing grounds. In particular,seamounts are relatively newly targetedecosystems that have become increasingly fishedsince the second half of the 20th century. Watsonand Morato (2004) state: “Expansion ofcommercial fisheries into deep-water areas,

FISHERIES



communities. The ground gear used to protectthe deep-water trawl nets from damage on therough seafloor is large and heavy, and as well asthe obvious direct impacts caused by physicaldisruption, there are also indirect effects such assediment re-suspension and mixing (Pitcher et al.,2010) and attraction of predators and scavengers.Seamount topographies, along with navigationtechnology, result in a large number of trawl towsover a relatively small area, and with the heavytrawl gear used in the fisheries this producesintense local disturbances (Smith, 2002). Suchmassive removal of natural and structuralcomponents of the ecosystem has highly negativeconsequences for seamount biodiversity.

Sessile fauna such as deep-water corals, whichform reef-like structures on the summits andupper flanks of deep-water seamounts, areparticularly vulnerable to damage by trawlingoperations. The bushy tree-like form of manyseamount invertebrates, which are often adaptedto filter-feeding, makes them easily prone tobreakage by ground gear. These animals formbiogenic habitat for many other species, and maybe slow-growing and hundreds of years old, soany recovery from impact is slow. Studies of theby-catch taken in orange roughy fisheries clearlyshow that habitat-building corals such asSolenosmilia variabilis are removed by trawling(Anderson and Clark, 2003). This has beenquantified in various studies, including acomparison of the catch composition of corals insix trawls from unfished seamounts (total coralcatch 3,000 kg) and 13 trawls on fishedseamounts (5 kg coral) on the northwest ChathamRise of New Zealand (Clark et al., 1999).

On Tasmanian seamounts, Koslow and Gowlett-Holmes (1998) recorded major impacts onbiodiversity within a few years of the developmentof the orange roughy fishery. On heavily fishedseamounts (more than 1,000 individual trawloperations known to have occurred) reefaggregate had been removed or reduced torubble, the invertebrate biomass was 83% lower,and the number of species 59% lower than onlightly fished seamounts (10-100 trawls). Intensefishing effort over a sustained period of time isclearly deleterious, but even ‘light’ trawling’ can

have significant and perhaps irreversible effectson the habitat and ground cover provided bybenthic organisms. For example, although trawlingmay not completely remove coral, repeateddamage to coral colonies over time can reducetheir size to a point where sexual reproduction ofdispersive larvae is no longer possible (Rogers,2004).

The wide but discontinuous distribution ofseamounts creates unique problems for thedispersal and recruitment of seamount-associatedfish and invertebrates, with potential loss of larvaeand juveniles from the local environment. Differentspecies have evolved different strategies fordispersal from and recruitment to seamountenvironments. Even amongst the commerciallyimportant teleosts, some species, such asarmorhead, alfonsino and oreo, have extensiveocean-wide pelagic juvenile dispersal and recruitto distant sea mounts, while orange roughy havelimited dispersal with a short larval stage andassumed benthic juveniles. These differentdispersal patterns are reflected in levels of geneticdifferentiation between populations, with lowdifferentiation in oreo and higher differentiation inorange roughy. Species with narrow dispersalcapabilities will be more vulnerable to localizeddepletion (Smith, 2002).

Many of the commercially important seamountfishes have ocean-wide distributions, but a highdegree of endemism of both invertebrates andsmall benthic fishes has been reported amongseamounts. Around 15% of the 597 species,mainly megafauna, that occur on seamountsglobally are considered to be endemic (Wilsonand Kaufman, 1987). Some studies on Australianseamounts indicate much higher levels ofendemism (United Nations, 2006). For example,in just one expedition to the Tasman and CoralSeas in the South Pacific, scientists reported that16-36% of the 921 species of fish and otherbenthic macrofauna collected on 24 seamountswere new to science (United Nations, 2004). On14 seamounts off southern Tasmania 24-43% ofthe species sampled were new to science and16-33% were endemic (Koslow and Gowlett-Holmes, 1998). Low species overlap was foundbetween seamounts in different portions of theregion, suggesting that these seamounts function

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of fish, as well as invertebrates (lobsters, squid,mysid shrimps), some of which may havecommercial value, others of which will bediscarded as ‘trash’. In New Zealand, trawl by-catch from seamounts included large epibenthiccnidarians (black corals, true corals and sea fans),echinoderms (starfish, sea lilies and brittle-stars),arthropods (stone crabs and true crabs) andmolluscs (gastropods, octopus and squid), manyof which were new to science (Smith, 2002). Inthe Indian Ocean, trawl by-catch may beexpected to include a wide range of benthicinvertebrates and fish, as well as occasional takesof sensitive or vulnerable species such as benthicsharks. Trawl fisheries in general are notorious fortaking and discarding large amounts of by-catch.Shrimp fisheries in particular may have by-catchrates which exceed the catch of target species byup to 20:1, with an overall (global) average of5.7:1 (Clucas, 1997). Trawling for finfish produces

as islands or chains, with importantconsequences for speciation (Baker et al., 2001).Given the relatively high levels of endemism ofseamount faunas, especially those associatedwith cold-water coral reefs, coupled with thesomewhat limited dispersal ranges of somespecies, it is likely that trawling activities havealready destroyed many benthic seamountcommunities, with as yet undetected impacts onthe wider ocean ecosystem (Rogers, 2004).

