Evaluating Artificial Means to Increase Acropora Coral Populations and Increase Associated Fish...

8/7/2019 Evaluating Artificial Means to Increase Acropora Coral Populations and Increase Associated Fish Communities in Jam

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ge 30 58th Gulf and Caribbean Fisheries Institute

INTRODUCTIONAcropora cervicornis was one of the most important

ef-building corals on Jamaican reefs three decades agooreau and Wells 1967). However, this species hasclined throughout the region, becoming locally extinctmany reefs (Knowlton el a/. 1990). The Caribbean wide

cline of Acropora corals in recent decades has seriousnsequences, affecting coral reef biodiversity, coastalology, and the fisheries and tourism economies of thegion. The seriousness of the decline is reflected in thecent proposed listing of A. cervicornis and A. pa/mara asreatened in the United States (50 CFR Parts 223 and4). This is a first for reef-building scleractinian coralsobally.

Several decades ago, the Acropora cervicornispulation at the West Fore reef at Discovery Bay wasduced to a mere 4% of its original cover by Hurricanelen (Woodley el af. 1981). Eight years later when

urricane Gilbert struck, the few recovering stands ofcropora that had survived Allen were smashed againWoodley 1981). Subsequent incidents of predation and

sease reduced the population to < 1% of its original levelnowlton et a/. 1981).

Rabimt complexity, defined by various measures ofnthic community structure, complexity and reef rugosity,a predictor of reef fish assemblage structure (Sale 2002).

he loss of acroporid communities in the Caribbean hassulted in loss of important fish habitat and changes in fishsemblages (Shulman and Ogden 1987). In the Indiancean, transplanted corals have been shown to enhanceh abundance and diversity (Linda! 2003).

Even on reefs where measures to address the rootuses of coral decline have been implemented, A.rvicornis populations do not appear to be recovering.

he causes are many, but one of the most important may beck of larval recruitment (Quinn and Kojis 2005a, 2005b,

press). There are a number of possible reasons for theck of larval-based recovery. Among them is that most ofe surviving A. cervicornis populations are too small toccessfully produce sufficient planula to re-colonize reefs

Kojis and Quinn 1985, 1993, 2001, Quinn and Kojis99).

Given the lack of observed recovery of A. cervicornis,

e sought to conduct experiments to determine which coralstoration techniques would be most effective in enhancg the recovery of dtis species. We also compared fishecies diversity and abundance on reefs with a highrcent cover of A. cervicornis and reefs with no A.rivcornis. It was hypothesized that reefs with a highrcent cover of A. cervicornis would have a greaterundance of larger edible fish species.

METHODS

Coral RestorationA large, healthy Acropora cervicornis population at

Dairy Bull Reef (18028.24 N; 770:24.08 W) at 9 m was used

asa source population for the restoration experiments. On

June 2, 2004, 160 fragments 5 - 14 em in length werecollected and transported in shaded buckets filled with seawater to the experimental sites. The transportation processtook < 4 hours.

A - Frame Experiment - Five Acropora cervicornisfragments were attached using cable ties to each outer sideof 14 wire mesh "A-frames" (0.8 rn x 1.2 m bent at 90)(Figure 1). A total of ten A. cervicornis fragments wereattached to each frame. The frames were tagged foridentification and weighted with dive weights or cementblocks to increase stability.

Figure 1. Coral fragments on cement disks on wire mesh(left) and on A-frames (right) in transit to experiment site.

The frames were deployed within Discovery Bay atColumbus Park Reef(18"46.448 N; 7741.428 W) - depth 6m; East Back Reef (1 S046.856 N; 77"40.454 W) - depth 4m; the Blue Hole (1847.252 N; 7741.662 W) - depth 2 m,Back Reef Canoe Channel (18"28.305 N; 77024.950 W) depth 2 m; and outside the bay at West Fore Reef(18"47.252 N; 77"41.662 W) - depth 6 rn.

Water quality and wave exposure varied among sites.At Columbus Park Reef, the water was turbid with avisibility frequently < 10 In. A. cervicornis had dominatedColumbus Park Reef for at least 6,000 years b.p., until itsdenilse a couple decades ago (Wapnick el 0/. 2004). TheEas1 Back Reef site was an area with clear water but wassubjected to breaking waves. The frames at Blue Holewere located in a back reef, lagoon environment withslightly turbid water. The Canoe Channel site was justbehind the reef crest at the West Fore Reef in clear oceanwater often was subjected to wave action. Black plasticnetting shade cloth was suspended over the frames forthree months at the shallow, clear Canoe Channel site toreduce sun intensity.


