From the Editor Bill Jones · issue should be an educator’s dream with the extremely strong group...

12 Summer 2011 / LAKELINE

From the Editor Bill Jones

( . . . continued on page 40)

Lake ecology is a subject very near and dear to my heart . . . and to the hearts of most NALMS members.

From catching tadpoles (we called them polliwogs) in the neighborhood “marsh” and keeping them alive in tubs of water only to marvel at their transformation into frogs, to watching

herons stand silently on guard waiting to snare their next meal, or to catching minnows in a makeshift net – all these were early lessons in aquatic ecology observed during my youth. Little did I know that these early lessons would lead to a lifetime of educating college students and the public about aquatic ecology. Lake ecology is a fundamental piece of the lake management puzzle. Through the study of lake ecology, we can understand how the physical, chemical, and biological parts interact to yield the lake conditions we see and measure. In other words, do these parts fit together into a sustainable lake ecosystem? If they don’t, then we can examine the individual parts more closely to investigate what is wrong or out of balance. In this issue of LakeLine we focus on lake ecology, particularly the biota. This issue should be an educator’s dream with the extremely strong group of authors assembled. NALMS stalwart Ann St. Amand leads off with a thorough and extremely well-illustrated article about lake phytoplankton. With 29 superb images of algae, her article will help most of us amateur phycologists with our identifications. Ann, for many years, has

In MemoriamJody N. Connor, a NALMS member since 1986, died Thursday, June 9, 2011, at Concord (NH) Hospital after a long illness.

Jody completed his undergraduate studies at Boston College and St. Joseph College in Windham, Maine, and then received his master’s degree from the Florida Institute of Technology. Jody took a special interest in a number of areas of limnology, including paleolimnology, algal ecology, cyanobacteria toxins, stormwater runoff, and exotic species, among others.

Jody worked for the state of New Hampshire, Department of Environmental Services (DES), for 32 years, the last 20 of which he served as the Director

of the DES Limnology Center. Dedicated to his science, he was instrumental in establishing several freshwater programs, including the Volunteer Lake Assessment Program, Beach Inspection Program, Clean Lakes Program, Exotic Species Program and Public Bathing Facility Program. Jody was a NALMS Regional Director (Region 1) from 1993 to 1995. Always a passionate advocate for lake education – and especially for programs that reached out to youth – he chaired NALMS’ Education Committee from the late 1990s to the present, and co-authored Interactive Lake Ecology, a limnology-based curriculum for middle school students that has been used across the country and sold in the NALMS Bookstore. Additionally, Jody was an active member of the NALMS Student Awards Committee. Jody’s mission was to educate and empower others to protect and enhance lakes and their watersheds in New Hampshire and beyond. His enthusiasm was simply contagious; in his quiet, unassuming way he inspired all those around him to care more and to work harder for quality lakes. Family, friends, colleagues, and countless lake lovers and stewards are bereft at his loss.

taught the algal identification workshop at annual NALMS symposia with Ken Wagner. No stranger to NALMS workshops, John Beaver has taught several zooplankton identification workshops at NALMS symposia. John, Teodoro Rosati, and Kyle Scotese share their knowledge of zooplankton and their ecology in this equally well-illustrated article.

I’ve found that students of all ages really get into aquatic macroinvertebrates. They are fun to collect and interesting to observe. David Mitchell writes about these fascinating and diverse organisms and their important role in aquatic food webs. Moving up the lake food chain we come to fish, the lake inhabitant most


familiar to people. Don Kretchmer describes the functional role of fish in lakes and how fish can actually be used to manage lakes. Finally, as an avid bird watcher, I wanted to include aquatic birds in this issue. So, we conclude our lake ecology theme with an article by Michael Schummer on the role of waterfowl in lake food webs. It is especially interesting to read how waterfowl are new allies in the battle against zebra mussels. In the “Student Corner,” Chelsey Campbell proves that student research doesn’t have to be boring to solve one of life’s puzzling questions. In the “Worldviews,” Frede Anderson, Sara Egemose, and Henning Jensen of the Center for Lake Restoration in Denmark, write about lake management issues in that country. Also in this issue, we hear about summer activities from our Affiliates in Florida, Indiana, and New York. Summer is almost here and there are many exciting events on the horizon, including Lakes Appreciation Month in July, the NALMS Photo Contest, annual NALMS elections and awards, and the annual NALMS Symposium, this year in Spokane, Washington. You’ll learn details about all of these in this LakeLine. We complete this issue as always with “Literature Search.” Finally, on a personal note, I’d like to announce my early retirement from Indiana University, effective June 30. After more than 33 years at IU, I’d like to have more time for other interests. We don’t plan to leave Bloomington but do plan to travel more and spend more time with the grandkids. I will continue as LakeLine editor and look forward to having even more time to devote to NALMS.