The physical impacts of other deep-water fishingmethods are less dramatic than those associatedwith trawling, but still have the potential to causeunwanted impacts. Dropping of traps or pots forlobsters or fish is prospectively a technique thatcould cause cumulative damage to habitat-forming corals over time, but is not known to bepractised to any great degree on seamounts atthe present time. Bottom-set gill-nets, demersallonglines and hand-line gear used for bottomfishing all carry lead weights that can causedamage to corals during the setting and haulingoperation, or if dragged across the seafloor bycurrents. If the gear becomes tangled then effortsto free it by brute force can lead to additionalbreakage of corals and damage to other benthicorganisms. However, the practicalities of operatingthese types of fishing gear mean that all but theshallowest seamounts are essentially unfishable atthe present time. The UN (2006) states that “whilethere is some evidence to suggest that bottom-set longlines, bottom-set gillnets, pots and traps(including when ‘ghost fishing’) all may beimpacting the deep-sea, bottom trawling anddredging appear to be having the most obviousdisruptive impact due to their widespread use andtheir contact with the bottom”.

D. Target species and by-catch

All fisheries selectively remove certain speciesfrom the ecosystem they exploit, and thus by theirvery existence cause alterations to marinecommunity and ecosystem structures.

In the case of deep-water trawling, some of thecorals and other benthic organisms that arebroken by the physical action of the fishing gearwill be incidentally harvested as part of the catch.Trawl by-catch also includes various other species

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A fish skeleton caught in a ghostnet. © Sijmon de Waal/Marine Photobank


lower, but still sometimes significant, volumes ofby-catch.

Other fishing operations also exert their toll interms of by-catch. Pelagic and bottom longlines,as well as handlines and baited traps, all take awide variety of fish species, almost invariably apexpredators because of their use of bait. Purse-seine fishing in the Indian Ocean targetssurface-swimming tuna schools, but there isusually an incidental catch of non-target speciesthat includes other finfish, sharks and,occasionally, sea turtles and marine mammals.The selective removal of these species hasecosystem impacts through its effects onpredator-prey relationships, and possibly othermechanisms, which at present are poorlydocumented.

E. Discards

It is worth making the distinction between ‘by-catch’, meaning the incidental capture ofnon-target species, and ‘discards’, which meanscatch that is unwanted and usually thrownoverboard while at sea. Not all by-catch isdiscarded – some has commercial value and isretained (e.g. crayfish and some large fish speciessometimes taken in prawn trawls). Conversely, notall discards are by-catch – sometimes some ofthe target species are thrown overboard in orderto make space in the fish holds for more valuablecatch, or to comply with quota requirements orother management measures. ‘High-grading’ is aparticular category of discarding, whereby low-value target species (e.g., small size classes) areretained at the beginning of the fishing trip butmay be discarded later if a good catch of largerfish is taken and storage space becomes limited.

Discarding usually takes place at the conclusionof each fishing operation, while the catch is beingsorted and processed or stowed. However, this isnot always the case – high-grading involvesthrowing overboard fish which had previouslybeen retained, but which are now beingdiscarded in order to free up storage space formore recently caught higher-value species or sizeranges. High-grading may involve discarding largevolumes of already-frozen catch from freezerwells, sometimes along with the brine (usually a

strong calcium chloride solution) in which it hasbeen frozen. Discarding may thus involve throwingoverboard several tens of tonnes of fresh orfrozen catch, sometimes along with freezer brine.

There is little or no data on the geographicaldistribution of discards from fishing operations,but it seems likely that discarding must occurabove or in the vicinity of seamounts. Trawlersoperating close to seamounts almost certainlydiscard in their vicinity. Because seamounts areknown to act as an aggregation point for tunaschools, purse-seiners also regularly search andfish these areas, and may discard in their vicinity.

The impacts of discarding on or aroundseamounts are unknown, but the practice may bepredicted to have consequences similar to thoseobserved in coastal areas: attraction ofscavengers, putrefaction of decaying fish on theseafloor, and consequent impacts on benthicfauna through deoxygenation, bacterial infectionand physical burial. In areas of strong currents,the impacts of the discarded product may beattenuated to some degree through dispersal, butdiscarding still represents a point source ofintense organic pollutants. As many seamountsare thought to have current systems which retainplankton and fish larvae, it might be expected thatpollution and putrefaction products may also beretained in the seamount vicinity rather than beingrapidly dispersed.

F. Ghost fishing

Several fishing methods utilize gear andequipment such as gill-nets, traps and pots thatmay continue to fish after being discarded or lost.This results in fish being removed from thepopulation as in a normal fishing operation,although they are not actually harvested. Mostfishing gears of this type will deteriorate over time,through tangling (in the case of gill-nets) orphysical breakdown (all types), causing thedegree of ghost-fishing to progressively diminish.The degree to which ghost-fishing is an issue onseamounts is not known but is thought to berelatively small. The primary fishing gears used onseamounts – trawls, purse-seines and longlines –involve active or baited gears which do notcontinue fishing after being lost or discarded.

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from military sources has been observed to causephysical damage, including internal bleeding, tocetaceans (Jasney et al., 2005).

Recent technological advances have seen thedevelopment of sonic deterrent and monitoringdevices for use on longline fishing gear. Theseinclude: sonic deflectors (passive devices forattachment to the longline) which confuse marinemammals and reduce depradation of longlinecatches by pilot whales and other cetaceans; andsonic monitoring buoys, which alert the longlineoperator to the presence of cetaceans within 80km of the fishing vessel, so that the vessel canavoid deploying the fishing gear in these areas.While these devices are intended both to reducefishery losses through cetacean depradation andto avoid interactions between fishing gear andmarine mammals, their broader effects or impactsare unknown (Anon, 2010).