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Quinn, N.J. and B.L Kojis GCFI:58 (2007) Page 3

Fragments attached to the A-frames were monitoredfor survivorship and growth. Percent survivorship wascalculated by dividing the total number of live fragmentsby the total number of original fragments. A fragment wasconsidered live i f some living tissue remained. Missingfragments were counted as dead. Growth was measuredfrom the fragment base to the apical polyp of the dominatebranch an d then from the branching point to the apicalpolyp of each sub-branch. Th e lengths were addedtogether an d actual linear growth in length and percentagegrowth calculated

Cement Base Experiment - A 50150 cement/sand mixturewas p1"essed and dried into a 5 cm circular disk. A nylonmonofiJament line was placed through the disks to securethe small (5 - 7 em) coral fragments. The 211 disks weres ~ u r e d to a wire mesh sheet at the Canoe Channel (Figure

I) and were monitored for survivorship and growth.

Line Experiment - In June 2004, sixteen A. cervicornisfragments were collected and within - 4 hours the frag-ments were attached to monofilament nylon lines 1.5 mabove the substrate stnmg between iron rebars at the CanoeChannel. In September 2004, the experiment was repeatedwith 40 fragments. This time the fragments were deployed'Within 30 minutes of collection. Th e fragments weremonitored for growth and survivorship.

Fisb Census

The abundance and standard length (8L) of sevenfamilies of edible fishes (Groupers - F. Serrao.idae, Grunts- F. Haemulidae, Parrot fish - F. Scaridae, Snappers - F.LUUanidae, Squirrelfish - F. Holocentridae, Surgeon fish F. Acanthuridae, and Triggerfi.sh - F. Balistidae) wereswveyed on reefs with Acropora cervicornis % cover>40% and reefs depauperate of A. cervicornis ( - 0% coralcover). The stationary point-count method was used, inwhich fish families were identified and individuals largerthan lOcm were counted for 10 minutes within 10 mdiameter cylinders (polunin and Roberts 2004). Standardlengths of fish within each family were estimated andrecorded to the nearest two em. Te n observations weremade at on reefs with > 40 % A. cervicornis cover and onreefs with - 0% cover. A. cervicornis has a patchydistribution. Sites having reefs with high percentage coverof A. cen,jcornis an d also reefs devoid of A. cervicorniswere found at Dairy Bull (A. cervicornis coral cover - 900m 2) and East Rio Bueno (A. cervicornis coral cover - 1700

2m ).

RESULTS

Coral Restoration

A-frame Experiment - Corals were deployed on A-framfor 55 weeks at four sites. Columbus Park Reef hadhighest sllIVivorship - 78%. The lowest survivorshipat the two most exposed sites East Back Reef (7%) andCanoe Channel (4%). SurvivOTShip at Blu e Holes32%. Although Hurricane Ivan passed south of JamaicSeptember 2004, very large waves crashed over thecrest and severely damaged the experiment at CanoeChannel. The growth rate of corals on the framesmeasured 55 weeks after deployment. The mean lgrowth rate was 7.3 em (S.E. 7.0 em; n = 63), ranging fra mean of 1.1 em (S.E. 0.6 em; n = 16) at Canoe Chanto 15.3 em (S.E. 4.6 em; n = 40) at Columbus Park.

mean growth rate was 0.19 cmJweek - annualized meagrowth rate of9.7 cmJyear.

Cement Disk Experiment - During the first months tsurvival and growth of the colonies on the cement diskwas very good. Based on the first eight weeks of grothe annualized growth rate was 23 cmlyear. Colonquickly grew and established multiple branches with apolyps. However, after 37 weeks survivorship was on19%, and only 40 of the original 211 fragments were stialive. Many of the corals were killed or severely damaby wave action from Hurricane Ivan. After one year (June

2005) few complete colonies were alive. Several colonieshad live areas, but no apical polyps.

Line Experiment - T w o days after deployment in Ju2004, most coral fragments in this experiment bleacAll of the fragments were bleaching after five days andalgal growth on the branch skeletons was visibile. Nonthe colonies recovered A second deployment of fragmon lines occurred in September 2004. Five days later noneof the corals exhibited any bleaching despite watertemperatures being at their annual maximum (QuinnKojis 2003a). After 26 weeks, fragments from the secondattempt had a 32% swvival rate. The differencesurvivorship between June an d September is attributed the shorter length of time that colonies were heldcontainers prior to deployment in September compared'With June. In June 2005, the remaining colonies werdoing extremely well with an annualized percentagrowth rate exceeding 400%. Colonies were vigorouslygrowing from both ends an d have numerous branches wino sign of Hermodice canmculata predation or Stegabiles.