(FROM THE EDITOR. . . continued from page 10)

Summer 2011 / LAKELINE 13

Bill JonesFrom the President Bev Clark

The theme for this issue is Lake Ecology. The best definition of this that I could find is: The study

of the relationships among aquatic living organisms and between those organisms and their environment. One simple example? If you manage a lake’s phosphorus

concentrations to minimise algal blooms, then you are an aquatic ecologist. When I reflect on what I’ve been doing all these years it occurs to me that I have spent a ton of time measuring the individual pieces that interlock to represent aquatic ecosystems. I have spent countless hours putting water in bottles, conducting zooplankton hauls, mapping plants, capturing fish (and crayfish), scraping periphyton off rocks, and pulling sediment cores out of lakes. Each of these efforts produced data that told me something about the algal biomass, or the nutrient status, or the diversity of the zooplankton population, or the abundance of crayfish relative to the previous year or to some other site on the other side of the lake. That’s the simple stuff. Brave ecologists go forward to describe the relationships between multiple living organisms and their environment(s) – and that is where it gets really tricky. If you are lucky, you can manage to get two of the components to regress favourably with one another. More often than not it doesn’t work because there is some third party messing things up. So then you employ multiple regressions or ordinations to

try to describe the interdependencies between the different creatures and their environment. Sometimes you have bad data and it doesn’t work. Sometimes you have good data and it still doesn’t work – because there is a further external driver that has more effect on the thing that you are trying to measure than everything else put together. Climate change comes to mind. This is why lake managers get together at conferences. They need to cry on each other’s shoulders about how things just aren’t going so well with their data. I jest, of course. They get together to compare notes, to support each other’s programs, and to share information that is relevant to their co-workers. Then they hatch plans to improve their own initiatives or to collaborate to solve common problems. I often tell people that I have learned everything I know about lake management at NALMS conferences. So, this would seem like the point where I should go off to plug NALMS conferences – not yet. I just came back from a Lake Simcoe Protection Plan workshop (a bit like a conference) where researchers from all over Ontario (and further afield) convened to describe the current state of understanding relative to issues in the Lake Simcoe watershed. Near to the end, Dr. Evans presented data that showed convincing evidence that there are (and has been for many years) trophic cascades across many levels in the lake. These have pushed and pulled predator and planktivorous fish populations, zooplankton and phytoplankton communities, and water clarity back and forth in response to species invasions,

stocking programs, etc., etc. This was shown to occur through many cycles over many years and indicated an ecosystem that was, at any given time, operating at some accumulated state that had recently changed and was well on its way to some other state. Demonstrating this required the data that had been collected over many years by dedicated people who froze in the dark tagging fish or who hauled zooplankton nets on the stormy seas in the centre of Lake Simcoe. Managers in the room could clearly see how their own little smidgen of data might fit within this twisted, ecological dance routine. It made you feel a bit like you were studying a piece of a puzzle rather than lording over a hopeless dataset. But what if you missed this talk . . . ? What if you didn’t know . . . ? Okay, now I can segue to the NALMS conferences. I would say go to them! You might be missing something important.

Bev Clark worked for 35 years with the Ontario Ministry of the Environment conducting whole lake experiments at the Dorset Environmental Science Center. He now works as an aquatic scientist with Hutchinson Environmental Sciences in Bracebridge, Ontario. x

LakeLine encourages letters to the editor. Do you have a lake-related question? Or, have you read something in LakeLine that stimulates your interest? We’d love to hear from you via e-mail, telephone, or postal letter.


How Algae Fit into Lake Food Webs Ann St. Amand

Lake Ecology

Welcome to the wild and wacky world of algal population dynamics! Many of you may

remember the term, WYSIWYG, coined in the ’80s as word processors became more sophisticated and companies started advertising that what you actually saw on the computer screen was what you were going to get when you printed. Programming that series of commands to make the text print in bold, indented, and capitalized is somewhat like the many processes that determine what algal species or communities will dominate under different environmental scenarios. We often observe what would appear to be similar lakes with totally different dominant communities and our inclination is to figure out why, so we can predict what might bloom in the next few weeks or months (Figure 1). Unless you

understand the system functionally, you can’t effectively manage it. Not only is the entire aquatic food web based on the algal composition at any given time (okay, and maybe the bacteria, too), but the ultimate community affects how much carbon enters the lake system, the trophic status, how much stress the system is under from too much or too little algal biomass, the perceived water quality (which in turn affects property values), and ultimately how safe the water is for human and animal contact. The question becomes: What population dynamics are responsible for the taxa that are present? Amazingly, it’s all about the relatively simple proportions of growing versus dying. Many algal taxa have evolved very ingenious survival strategies to tip the scales toward growing. There are some great references on general

algal ecology available and just a few of my favorites are listed at the end of this article.