H. Harvesting of genetically uniqueresources

Current threats to the genetic diversity ofseamount populations are principally from over-fishing or destructive fishing activities, asdiscussed above (see Sections I (B) stockdepletion and I (C) physical damage to benthicecosystems). Reduction of population orecosystem diversity may result in a correspondingdecrease in genetic diversity in the populations orecosystems concerned.

Because of their relatively high levels ofendemism, as well as the large number of newspecies continually being discovered there,seamounts undoubtedly serve as a repository ofnew or unfamiliar genetic material. Prospecting forgenetic resources on seamounts (for purposes offish stock improvement, identification ofbiochemicals with new properties, or geneticengineering) is not widespread at present, butmay increase in the future. Development of suchactivities needs to take place in a manner that isboth environmentally responsible and recognizesthe rights and authority of resource owners or, inthe case of the high seas, broader public interestin common property resources (Greer and Harvey,2004).

G. Noise and acoustic devices

Most modern fishing vessels employ acousticdevices (echo-sounder and sonar) to monitorwater depth, bottom contour and composition,and to detect fish biomass, which is then targetedusing the fishing gear. Sonar devices are alsodeployed on the head-ropes and foot-ropes oftrawls to help the operator determine the distanceof the net from the seafloor and the gape of thenet’s mouth. Acoustic technology has been oneof the most important driving forces behind thedevelopment of the modern commercial fisheries.

Fish finders and most commercial depth soundersoperate at high frequencies. Usually, but notalways, they project a lower power signal andhave narrower beam patterns and shorter pulselengths (a fraction of a second) than militarysonars. Fish-finding sonars operate at frequenciestypically between 24 and 200 kHz, which is withinthe hearing frequencies of some marinemammals, but above that of most fish. Globallythere are a great many recreational, fishing andcommercial vessels, most of which are fitted withsome sort of sonar. Usage occurs throughout theyear and both by day and night. Somehorizontally-acting fish-finding sonars work atfrequencies at the lower end of the ‘high-frequency’ range and are relatively powerful. ICES(2005) states that “the body of data currentlyavailable on the response of fish to sounds is notyet sufficient for developing scientificallysupportable guidance on exposure to sound thatwill not harm fish. Nor is it possible at present topropose detailed measures for mitigation of theimpact of sound”.

Active sonar may harm or interfere with thebehaviour of marine animals. Most marinemammals, such as whales and dolphins, useecho-location systems (sometimes calledbiosonar) to locate predators and prey. Activesonar transmitters can confuse the animals andinterfere with basic biological functions such asfeeding, mating and migration. Exposure to high-intensity noise can cause a reduction in hearingsensitivity (an upward shift in the threshold ofhearing) but this impact is unlikely from the typesof sonar used by fishing vessels. Intense sonar

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I. Deep-water corals

Small, specialized dredge or ball-and-net fisheriesfor deep-sea corals exist in a small number oflocales. The fishing methods used break andcapture pieces of pink, black or other deep-watercorals that can be used in making jewellery. Theseare generally artisanal or small-scale operationssituated in areas where there is a well-developedlocal tourist market that can absorb the product. Itis not known whether fishing operations forprecious corals take place on Indian Oceanseamounts. If they do they are likely to be smalland relatively unimportant.

Of far greater concern than targeted fishing forprecious corals is the incidental damage done bybottom-trawling for fish on seamounts. As notedin Section I (C) above, large areas of deep-watercorals are known to have been destroyed bybottom-trawling operations, and this is continuingin an indiscriminate manner. Clark et al. (2006)propose measures to improve knowledge andmanagement of coral populations on seamountsthrough more comprehensive data reporting fromcommercial fishing fleets, stronger enforcement ofcompliance requirements, strengthening ofregional fisheries management organizations andimproved dialogue between science, industry andcivil society. Roberts and Hirshfeld (undated) gofurther, demanding a prohibition of trawling incurrently untrawled areas potentially containingcoral communities, closure of some areascurrently damaged by trawling, restoration ofdamaged areas, and more severe penalties fornon-compliance by fishing vessels.

J. Marine aquarium trade

Almost all marine aquarium species are takenfrom the wild, with few examples of captivebreeding. Tropical coral reefs are the mostimportant source of specimens for the aquariumtrade – mainly fish, including seahorses, the coralsthemselves, and others such as anemones,starfish and giant clams. Collection of ornamentalspecies also occurs in other areas, includingtemperate oceans and freshwater bodies. In mostcases collection of ornamental species is done bysmall-scale fishers, often using diving gear, inlabour-intensive fishing operations.

As far as is known, there is currently no significantcollection of ornamental species for the aquariumtrade from seamounts, due to their depth andrelative inaccessibility. In the event that thisindustry does ultimately develop in seamountareas, the threats will be similar to thoseexperienced in areas where the industry alreadyexists, namely: over-fishing, use of destructivefishing practices and (possibly) populationmodification through sex-selective harvesting ofkey species (Wabnitz et al., 2003).