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Page 32 58th Gulf and Caribbean Fisheries Institute

Fish CensusFive of the seven familes of fish (groupers (F.

Serranidae), grunts (F. Haemulidae), snappers (F. Luljanidae), squirrelfish (F Holocentridae) and surgeon fish (F.Acanthuridae had a greater abundance on the Acroporareefs (AR) than on the non Acropora reef (NAR). (Figure2). The mean number of edible fish observed on theAcropora reefs (AR) varied from 3.3 fish per observationperiod for triggerfish (F. Balistidae) to 73.2 fish perobservation period for grunts. Parrot fish - F. Scaridaewere significantly more abundant on NAR (t-test, p < 0.05;n = 20). Groupers were not significantly (t-test, p > 0.05; n= 20) more abundant on NAR by 1.9 fish per obserservation. Parrot fish were more abundant on NAR, but thedifference was not significant. Surgeon fish were notsignificantly more abundant on AR (t-test, p < 0.05; n =20). There was no significant difference observed (t-test, p> 0.05; n = 20) in the standard lengths of fish between ARand NAR (Figure 3).

DISCUSSIONThe results suggest that the success of restoration is

very site specific. Local variations in abiotic conditionslike wave exposure, salinity, depth, and turbidity influencesurvival and growth rates. As well, biotic influences suchas abundance of fire worms and damselfish can influrencegrowth and survival. Frames on sand did considerablybetter than frames on rock or rubble. Frames on sand wereaway from lurking places of predatory Coraliophila snails

and Hermodice fire worms, as well as Stegastes damselfish(Family Pomacentridae) territories. Weighing the framesdown with cement blocks at some sites resulted in theinadvertent creation of ideal Stegastes habitat, withsubsequent negative impacts to the corals. The size of thewire mesh also affected growth and survival. Small meshframes provided ideal shelter for damselfish and permittedmore surface area for the fanning algae. In January andMarch 2005, new wire frames with larger apertures (20 x20 cm) were placed on sand at least I m from a reef. Thesize of the mesh reduced algal fanning by Stegastes and thedistance from the reef inhibited predation while still beingclose enough to the reef for herbivorous fish to visit the

frames regularly for cleaning.

Management ImplicationsArguments Acropora cervicornis restoration to reefs

that are expirated are compelling for many reasons. A.cervicornis is a keystone species of critical importance tobiodiversity, fisheries, and tourism interests. It is particularly vital as fisheries habitat due to it being the only largeopen-branched coral species of reef slope, back reef, andlagoonal environments. Its loss represents a loss to thebiodiversity and essential fish habitat of Caribbean reefs.

Acroporid Reefs 0 Non Acroporid Reefs

90 - - - - - -80

70

.s::IJ)

u..'Ito

c:

60

50

40

"") 30:;;

20

10

o +-------'-r--

Figure 2. Mean number of edible fishes from selectedfamilies on acroporid reefs vs non acroporid reefs.

Acroporid Reefs 0 Non Acroporid Reefs

- _....5130E

~ f- -:. 25 rt F!

I

C,c:., 20 ~ "'"E 15 Iff--co

"0c: =tlo 10Vi

5

- -

Figure 3. Standard length of edible fish from selectedfamilies on acroporid vs non acroporid reefs.

rt T- ~ 1 n- - -- - -

' - -


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QUinn, N.J. and B.L. Kojis GCFI:58 (2007) Page 33

The Acropora reefs had a greater abundance o fschooling species. Parrot fish were slightly more commonon NAR possibly because their food was more abundantthere. Another possibility is that they are avoiding spaceoccupied by other species. There were slight differencesbetween standard lengths between the two reef types, butthe difference was not significant. Considering the intensefishing pressure in the area and the relatively small area o fhealthy reef, it is probable that fishing pressure is too hightoo observe any statistically significant difference.

A. cervicornis is not retwning to reefs where it wasformerly common (Wapnick et al. 2004), as sexualrecruitment o f Acropora is rare or absent in the Caribbean(Sammarco 1985; Quinn and Kojis 2005a). Given the lowlevels of sexual recruitment o f A. cervicornis, its long-termsurvival is threatened and a proactive approach may beneeded to restore healthy populations. A. cervicornis

provides habitat for many edible fish, serving as a vitalnighttime resting place and providing shelter frompredation during the day. Reefs with with higher percentage Acropora cover have more edible fish.