Growth Processes . . . Or What Grows Up . . . So let’s start with the growth part of the equation. It all initiates with primary productivity, the process of adding carbon via photosynthesis. In order to photosynthesize, you have to have pigment. The pigment common to all of the different algal groups is chlorophyll-a (as a reminder, algae are an evolutionary trash can, so the only thing they have in common is that they photosynthesize). Chlorophyll-a does not absorb green, instead it reflects green, so that’s exactly what the most common algal color is, just like land plants (Figure 2). Epi-fluorescence is a special enhancement on a microscope that allows us to shine a specific wavelength of light on the algae (excitation), and

WYSIWYG (What you see is the result of a whole bunch of different processes going on at the same time!)

Figure 1. (Left): Green algae dominated bloom (Cladophora); (right): Blue-green algae dominated bloom (Microcystis).


Figure 2. Examples of green algae. (Left): Ulothrix; (right): Pediastrum.

it shines back a different wavelength of light (emission). A taxon like Chara or stonewort has a lot of pigment, which is really obvious when you put it under blue light epi-fluorescence (Figure 3). No matter what the pigment (there are also accessory pigments called carotinoids, and phycobilins in addition to other chlorophylls), primary productivity potential will be modified by light and nutrient availability, temperature (sometimes many weeks prior to a bloom), algal physiology, and competition. Some algae do well under low light, low temperature conditions such as Plantothrix (Figure 4), forming pink blooms under the cracked ice or at depth during the summer and fall. Others have developed specialized structures called

heterocysts to fix nitrogen when it’s in short supply in the water column such as Cylindrospermopsis (Figure 5). But beating the nutrient and temperature game is only part of the equation. Algae must maintain their position in the water column so that they can be at optimum light, be near the nutrients they need, and hopefully avoid grazers (more about that below). There are some amazing adaptations for staying where they need to be. Some algae have solved the problem with motility, like Pyramichlamys and Cryptomonas (Figure 6). Others have developed buoyancy mechanisms by either adding oils to their colonial structure (Botryococcocus, Figure 7) or air vesicles to their cells or filaments like Microcystis (Figure 8). Yet others

have spines or extensions that increase their surface area and slow their sinking (Stephanodiscus and Micratinium, Figure 9). Staying near the light for photosynthesis may be a problem in winter, at depth or under intense competition, so many algae have evolved additional routes for nutrition. On the spectrum of nutrition, there are pure autotrophs where algae can only photosynthesize, and then the facultative heterotrophs, which can augment with or completely switch to heterotrophy (clever little cells!). Heterotrophy can take the form of osmotrophy (uptake of organic compounds in the water) and phagotrophy (ingestion of organic material or even bacteria and other algae). Diatoms exhibit classic osmotrophy (Nitzschia, Figure

Figure 5. Cylindrospermopsi with terminal heterocysts.

Figure 4. Planktothrix from an under ice bloom.Figure 3. Chara (stonewort). Chlorophyll-a fluoresces red while the calcium carbonate glows green on the filament surface.


Figure 6. Examples of motile algae. (Left): Pyramychlamys; (right): Cryptomonas. Figure 7. Botryococcus with oil droplets.

Figure 8. Microcystis with clear air vesicles (arrows).

Figure 9. Examples of cell extensions. (Left): Stephanodiscus; (right): Micractinium.

Figure 10. Nitzschia, capable of absorbing organic compounds.

Figure 11. Facultative heterotroph – Euglena.

10). There are also algae, like many euglenoids (Euglena, Figure 11), which has members who either uptake compounds or phagasotize. Then there are those that supplement nutrition only through phagotrophy (Cryptomonas and Dinobryon, Figure 12). In fact, Dinobryon cannot be cultured without bacteria present! That brings us to the coolest strategy of all: dinoflagellates. These ingenious algae, like Ceratium (Figure 13), exude something called a “pallium” that engulfs other algal colonies. The algal cell then swims around with the pallium attached, digesting the algae inside, and when they’re done sucking up the nutrients, the pallium is jettisoned and the dinoflagellate goes in search of another algal colony to digest. Continuing on our quest to add cells or biomass to the water column


Figure 12. Facultative heterotrophs. (Left): Cryptomona; (right): Dinobryon. Figure 13. Ceratium.