K. Sports/recreational fishing

Recreational fishing on seamounts is limitedprimarily to ‘blue-water’ sports fishing for largepelagic apex predators such as marlin, tuna,dolphin fish and sharks. These are the samespecies as those targeted by longline fishingoperations. Sports fishing is often viewed as a‘greener’ way of using this resource, given thelarge economic multiplier that applies per fishcaught: the returns on longline-caught fish may beof the order of a few dollars per kilo, whereassports fishing is often associated with touristspending on associated services and supplies.Development of locally-based sport-fishingindustries is a target of many small-islanddeveloping States, including those in the IndianOcean, and sport-fishing clubs exist in all westernIndian Ocean countries. Those seamounts withina few tens of kilometres from the shore are naturaltargets for sport-fishing activities because of theirfish aggregating effects, described above.

The impacts of recreational fisheries on IndianOcean seamounts are relatively limited: there islittle or no use of destructive fishing gear ortechniques, little or no discarding, and catchesare orders of magnitude lower than those ofcommercial or industrial fisheries. Many sportsfishing operations, especially those that target thetourist market, operate a catch-and-release policy,so fishing mortality is limited. Selective removal ofapex predators may have unknown ecosystemimpacts, but this is likely to be minusculecompared to those arising from longline fishingoperations. Even with significant furtherdevelopment of this industry, it will pose far less ofa threat to seamount ecosystems thancommercial fishing.

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some experimentation with offshore shellfishculture on suspended ropes and longlines, andoffshore seaweed culture may also be considered(Borgatti and Buck, 2004).

Current research programmes are focussing onidentifying appropriate farming species anddeveloping culture techniques, including speciesselection, egg/larval production systems andnutritional/dietary requirements. Species currentlybeing studied for possible culture include halibut,haddock, cod, flounder, blue mussels, black seabass, mutton snapper, cobia, yellowtail snapper,amberjack, deepwater snappers, corvine,mahimahi, red drum, tuna and striped bass. Otherresearch topics being investigated include:

m hatchery culture technologies;

m designs for automated feeders;

m culture of new species;

m identification and control of diseases;development of cages and husbandrytechnology for rough water environments;

m identification of alternative food sources;

m information on nutrition requirements;

m definition of carrying capacity of offshorewaters;

m development of appropriate mooring systems;

m development of drifting and self-poweredcages; and

m development of environmental monitoringsystems and technology (Upton and Buck,2010).

Proponents of open-ocean aquaculture and manyenvironmental groups suggest that open-oceanfinfish aquaculture systems may encounter similar,but fewer, environmental concerns than thoseexperienced by near-shore aquaculture systems.This is in part due to the assertion that dissolvedand particulate waste products and excess feedmay be assimilated and recycled more efficientlyin the open-ocean environment. However, thescope of any effects may vary greatly dependingon the technique, location, size/scale ofoperation, and species raised. In addition, OOAinvolves less control over organisms and thesurrounding environment than do inshore and

A. Introduction

Open-ocean aquaculture (OOA) refers to therearing of marine organisms under controlledconditions in exposed, high-energy oceanenvironments beyond significant coastal influence.Proponents of OOA believe it is the beginning ofthe ‘blue revolution’ – a period of broad advancesin fish culture methods which will lead toincreased production, take pressure off wildstocks, avoid user conflicts, enhance recreationalfishing opportunities and create new jobs. Criticsraise concerns that such farms could harm theenvironment, put native fish at risk, pollute oceanswith fish waste and excess food, and havenegative impacts on existing commercial fisheries.The economics of many OOA systems have yetto be tested and in some cases it is hard to seehow they could be profitable or cost-effectivegiven the rigours and challenges presented by theopen-ocean environment. In particular, greatdistance from shore significantly increases theinvestment requirements and costs of servicingoffshore aquaculture platforms (Kite-Powell,2008). There are also concerns that OOAactivities will threaten existing jobs and livelihoodsbased on wild fisheries. Recent US plans topermit 5-20 deep-water aquaculture operations inthe Gulf of Mexico have been criticized by morethan 100 environmental and fishing organizations.These potential environmental and economicimpacts and associated controversies haveprobably contributed to slowing the expansion ofthis sector.

The technology for OOA is relatively new andexperimental or, in some cases, yet to movebeyond the drawing board. Actual or proposedfarming systems include cages, net-pens andlongline arrays that can be free-floating, securedto a structure, moored to the ocean bottom ortowed by a vessel. Research and commercialOOA facilities are in operation or underdevelopment in Australia, Chile, China, France,Ireland, Italy, Japan, Mexico, Norway and theUSA. Many of these are trialling OOA technologyin shallow or protected coastal waters prior to full-scale deployment in an oceanic environment, andmost currently operating commercial facilities arein near-shore waters where they use cagesmoored to the ocean bottom. There has been

II. AQUACULTURE


land-based aquaculture, and may present feweroptions to rectify environmental problems whenthey do arise. Critics of open-ocean aquaculturehope that regulation of this emerging industry willbe stringent (Bridger and Reid, 2001).

Essentially, OOA is in its infancy and, althoughthere are many pipeline projects, there are only afew actual operations currently in existence fromwhich to draw lessons and information. Thepotential outcomes of OOA are difficult togeneralize because of the diverse nature ofpossible operations and the lack of aquacultureexperience in open-ocean areas. Environmentalimpacts are thus not known with certainty,although based on information from other types ofaquaculture it can be speculated that they willinclude: the escape of fish, water pollution fromuneaten feed and waste products, use ofantibiotics and other animal drugs, alteration ofbenthic habitat by settling wastes, and the spreadof waterborne disease from cultured to wild fish(Bridger and Costa-Pierce, 2003). Another issue,specific to OOA, is the potential for impacts onmarine mammals and other sensitive species. Inthe event that OOA facilities ultimately develop inthe vicinity of seamounts, in the Indian Ocean orelsewhere, environmental threats or impacts arelikely to fall primarily into these categories, whichare described in more detail below.