However, restoring healthy, breeding populations o fstaghorn coral inexpensively, even in limited areas, is notlikely to succeed until the factors that caused the population collapse are better understood and mitigated. Currentobservations suggest that the long-term survival of A.cervicornis is threatened unless root causes o f decline aremore effectively addressed throughout the region, andsuccessful sexual reproduction occurs. There are manyfactors that are considered to have influenced the rapid

reduction in populations. Runoff from land contributes toalgal overgrowth by increasing nutrients in the watercolumn and contributes to outbreaks o f coral disease(Bruckner et al. 1997). Increased sediment is known toreduce coral fecundity (Kojis and Quinn 1984) and maydiminish the success o f settlement o f coral larvae (Quinnand Kojis 2005a). In the Caribbean, chronic over fishing isan ever increasing threat to coral reefs (Hughes 1994).Overfishing combined with the decline in the grazing seaurchin, Diadema antillarum (McClanahan 1994), hasresulted in algal overgrowth (Szmant 1997) and reducedspace for new coral to settle (Jackson 1997). The declinehas also been linked to the lack o f predators, especially fishpredators, resulting in increases in corallivorous gastropods(McClanahan 1997) and in Acropora harming Stegastesfish (Lewis 1986).

Due to the high costs o f restoration, we need innovative, efficient techniques to guide us in restoring damagedhabitats. We a r e working to determine what techniqueswork best to restore Acropora cervicornis on select reefssites. Restoration may not be necessary in some situationsif the populations can naturally recover (Kojis and Quinn1981) as they do on some Pacific Reefs (Quinn and Kojis1999,2003b).

The experimental strategy is to increase habitat andcoral diversity by successfully transplantating A. cervicornis branches from populations where it is abundant tohabitats where it once thrived but is no longer found.Surviving A. cervicornis populations may be resistantwhite band disease and tolerant o f higher sea watertemperatures, some of the causes o f the decline of thisspecies. The population would still be prone to predationand hurricane damage and vulnerable to declines in waterquality. With the implementation o f measures to addressthe root causes o f coral reef decline, including the establishment o f no-take marine reserves in several Caribbeancountries, transplanted patches o f A. cervicornis maysurvive and flourish. Once the fish, crustaceans, echinoderms and other species that positively influence coralhealth become more abundant, coral populations couldimprove without further assistance.

ACKNOWLEDGEMENTS

We are grateful for the fmancial assistance provided byUSAID through the CWIP2 program and for the use o f thefacilities o f the Discovery Bay Marine Laboratory,University o f the West Indies. Additional financial supportwas provided by Counterpart International, TropicalDiscoveries Fund, and the National Institutes o f Healththrough the University o f Mississippi under the terms o fagreement No. R21 TW006645 funded by the FogartyInternational Center and the National Institute for ResearchResources for the International Cooperative BiodiversityGroups. The opinions expressed herein are those o f the

authors and do not necessarily reflect the viewso f

theNational Institutes of Health or the University of Mississippi. A Bowden-Kerby and M Stennett deserve particularrecognition for their assistance in the initial phase o f thecoral restoration experiment. This is DBML publication#722.

LITERA TURE CITED

Bruckner, A. W., RJ . Bruckner, and E.H. Williams Jr.1997. Spread of black-band disease epizootic throughthe coral reef system in St. Ann's Bay, Jamaica.Bulletin o f Marine Science 61:919-928.

Goreau, T.F. and l W . Wells. 1967. The shallow-waterScleractinia of Jamaica: revised list o f species andtheir vertical distribution range. Bulletin o f MarineScience 17:442-453.

Hughes, T.P. 1994. Catastrophes, phase shifts and largescale degradation o f a Caribbean coral reef. Science265:1547-1551.

Jackson, J.B.C. 1997. Reefs since Columbus. Proceedingso f the 8'h International Coral Reef Congress. 97-106pp.


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is, B.L. and N.J. Quinn. 1981. Factors to consider intransporting coral to accelerate regeneration ofdamaged coral reefs. Pages 183-1871in: Proceedingsof the Environmental Engineering Conference, 1981.8-10 July, Townsville, Queensland Institute ofEngineers Publication 8/81.

is, B.L. and N.J. Quinn. 1984. Seasonal and depthvariation in fecundity of Acropora palifera at tworeefs in Papua Ne w Guinea. Coral Reefs 3:165-172.

is, B.L. and N .l Quinn. 1985. Puberty in Goniastreafavulus: age or size limited? Proceedings o f the 8 th

International Coral Reef Symposium 4:289-293.is, B.L. and N.J. Quinn. 1993. Biological limits to

Caribbean reef recovery. Pages 35-41 in: A compari-son with western South Pacific reefs. Global Aspectso f Coral Reefs, Health, Hazards, and History. Miami,Florida USA

is, B.L. and N.J. Quinn. 2001. The importance ofregional differences in hard coral recruitment rates fordetermining the need for coral restoration. Bulletin ofMarine Science 69(2):967-974.