is recruitment from the sediments. This one is tricky only because it’s both a loss and growth process depending on where you hit the cycle. There are really only two options at the end of the growing season: Either a small inoculum remains up in the water column so that next season the growth cycle can start again, or cysts or resting stages are produced that settle down to the bottom and wait for either the right conditions or turbulence to bring them up again. Many different groups of algae take advantage of cyst or resting cell formation. Chrysophytes, like Dinobryon, and dinoflagellates like Ceratium (Figure 14), produce cysts that float down to the bottom and wait for the right environmental conditions (increasing light and nutrients, and increased turbulence at turnover) to bring them back up into the water column to begin the life cycle again. Others, like many members of the blue-green algae, produce either condensed filaments of a few cells called hormogonia (Plectonema, Figure 15) or resting cells called akinetes (Aphanizomenon and Anabaena, Figure 16). Akinetes in particular are extremely robust and can sit in the sediments for decades (or even centuries!), waiting for a turnover event to bring them back up into the light. Additionally, akinetes often sit on the sediment surface, waiting for the proper increases in light and temperature, and then start growing on the bottom without needing turbulence to re-suspend them. After a certain amount of growth, the colonies start to produce gas vesicles (remember buoyancy described above) and they rise on their own up through the

Figure 14. Cyst forming algae. (Left): Dinobryon; (right): Ceratium.

water column. Many of these blue-greens are good at luxury uptake of phosphorus as well, so that by the time they get to the surface, nutrient availability is not an issue and they can continue blooming with relatively low surface nutrient concentrations. That brings us to the non-growing part of the conversation, but still a process that adds cells to the water column, and that is colonization. Although many of us have to deal with invasive species regularly, let’s ignore the human-induced sources here like ballast water. That leaves the few natural ways that algal cells can be moved from system to system. Although floods and drift from upstream are key mechanisms, and actually well documented, don’t forget the seemingly less obvious sources either. Aerialization is one mechanism that is

Figure 15. Plectonema hormogonia.

often under-quantified. We know that algal toxins and cells in lake spray and updraft from lakes during wind and storm events can be measureable. The other often overlooked and under-appreciated


Figure 16. Examples of blue-green akinetes. (Left): Aphanizomenon; (right): Anabaena. Figure 17. Migratory waterfowl.

Figure 18. Asterionella infected with a parasite.

Figure 19. Examples of remnants of dead cells. (Left): Dinobryon; (right): Pediastrum.

source is movement by wildlife, and more specifically, waterfowl. We honestly can’t overlook the ubiquitous “duck feet and feathers” as a common source of recruitment to new systems (Figure 17).

Loss Processes . . .Or What Must Eventually Senesce . . . Loss processes are equally important and are often operating simultaneously with the growth processes (kind of like photosynthesis and metabolism). The most obvious is physiological mortality. All cells have to die sometime, and whether they are single cells or colonial, often an entire population will senesce within a week or two. Although limiting resources or the inability to stay up in the water column during stratification are often the driving force behind physiological death, infections and parasites like chitrids are also important.

This is very common in Asterionella and other colonial diatoms (Figure 18). When naked flagellates (cells with no particularly hardy outer cell wall or casing) like Cryptomonas or Chlamydomonas die, they are very labile in the water column and often leave no lasting evidence. Other algae with more robust cell walls or tests (cases that enclose the cell made of silica or cellulose) often leave empty cells around as evidence for several days to weeks (Dinobryon and Pediastrum, Figure 19). As discussed above, many of these algae will produce cysts (Peridinium and Cosmarium, Figure 20) or akinetes before the end of the season as light, nutrients and temperature become limiting (see above). Other loss processes that need to be considered include sedimentation and/or burial. Strategies to survive include cyst

or resting cell formation (see above), or in an added twist, the ability to migrate back to the surface. This includes several motile genera of diatoms. Remember too, that physiological health greatly affects sinking rates, so the healthier the cell or colony is, the less likely it is to sink. Hydraulic washout can be a factor, especially in reservoirs or during a flood (not much the algae can do about that one!). Desiccation can happen during normal hydrologic cycles or following large geologic events. The blue-green algae handle desiccation the best, often growing well after being dried for long time periods. Grazing is perhaps the most complicated loss process because although it often results in death, sometimes it results in growth if you happen to be one of the lucky ones that benefits from grazing, directly or


Figure 20. Examples of encysting algae. (Left): Peridinium; (right): Cosmarium. Figure 21. Cyclopoid Copepod.