B. Feeding and waste disposal

All fish currently proposed for OOA arecarnivorous, and farming of these speciesinvolves daily feeding with compounded feedscontaining fishmeal and fish oil. Aquaculture feedsare produced primarily from fish caught from wildstocks, supplemented to some degree withvegetable-based protein or other products. Threeor more units (by weight) of feed are required toproduce one unit of farmed fish; hence there is alarge amount of fish feed provided daily, much ofwhich is excreted by the fish as waste products.A small amount of feed may go unconsumed andfall through the bottom of the cage or net, OOAfacilities being open to the surroundingenvironment.

The degree to which this constant stream ofwaste is absorbed or attenuated by thesurrounding marine environment will depend onthe composition and health of the ecosystem andon current and water circulation patterns. If wastecannot be readily absorbed or attenuated, then alocal over-supply may develop of nitrates,phosphates and other chemicals found inbiological waste products. This may in turnpromote eutrophication and impact on theavailability of food and oxygen within theseamount ecosystem. In addition, solid wasteproducts may accumulate on the seafloor andresult in harmful effects on the benthos, causedby deoxygenation, putrefaction and bacterialcontamination2. Further local impacts may occur ifaquaculture operations on seamounts also begincatching fish locally to provide feed for farmedspecies, although this seems unlikely.

Another environmental concern is the use ofpharmaceuticals, antibiotics, growth-enhancingchemicals, other animal drugs, and antifoulingagents used on gear and enclosures in open-water environments. Drugs, some of which weredeveloped and approved for use in a contained orcontrolled environment, are often introduced tocultured fish in their feed. The unconsumed feed,and the metabolic waste from the fish feeding onit, pass through and out of the containmentsystem, where some of the artificial additives theycontain may be consumed by wild organisms.

Open-water culture of molluscan shellfish may bemore environmentally benign, as it does notusually involve feeding of the farmed animals.However, high stocking densities of filter-feedingmolluscs still produce large volumes of faecalmatter which, depending on local currentconditions, may result in solid waste pollutionproblems similar to those described for finfish.

C. Disease

Fish kept under intensive farming conditions aremore prone to epidemics of diseases or parasitesthan they are in the wild. This is because the fishthemselves are usually stressed and prone to

AQUACULTURE

2 An opposing view holds that open-ocean waters are normally nutrient deficient, and nutrients released from open-ocean aquacultureoperations may increase wild production in adjacent areas.


(sometimes in contravention of aquacultureregulations) to control disease and parasiteinfection. Because of the open nature of thecages or pens in which the farmed fish are kept,diseases and parasites can easily be transferredto fish in the wild, and there are numerous

infection because of overcrowding and unnaturalfeeding regimes; and the high stocking densitiesunder which the fish are kept provide idealconditions for infections to spread. Manyaquaculture operations use veterinary drugs in thefish food or applied directly in the water

AQUACULTURE

Open-ocean aquaculture. © Kydd Pollock/Marine Photobank


well-documented cases of this in regard to thesalmon-farming industry, where sea lice fromfarmed fish in cages have infested wild populations.(Disease may also spread from wild populationsto farmed fish: outbreaks of infectious hemato-poietic necrosis virus in farmed salmon have beenconfirmed to have originated from wild fish).

Another concern involves the spread of fish-bornedisease and genetic anomalies that couldpossibly occur if wild fish are exposed to orinterbreed with hatchery-raised fish. This issuemight arise if genetically modified or non-nativefish escaped from aquaculture facilities andinterbred with wild fish. Critics speculate that,since selectively bred and genetically modified fishmay grow faster and larger than native fish, theycould displace native fish in the short term (boththrough competitive displacement andinterbreeding), but might not be able to survive inthe wild for the long term. This is especially aconcern in US states such as California, Maine,Maryland and Washington, where geneticallymodified fish are banned within state waters butcould be grown offshore in federal waters. Arelated concern is the introduction of exoticspecies, such as Atlantic salmon in BritishColumbia. Escaped fish could be a problem inopen-ocean facilities battered by storms. Theexperience with salmon farming indicates thatescaped fish could easily be a problem, eitherthrough interbreeding with closely related nativespecies (genetic interactions) or throughcompetitive displacement of native species.Although management techniques at net-pensites are improving and modified cage designsbetter prevent escapes, closed containmentsystems may be the only way to address thisproblem. Problems with the transfer of sea licefrom salmon farms to wild salmon have beennoted recently.

D. Escapes

Escapes of fish are inevitable from a fish pen orcage floating in the open ocean, especially duringperiods of storms or rough weather. Concernsregarding escapes are threefold:

m Escaped fish may be of a species that is non-native to the seamount environment, but

which may adapt and become invasive, out-competing and displacing native species;

m Escaped fish could interbreed with closelyrelated native species, affecting the geneticintegrity of the local population; and

m Genetic anomalies in local fish populationscould occur if wild fish interbreed withhatchery-raised fish, especially geneticallymodified ones. Critics speculate that, sinceselectively bred and genetically modified fishmay grow faster and larger than native fish,they could displace native fish in the shortterm (both through competitive displacementand interbreeding), but might not be able tosurvive in the wild for the long term.

There are numerous examples related to coastaland terrestrial aquaculture in regard to each ofthese concerns.