owlton, N., J.C. Lang, M.C. Rooney, and P. Clifford.1981. Evidence for delayed mortality in hurricanedamaged Jamaican staghorn corals. Nature 294:251252.

owlton, N., lC . Lang, and B.D. Keller. 1990. Casestudy of natural population collapse: Post hurricanepredation of Jamaican staghorn corals. Smithson.Contributions in Marine Science 31:1-25.

wis, S.M. 1986. The role of herbivorous fishes in theorganization of a Caribbean reef community. Ecologi-cal Monographs 56:183-200.

dahl, U. 2003. Coral reef rehabilitation through

transplantation of staghorn corals: effects of artificialstabilization and mechanical damages. Coral Reefs22:217-223.

Clanahan, T.R. 1994. Kenyan coral ree f lagoon fish:effects of fishing, substrate complexity and seaurchins. Coral Reefs 13:231-241.

Clanahan, ToR. 1997. Dynamics of Drupella comuspopulations on Kenyan coral reefs. Proceedings o f the8

thInternational Coral Reef Symposium 1:633-638.

unin, N.V.C. and C.M. Roberts. 2004. Greater biomassand value of target coral-reef fishes in two smallCaribbean marine reserves. Marine Ecology Progress

Series 100:167-176inn, N .l and B.L. Kojis. 1999. Case studies of natural

variability in coral recruitment from the Caribbean andPacific. Which reefs need restoration assistance? Page159. in: Proceedings o f the International Conferenceon Scientific Aspects o f Coral Reef Assessment,Monitoring and Restoration, Ft. Lauderdale, FloridaUSA.

Quinn, N .l and B.L. Kojis. 2003a. Variation in subsurfaceseawater temperature of f Discovery Bay, Jamaica andthe U.S. Virgin Islands. Revista de Biologia Tropical51(4):181-187.

Quinn, N.J. and B.L. Kojis. 2003b. The dynamics of coralreef community structure and recruitment patternsaround Rota, Saipan, and Tinian, Western Pacific.Bulletin o f Marine Science 53:646-661.

Quinn N .l and B.L. Kojis. 2005a. Patterns of sexualrecruitment of acroporid coral populations on the WestFore Reef at Discovery Bay, Jamaica. Revista deBiologia Tropical 53(1):83-90.

Quinn, N .l and B.L. Kojis. [2005b]. Natural variability inthe recovery of reef ecosystems. In: W.F. Precht (ed.).Coral Restoration. CRC Publications, Boca Raton,Florida USA In press.

Quinn, N .l and B.L Kojis. [In press]. Evaluating thepotential of natural reproduction and artificial meansto increase Acropora cervicornis (Lamark, 1816)populations. Revista de Biologia Tropical.

Sale, P. 2002. The science needed for effective manage

ment. Pages 359-376 in: P. Sale (ed.). Coral ReefFishes: Dymanics and Diversity in a ComplexEcosystyem. Academic Press, San Diego, CaliforniaUSA

Sammarco, P.W. 1985. The Great Barrier Reef vs. theCaribbean: comparisons of grazers, coral recruitment

5thpatterns and reef recovery. Proceedings of the

International Coral Reef Congress 4:391-397.Shulman, M .l and lC . Ogden. 1987. What controls reef

fish populations: recruitment or benthic mortality? Anexample in the Caribbean reef fish Haemulon fla-volineatum. Marine Ecology Progress Series 39:233

242.Szmant, AM. 1997. Nutr ient effects on coral reefs: A

hypothesis on the importance of topographic andtrophic complexity to reef nutrient dynamics. Proceed-ings o f the 8 th International Coral Reef Symposium2:1527-1532.

Wapnick, C., W.F. Precht, and R.B. Aronson. 2004.Millennial-scale dynamics of staghorn coral inDiscovery Bay, Jamaica. Ecology Letters 7:3564-361.

Woodley, lD. , E.A. Chornesky, P.A. Clifford, lB.C.Pearson, J.W. Porter, M.C. Rooney, K.W. Rylaarsdam,V .l Tunnic1iffe, C.M. Wahle, J.L. Wulff, AS.C.

Curtis, M.D. Dallmeyer, B.P. Jupp, M.AR. Koehle, lNiegel, and E.M. Sides. 1981. Hurricane Allen 'sImpact on Jamaican Coral Reefs. Science 241(4522):749-755.

Woodley, J.D. 1981. The effects of Hurricane Gilbert onCoral reefs At Discovery Bay. Appendix 9 in: UNEPRegional Seas Reports an d Studies, No. 110.

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