indirectly. Top down control (grazing) is always competing with bottom up control (resource availability like light and nutrients). If algae avoid being grazed, it’s very possible that they may benefit when competitors are grazed. Grazer size is one of the main determinants in how much grazing pressure the algal community experiences. Copepods (Figure 21) can be predatory (cyclopoids) or herbivorous (calanoids), but as a group are selective and not very large (less than 1 mm for the most part, with a small threshold on food items). Rotifers are much smaller (grazers generally less than 0.3 mm), but they can exert consistent grazing pressure on smaller algae, especially single cells flagellates like Pyramichlamys (Figure 22). This brings us to the workhorses of the grazer world, cladocerans. The smaller cladocerans like Bosmina are too

small to be very effective grazers (0.4-0.5 mm, Figure 23), so although they eat their fair share, they can only do so much damage to the algal community. Daphnia (0.5-3.5 mm), however, are considered to be generalist grazers (pretty much anything that can pass through the feeding apparatus or up to about 30 µm, Figure 24). Any Daphnia above 1 mm is considered to be an effective grazer (kind of like teenage boys). Interestingly, although very large colonies such as the Aphanizomenon above and large Anabaena colonies (Figure 25) are out of bounds, Daphnia have good success grazing the periphery of Gloeotrichia colonies (Figure 26). They actually make good use of picoplankton when present as well (Figure 27). Cryptomonas avoids grazing by migrating down in the water column at night, away from the grazing Daphnia. Micractinium spines keep it up

in the water column, but they also make it hard to eat. It’s unclear whether the algal toxins produced by blue-green algae are a defense mechanism against grazing or secondary metabolites, but when they are producing toxins in high concentrations, there tend to be fewer zooplankton in the water column. Food preference goes as follows:

Cryptomonads > Diatoms/Chrysophytes > Greens > Blue-greens

Indirect effects within the grazer world can be significant as well. Sphaerocystis is one of the algae (gulp) that can successfully travel the zooplankton gut, absorbing nutrients along the way (Figure 28). Other algae benefit from differential grazing. Microcystis (Figure 29), for example, is not a preferred food of zebra/quagga

Figure 22. Brachionus (rotifer) grazing on Pyramichlamys.

Figure 23. Bosmina (Cladoceran). Figure 24. Daphnia (Cladoceran).


mussels, but benefits from the release from competition that occurs when these mussels filter everything else out of the water column and then excrete in a nutrient ratio favorable to Microcystis. So the next time you are passing by an interesting lake, before you ask yourself how best to manage it, perhaps you should ask yourself who’s physiologically healthy and who is eating whom?

ReferencesAmerican Water Works Association

(AWWA). 2010. Algae – Source to Treatment – Manual of Water Supply Practices, M57 (1st Edition). Denver, CO. 439 pp.

Graham, L.E. and Wilcox, L.W. 2000. Algae. Prentice-Hall, Englewood Cliffs, NJ., USA. 640 pp.

Reynolds, C.S. 1984. The Ecology of Freshwater Phytoplankton. Cambridge University Press. New York NY. 384 pp.

Sandgren, C.D. 1988. Growth and Reproductive Strategies of Freshwater Phytoplankton. Cambridge University Press. New York, NY. 442 pp.

Sommer, U. 1989. Plankton Ecology: Succession in Plankton Communities. Springer-Verlag. New York, NY. 369 pp.

Wehr, J.D. and Sheath, R.G. 2003. Freshwater Algae of North America. Academic Press, Boston. 918 pages.

Ann St. Amand, Ph.D., has been involved in managing lakes across the United States since 1990, as President of PhycoTech, which specializes in aquatic sample analysis, with an emphasis on algae and zooplankton. St. Amand has processed over

29,000 algal samples in her career and has co-chaired a workshop on Algal Identification at the annual NALMS symposium since 1991. She also serves on several technical and educational committees at the local and national level, including the Indiana Blue-Green Algal Task Force and the Plankton Sections of Standard Methods for the Examination of Water and Wastewater. In 2003, she became a NALMS Certified Lake Professional. St. Amand has been a member of NALMS since 1987 and has served NALMS in many positions. x

Figure 25. Anabaena colony. Figure 26. Gloeotrichia colony that has been grazed by Daphnia.

Figure 27. Moina with picoplankton (the bright red rods and spheres are picoplankton in the 1-2 µm range) in the gut.

Figure 28. Moina with Sphaerocystis (green algae) in the gut.

Figure 29. (Left): Dreissena before settling; (right): Microcystis colony.


Lake Ecology

Got Daphnia? Why it Matters to Lake ManagersJohn R. Beaver, Teodoro C. Rosati & Kyle C. Scotese