E. Endangered and sensitive species

Since OOA facilities will be offshore andunderwater, possible harm or disturbance tomarine mammals and other wildlife are a concern.Experience has shown that dolphins and othermarine mammals do get entangled in fish farms.To address these concerns, current cage designsfor finfish avoid the use of small-diameter or looselines or loosely hung netting which could lead toentanglement of sea turtles and marine mammalsin net-pens and associated gear. Shellfish farmshave many ropes and longlines, and could bemore problematic.

Sonic devices are used by some aquaculturefacilities to keep certain types of nuisance animalsat bay, and these could harm marine mammals.Open-ocean facilities could potentially affect someendangered species, such as whales, as theymigrate, or could alter essential habitat forfeeding, breeding and calving. There could alsobe incidence of killing ‘problem’ animals, as hasbeen the case with salmon farmers killing sealsand sea lions. This might extend to otherpredatory animals such as sharks; great whitesharks, an endangered species, have found theirway into tuna farms in Australia on severaloccasions, for instance.

AQUACULTURE

of the deep ocean. With these drawbacks,“societal and political acceptance is likely to below” (Royal Society, 2009).

A number of university research projects and civil-society groupings are also investigating oceanfertilization. The Ocean Nutrition Foundation3 hasas its mission statement “…to assist themalnourished population of the world byenhancing the production of the oceans andfacilitating access to these fish by those most inneed”, by promoting technology to fertilize open-ocean waters using urea and otherammonia-based fertilizers. The University ofSydney’s Ocean Technology Group is alsopromoting ‘Ocean Nourishment’ technology as ameans of “increasing wild fish stocks andsequestering carbon dioxide from theatmosphere”4. A project associated with thisprogramme, in Kenya, proposes a large-scale‘Ocean Nourishment Plant’ on the Kenyan coastwhich will produce urea from natural gas sourcedfrom Saudi Arabia and use it to fertilize oceanwaters5. Urea fertilization of ocean waters doesnot yet appear to have been tested on anythingbut a very small scale, so the true impacts canonly be speculated on. The Subsistence FishingFoundation6, also associated with the University ofSydney, is also promoting this technology as away of improving larval fish nutrition and survival,which it is assumed will increase fishery yields (Luand Lu, 2009). There appears to be no realsubstantiation that any of these ocean fertilizationprojects are economically or technically feasible,let alone environmentally or socially acceptable.

III. OCEAN FERTILIZATION


Several private or quasi-private groups haveproposed large-scale experiments tofertilize the surface waters of large areas of

ocean in order to promote algal growth in nutrient-limited oceanic waters as a means ofsequestering carbon from the atmosphere. Thetheory is that small amounts of nitrogen,phosphorous or iron can be added to waterslacking these nutrients, and the subsequentgrowth and then sinking of algae will carry largeamounts of carbon into deep water and remove itfrom the atmospheric cycle. Modelling indicatesthat one atom of nitrogen, phosphorous and ironwould sequester 6,100 and 10,000 atoms ofcarbon respectively; hence most interest hasfocused on iron fertilization (using soluble ironcompounds, not iron filings). However, a recentreview of these ideas, most of which have notsucceeded in getting beyond the proposal stage,finds that: there are numerous untestedassumptions in regard to the actual fate of thecarbon removed from surface waters using thistechnology; and the complex trophic structurestypical of ocean food webs make the ecologicalimpacts and their consequences for nutrientcycling and flow hard to predict. Ocean fertilizationis considered likely to be feasible but not veryeffective; to have low long-term carbon storagepotential; to not be cost-effective; to requiresubstantial prior research for investigation ofenvironmental impacts, efficacy and verifiability;and to have high potential for unintended andundesirable ecological side effects, includingpossible creation of new anoxic regions of ocean(‘dead zones’) and slightly increased acidification

3 http://onf-ocean.org4 http://sydney.edu.au/science/usims/ocean_technology/research/nourish.shtml5 http://sydney.edu.au/science/usims/ocean_technology/research/kenya.shtml6 http://www.subsistencefishingfoundation.org


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Clark, M.R., D. Tittensor, A.D. Rogers, P. Brewin,T. Schlacher, A. Rowden, K. Stocks and M.Consalvey (2006) Seamounts, deep-sea coralsand fisheries: vulnerability of deep-sea corals tofishing on seamounts beyond areas of nationaljurisdiction. UNEP-WCMC, Cambridge, UK.

Clucas, I. (1997) A Study of the Options forUtilization of Bycatch and Discards from MarineCapture Fisheries. FAO Fisheries Circular C928,Rome, Italy.

Greer, D. and B. Harvey (2004) Blue Genes:Sharing and Conserving the World’s AquaticBiodiversity. Earthscan and the InternationalDevelopment Research Centre (IDRC), Ottawa,Canada.

Guinotte, J. (undated). Seamount Map of theIndian Ocean. Online document: www.savethehighseas.org/publicdocs/Indian-Ocean-map.pdf

ICES (2005) Report of the Ad-hoc Group on theImpacts of Sonar on Cetaceans and Fish.International Council for the Exploration of theSea, Copenhagen, Denmark.

Jacquet, J., D. Pauly, D. Ainley, S. Holt, P. Daytonand J. Jackson (2010) Seafood Stewardship inCrisis. Nature 467: 28-29.

Jasney, M., J. Reynolds, C. Horowitz and A.Wetzler (2005) Sounding the Depths II: The RisingToll of Sonar, Shipping and Industrial Noise onMarine Life. Natural Resources Defense Council,New York, NY, USA.

Kinchingman, A. and S. Lai (2004) Inferences ofPotential Seamount Locations from Mid-Resolution Bathymetric Data. In: Morato, T. and D.Pauly (Eds), Seamounts: Biodiversity andFisheries. Fisheries Centre Research Reports,Volume 12, Number 5. University of BritishColumbia, Canada.

Anderson, O.F. and M.R. Clark (2003) Analysis ofBycatch in the Fishery for Orange Roughy,Hoplostethus atlanticus, on the South TasmanRise. Marine and Freshwater Research 54(5):643-652.

Anon (2010) Underwater Acoustics SolveLongline Fishing Problem. Online document:http://www.bairdmaritime.com/index.php?option=com_content&view=article&id=7691:underwater-acoustics-solve-longline-fishing-problem&catid=75:fisheries&Itemid=68.

Baker, C., B. Bett, D. Billett, and A. Roger (2001)An Environmental Perspective. In: WWF/IUCN(Eds). The Status of Natural Resources on theHigh Seas. WWF/IUCN, Gland, Switzerland.

Boehlert, G. and R. Genin (1987) A review of theeffects of seamounts on biological processes. In:Keating, B. H, P. Fryer, R. Batiza and G. Boehlert(Eds), Seamounts, Islands and Atolls. Geophysicalmonograph #43, American Geophysical Union,Washington, DC, USA.

Borgatti, R. and E. H. Buck (2004) Open oceanaquaculture. CRS Report for Congress.Congressional Research Service, US Library ofCongress, Washington DC, USA.

Bridger, C.J. and B.A. Costa-Pierce (Eds) (2003)Open ocean aquaculture: from research tocommercial reality. World Aquaculture Society,Baton Rouge, Louisiana, USA.

Bridger, C.J. and T.H. Reid (Eds) (2001) OpenOcean Aquaculture IV, Symposium Program andAbstracts. June 17-20, 2001. St. Andrews, NB,Canada. Mississippi-Alabama Sea GrantConsortium, Ocean Springs, MS, USA.

Clark, M.R, S. O’Shea, D. Tracey and B. Glasby(1999) New Zealand Region Seamounts. Aspectsof their Biology, Ecology and Fisheries. Reportprepared for the Department of Conservation,Wellington.

IV. REFERENCES

www.savethehighseas.org/publicdocs/Indian-Ocean-map.pdf

Kite-Powell, H.L. (2008) Taking Finfish Aquacultureto the Open Ocean: US Experience andProspects. Marine Policy Center, Woods HoleOceanographic Institution, USA.

Koslow, J.A. and K. Gowlett-Holmes (1998) TheSeamount Fauna off Southern Tasmania: BenthicCommunities, their Conservation and Impacts ofTrawling. Report to the Environment AustraliaFisheries Research Development Corporation.95/058.

Lu, Q. and Y. Lu (2009) Harmful Algae Blooms.Volunteer Program Report, Urea Fertilizer Project,University of Sydney.

Mullineaux, L.S. and S.W. Mills (1997) A test ofthe larval retention hypothesis in seamount-generated flows. Deep-Sea Research 44:745-770.

Pitcher, T.J., M.R. Clark, T. Morato and R. Watson(2010) Seamount Fisheries – Do They Have aFuture? Oceanography, Vol. 23. No. 1.Oceanographic Society, Rockville, MD, USA.

Roberts, S. and M. Hirshfield (undated). DeepSea Corals: Out of sight but no longer out ofmind. Oceana, Washington DC, USA.

Rogers, A.D. (2004) The Biology, Ecology andVulnerability of Seamount Communities. IUCN,Gland, Switzerland.

Royal Society (2009) Geoengineering the Climate:Science, Governance and Uncertainty. RoyalSociety Policy document 10/09. The RoyalSociety, 6–9 Carlton House Terrace, LondonSW1Y, UK.

Smith, P. (2002) Managing biodiversity:Invertebrate By-Catch in Seamount Fisheries inthe New Zealand Exclusive Economic Zone.National Institute of Water and AtmosphericResearch, Wellington, New Zealand.

United Nations (2004) Oceans and the Law of theSea: Report of the Secretary General. UN GeneralAssembly, Fifty-ninth session, Item 50 (a) of theprovisional agenda. August 2004.

United Nations (2006) The Impacts of Fishing onVulnerable Marine Ecosystems: Actions taken byStates and regional fisheries managementorganizations and arrangements to give effect toparagraphs 66 to 69 of General Assemblyresolution 59/25 on sustainable fisheries,regarding the impacts of fishing on vulnerablemarine ecosystems: Report of the Secretary-General. UN General Assembly, Sixty-firstsession, Item 69 (b) of the preliminary list: Oceansand the Law of the Sea. July 2006.

Upton, H.F. and E.H. Buck (2010) Open oceanaquaculture. CRS Report for Congress.Congressional Research Service, US Library ofCongress, Washington DC., USA.

Wabnitz, C., M. Taylor, E. Green and T. Razak(2003) From Ocean to Aquarium: The GlobalTrade in Marine Ornamental Species. UNEP WorldConservation Monitoring Centre, Cambridge,United Kingdom.

Watson, R. and T. Morato (2004) ExploitationPatterns in Seamount Fisheries: A PreliminaryAnalysis. In: Morato, T. and D. Pauly (Eds),Seamounts: Biodiversity and Fisheries. FisheriesCentre Research Reports, Volume 12, Number 5.University of British Columbia, Canada.