A description of the zooplankton community of a lake or reservoir can provide managers with

considerable information about the characteristics of the fish population and algal composition. Because of their pivotal position in the planktonic food web, they are critical to packaging photosynthetic energy into biomass. Zooplankton are animals suspended in the water column with limited powers of locomotion and include protozoa, rotifers, and two subclasses of microcrustaceans – cladocerans and copepods. The smallest zooplankton (microzooplankton), protozoa and rotifers, are generally less than 0.2 mm (microbial food web, see Havens and Beaver 2010). The larger zooplankton (macrozooplankton) include copepods and cladocerans (the subject of this paper) differentiated on the basis of body structure, length of antennae, and legs. Most cladoceran zooplankton in North American lakes and reservoirs are small (0.2 to 3.0 mm), possess a distinct head, and the body is covered by a bivalve carapace (Figure 1). Locomotion is accomplished mainly by means of the large second antennae. The cladoceran Daphnia (water flea, named after the Greek virgin nymph, Daphne, who also thrived without males) is distributed globally and is the keystone zooplankton species in both lakes and reservoirs. Filter-feeding Daphnia are often the principal grazers of algae as well as the other components of the microbial food web. Daphnia are the primary food for many larval and forage fish and thus higher trophic levels. The intermediary position of cladocerans should be of special interest to lake managers because they are essential to efficient energy transfer from phytoplankton to higher

trophic levels. Robust populations of large cladocerans such as Daphnia are associated with clear lakes supporting healthy sport fish populations. They are widely utilized as an indicator species to assess the response of ecosystems to environmental change because of their well-described genome and genetic plasticity.

Cladoceran Zooplankton Feeding/Distribution Most non-predatory cladocerans use suspension-feeding of particles (i.e., algae, bacteria, detritus) to collect food. The effectiveness of this grazing varies seasonally and among lakes and reservoirs. Generally, the potential filtering rates of cladoceran zooplankters are proportional to body size and increased temperatures (Table 1). All types of phytoplankton are grazed, but cyanobacteria are the least preferred, as they are capable of producing toxins that may reduce the fitness of cladocerans. Cladoceran feeding rates usually stabilize or decrease as concentrations of food particles increase. Herbivorous zooplankton communities only filter a small portion of the water column each day, but if the algal food quality is high they can graze enough particles to cause marked increases in water clarity and alter algal species composition. Assimilation efficiency is variable, but is usually less than 50 percent, and even less efficient when the plankton is dominated by detritus. A positive correlation usually exists between the rates of production of phytoplankton and of zooplankton in an individual lake or reservoir. The structure and composition of temperate zooplankton communities are significantly altered with high trophic state and is accompanied by less efficient

energy transfer to higher trophic levels. Although the total abundance of all zooplankton groups increases with increasing trophic state, simultaneously there is a shift in dominance from large-bodied cladocerans such as Daphnia (more efficient, high per capita filtering rates, Figure 1) to small-bodied cladocerans such as Bosmina, Chydorus, and Ceriodaphnia (less efficient, lower per capita filtering rates, Figure 2). A greater proportion of the phytoplankton biomass in oligotrophic and mesotrophic lakes and reservoirs is composed of smaller, more edible and nutritious algae while higher productivity systems have larger (colonial or filamentous), less edible and less nutritious forms of phytoplankton such as cyanobacteria. Larger particles reduce food collection efficiency by increasing the time needed to manipulate the food. This can result in reduced growth and fecundity disproportionately for large-bodied cladocerans. Increased cyanobacterial populations associated with warmer temperatures would be an additional pressure for Daphnia. In addition, the larger cyanobacteria may clog the feeding apparatus of large-bodied zooplankton such as Daphnia and toxic strains negatively affect early survival and population growth (Sarnelle et al. 2010).

Predation by Fish and Size Selectivity Planktivorous fish are often important in regulating the composition, abundance, and size structure of cladoceran zooplankton populations. Vertebrate planktivores (e.g., bass, bluegill, perch, threadfin shad) visually locate their prey based on size or may collect cladoceran zooplankton less discriminately on gill rakers by pump-filter feeding (e.g., gizzard shad). Similarly, invertebrate


Figure 1. Photomicrographs of representative Daphnia from lakes or reservoirs of varying latitudes displaying a positive correlation of latitude and Daphnia body length: (a) Daphnia magna from Shaker Lake, OH photographed at 35X, (b) Daphnia middendorffiana from British Columbia, Canada photographed at 35X, (c) Daphnia pulex from Lake Mead, NV photographed at 35X, (d) Daphnia catawba from Branch Lake, VT photographed at 40X, (e) Daphnia ambigua from Lake Okeechobee, FL photographed at 100X. (f) Photomicrograph of the invasive species Daphnia lumholtzi from Lake Okeechobee, FL photographed at 50X. Photographed by Teodoro Rosati, Thomas Renicker, Kyle Scotese, and John Beaver.

a b c

d e f

predators (e.g., predaceous cladocerans and copepods, phantom midge larvae) use size-selective predation on smaller zooplankton including Daphnia. Organism size and swimming patterns are major factors in prey selection by planktivorous fish. Cladocerans are

the most vulnerable zooplankton to predation because of their slower and steady swimming movements. Because zooplankton communities are structured by both top-down (fish predation) and bottom-up (food quality and quantity) trophic interactions, they are valuable

for characterizing lakes and reservoirs. Brooks and Dodson (1965) in their seminal publication described the size efficiency hypothesis that states that large-bodied cladocerans are better competitors for food than small-bodied species, however, large-bodied cladocerans will


Table 1. Body Size and Filtering Rates of Common Cladocerans in North American Lakes and Reservoirs.

Species Size (mm) Filtering Rate (ml animal-1 day-1) Daphnia magna 2.5-3.0 76.8Daphnia pulex 1.3-2.9 20.4-26.9Daphnia galeata 1.5-1.7 3.7-6.4Daphnia parvula 0.7-1.2 3.8Ceriodaphnia quadrangula 0.7-0.9 4.6Bosmina longirostris 0.4-0.6 0.44Chydorus sphaericus 0.1-0.2 0.18

Modified from Wetzel 2001 and McCullough and Reat 1991.

suffer higher predation losses than small-bodied species due to size-selective predation by planktivorous fish. When top-down factors in a plankton food web are strong, the cladoceran community is likely to be reduced in overall numbers and body size.

Vertical and Horizontal Migration Survival for cladoceran zooplankton in the water column often necessitates avoiding predation by daily vertical and/or horizontal migrations. Some zooplankton, particularly cladocerans, exhibit marked diurnal vertical migrations as refugia from predation by size-selective fish predators.

The migration patterns typically follow an upward movement from deeper strata to higher in the water column during darkness when sight-feeding fish are not active and the subsequent return to deeper areas at dawn. Some cladocerans are known to migrate up and down 20 meters or more nightly, the equivalent of a human running a nightly marathon. Rates of grazing are often greater during dark conditions. Vertical migration in deeper lakes may also provide cooler, thermal refugia during summer months allowing modest populations to persist when water temperatures are not optimal. The bottom range of vertical migration is often defined

by decreased oxygen concentrations in the hypolimnion. Vertical migration may also reduce competition among filter-feeding zooplankton taxa, allowing multiple species to use food resources located in different levels of the water column. The spatial distribution of zooplankton is notoriously uneven and patchy within a lake or reservoir, and water currents, avoidance of light, Langmuir circulations, and planktivorous fish avoidance have all been implicated.

Cyclomorphosis and Predation Cyclomorphosis (seasonal polymorphism) is an adaptive feature that many species of cladocerans use to reduce predation and includes significant elongation in some dimension of the organism (Figure 3). Enlargement of the peripheral features decreases capture success of both invertebrate and vertebrate predators. Cyclomorphosis by cladocerans is well described and has been shown in temperate systems to be induced by increased temperature, turbulence, photoperiod, and food availability. Typically in the spring with increasing water temperatures in North American lakes and reservoirs, there is an extension of the head to form a helmet and/or elongation of the tail spine (Figure

Figure 2. Photomicrographs of representative small-bodied cladocerans from North American lakes and reservoirs: (a) Eubosmina tubicen from Branch Lake, VT photographed at 100X, (b) Chydorus sphaericus from Orman Lake, WY photographed at 200X, (c) Ceriodaphnia spp. from Shaker Lake, OH photographed at 100X. Photographed by Teodoro Rosati, Thomas Renicker, Kyle Scotese, and John Beaver.

a b c


Figure 3. Photomicrographs of representative Daphnia displaying helmet cyclomorphosis: (a) Daphnia retrocurva from Cheney Reservoir, KS photographed at 50X, (b) Daphnia retrocurva from Orman Lake, WY photographed at 40X, (c-d) Daphnia galeata from Lake Mead, NV photographed at 100X. Photographed by Teodoro Rosati, Thomas Renicker, Kyle Scotese, and John Beaver.

a b

c d

3). Cyclomorphosis is less common with decreasing latitude. Enlargement of peripheral features has an energetic cost to the organism since the energy used to produce the additional appendage is no longer available for reproduction but is essential for survival during periods of high predation (Figure 1f).

Latitude and Temperature A well-described seasonality for Daphnia in the temperate zone includes rapid increase in the spring, declines in summer, followed by increase again in fall. Temperature is important for Daphnia growth and reproduction. Peak populations have been shown to occur at

approximately 18ºC and to decline rapidly at water temperatures greater than 20ºC, indicating that regardless of latitude, water column temperatures and individual thermal regimes of particular lakes and reservoirs are the important determinants for Daphnia seasonality. There is a decline in the mean size of cladocerans in the temperate zone with decreasing latitude such that the average size of cladocerans is considerably smaller in subtropical areas such as Florida (Figure 1a-e). Although physiological constraints (higher water column temperatures) in lower latitude lakes have been suggested as a major factor (Gillooly and Dodson 2000), more intense fish predation and an increased proportion of small planktivorous fish in warmer lakes and reservoirs are likely the key factor in the absence or very modest populations of large-bodied cladocerans (Iglesias et al. 2011).