Wilson, R. and R. Kaufman (1987) SeamountBiota and Biogeography. In Keating, B., P. Fryer,R. Batiza, and G. Backland (Eds), SeamountsIslands and Atolls. Geophysical Monographs 43.pp. 355-277, Washington.

REFERENCES



Shotton, R. (comp.) (2006) Management ofdemersal fisheries resources of the SouthernIndian Ocean. Report of the fourth and fifth AdHoc Meetings on Potential Management Initiativesof Deepwater Fisheries Operators in the SouthernIndian Ocean (Kameeldrift East, South Africa, 12-19 February 2006 and Albion, Petite Riviere,Mauritius, 26-28 April 2006) includingspecification of benthic protected areas and a2006 programme of fisheries research. FAOFisheries Circular no. 1020; FAO, Rome, Italy.

Keating, B.H, P. Fryer, R. Batiza and G. Boehlert(Eds) (1987) Seamounts, Islands and Atolls.Geophysical monograph #43, AmericanGeophysical Union, Washington DC, USA.

Morato, T. and D. Pauly (Eds) (2004) Seamounts:Biodiversity and Fisheries. Fisheries CentreResearch Reports, Volume 12, Number 5.University of British Columbia, Canada.Oceanography, Vol. 23, No. 1, March 2010.Special Issue: Mountains in the Sea.

Shotton, R. (Ed.) (2005) Deep Sea 2003:Conference on the Governance and Managementof Deep-sea Fisheries. (Part 1: Conferencereports / Part 2: Conference poster papers andworkshop papers). Queenstown, New Zealand,1–5 December 2003. FAO Fisheries Proceedings.No. 3/1. Rome, Italy.

V. OTHER USEFUL SOURCES


mm millimetre(s)Mn manganeseMARPOL International Convention for the

Prevention of Pollution from ShipsMSR Marine scientific research N2O nitrous oxideNi nickelNLS Noxious liquid substancesnm nautical milesNOx nitrogen oxidesOOA Open-ocean aquacultureOTEC Ocean thermal energy conversionP&I Protection and IndemnityPAHs Polycyclic aromatic hydrocarbonsPb leadPCBs Polychlorinated biphenylsPCDD Polychlorinated dibenzo-p-dioxinsPCDF Polychlorinated dibenzofuransPFCs PerfluorocarbonsPFOS Perfluorooctane sulfonic acidPFOS-F Perfluorooctane sulfonyl fluoridepH acidityPOPs Persistent organic pollutants Pt platinumROVs Remotely operated vehicles SF6 sulphur hexafluorideSIO Southern Indian OceanSIODFA Southern Indian Ocean Fishers’

AssociationSn tinSOx sulphur oxidesSSGFs Sub-seabed geological formationsSUA Convention Convention for the Suppression of

Unlawful Acts Against the Safety ofMaritime Navigation

TBT tributyltin UCH Convention Underwater Cultural Heritage

ConventionUN United NationsUNDP United Nations Development

ProgrammeUNEP United Nations Environment ProgrammeUNESCO-IOC United Nations Educational, Scientific

and Cultural Organization –Intergovernmental Oceanic Commission

VOCs Volatile organic compoundsWHO World Health OrganizationWMO World Meteorological OrganizationZn zinc

ABNJ Areas Beyond National JurisdictionAFS Anti-fouling systemsAg silverAs arsenicAu goldBCE Before Current EraBFRs Brominated flame retardants CBD Convention on Biological DiversityCCS Carbon capture and storageCd cadmiumCFCs ChlorofluorocarbonsCH4 methanecm centimetre(s)Cn cyanideCO carbon monoxideCO2 carbon dioxidedB decibelDDT dichlorodiphenyltrichloroethane DSL Deep-scattering layerESONET European Seafloor Observatory

Network FAO Food and Agriculture Organization (of

the United Nations)Fe ironGEF Global Environment FacilityGESAMP IMO/FAO/UNESCO-

IOC/WMO/WHO/IAEA/UN/UNEP JointGroup of Experts on the Scientific Aspects ofMarine Environmental Protection

GHG Greenhouse gas HABs Harmful algal bloomsHCFCs Hydro-chlorofluorocarbonsHFCs HydrofluorocarbonsHg mercuryHz hertzIAEA International Atomic Energy AgencyIAS Invasive alien species IBC International Bulk Chemical ICES International Council for Exploration of

the Sea IMO International Maritime OrganizationIUCN International Union for Conservation of

NaturekHz kilohertzkm kilometre(s)km2 square kilometresLBS Land-based sourcesLOSC UN Convention on the Law of the Sea m metre(s)

ABBREVIATIONS AND ACRONYMS

About IUCN

IUCN, International Union for Conservation of Nature, helps the world find pragmaticsolutions to our most pressing environment and development challenges.

IUCN works on biodiversity, climate change, energy, human livelihoods and greeningthe world economy by supporting scientific research, managing field projects all overthe world, and bringing governments, NGOs, the UN and companies together todevelop policy, laws and best practice.

IUCN is the world’s oldest and largest global environmental organization, with morethan 1,200 government and NGO members and almost 11,000 volunteer experts insome 160 countries. IUCN’s work is supported by over 1,000 staff in 45 offices andhundreds of partners in public, NGO and private sectors around the world.

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INTERNATIONAL UNION FOR CONSERVATION OF NATURE

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