Climate Change Potential impacts of climate change on plankton trophic interactions may include disruption (decoupling) of established food web relationships. Daphnia life history traits include a strong relationship between body-size, fecundity and feeding efficiency, with optimal temperatures approximately at 18ºC (winter, fall in temperate systems) and decreasing population and metabolic status at lower and higher temperatures. Acceleration of the timing of elevated temperatures in the spring may alter thermal regimes and the timing of peak high quality food (e.g., cryptomonads, diatoms) in lakes and reservoirs. Because of Daphnia’s reliance on appropriate thermal conditions for population expansion in the spring, their seasonal success may be reduced if their principle food is not synchronized with their populations. The timing, extent, and taxonomic composition of phytoplankton spring blooms are often synchronized with Daphnia community dynamics. Winder and Schindler (2004) demonstrated the unique and differing responses of Daphnia and diatoms to the timing of a warmer spring water column in Lake Washington, where thermal stratification and the spring diatom bloom were accelerated while Daphnia population peaks were delayed and reduced. Potential impacts of climate change on planktonic cladoceran


communities would be expected to result in an increased importance of small-bodied forms such as Bosmina, Chydorus, and Ceriodaphnia which are more tolerant of elevated temperatures but less efficient in transferring energy to higher trophic levels, resulting in less desirable fish populations (Figure 2).

Conclusions Planktonic crustaceans, particularly cladocerans, are highly sensitive to local and changing environmental conditions. The composition of the cladoceran zooplankton communities of North American lakes and reservoirs has clear implications for the perceived desirable uses of these resources. Robust populations of Daphnia suggest a more balanced aquatic ecosystem in the traditional sense. Eutrophication, whether natural or manmade, typically produces a less desirable zooplankton community from a food web or managerial standpoint. Additional, multiple stressors such as climate change and associated alterations to individual lake and reservoir thermal regimes and/or anthropogenic impacts to watersheds suggest that large-bodied zooplankton communities in North American lakes and reservoirs will be less common in the future.

ReferencesBrooks, J.L. and S.I. Dodson. 1965.

Predation, body size, and the composition of plankton. Science 150:28-35.

Gillooly, J.F. and S.I. Dodson. 2000. Latitudinal patterns in the size distribution and seasonal dynamics of new world, freshwater cladocerans. Limnol. Oceanogr. 45:22-30.

Havens, K. and J. Beaver. 2010. Microbial food webs and lake management. LakeLine 30(2):32-35.

Iglesias, C., N. Mazzeo, M. Meerhoff, G. Lacerot, J.M. Clemente, F. Scasso, C. Kruk, G. Goyenola, J.Garcia-Alonso, S.L. Amsinck, J.C. Paggi, S. Jose de Paggi and E. Jeppesen. 2011. High predation is of key importance for dominance of small-bodied zooplankton in warm shallow lakes: evidence from lakes, fish exclosures and surface sediments. Hydrobiologia 667:133-147.

McCullough, J.D. and V.L. Reat. 1991. Effects of temperature and body length

on filtering rates of two chydorid cladocera. The Southwestern Naturalist 36:237-242.

Sarnelle, O., S. Gustafsson and L. Hansson. 2010. Effects of cyanobacteria on fitness components of the herbivore Daphnia. J. Plankton Research 32:471-477.

Winder, W. and D.E. Schindler. 2004. Climate change uncouples trophic interactions in an aquatic ecosystem. Ecology 85:2100-2106.

Wetzel, R.G. 2001. Limnology: Lake and River Ecosystems. San Diego: Academic Press.

John Beaver, Ph.D., is president of BSA Environmental Services in Beachwood, Ohio (e-mail: [email protected]). He is an aquatic ecologist specializing in North American lake water quality and has authored more than 40 referred journal articles related to aquatic

microbiology and limnology in the scientific literature.

Ted Rosati is a senior environmental scientist at BSA Environmental Services in Beachwood, Ohio (e-mail: [email protected]). He specializes in freshwater and marine zooplankton taxonomy and ecology in North America water bodies. He has over 12 years of research experience in zooplankton ecology, phycology and aquatic ecology.

Kyle Scotese is a senior algal taxonomist at BSA Environmental Services in Beachwood, Ohio (e-mail: [email protected]). He has researched algae, specifically diatoms, and their relationship to water quality in North American lakes and reservoirs for eight years. x


The Complexity of Aquatic Food WebsDavid F. Mitchell, CLM

Lake Ecology

Lakes and ponds are mosaics of natural habitats occupied by aquatic plants and animals. Like other

realms of nature, the forces of life and death are constantly at work within these habitats. An aquatic plant leaf is grazed down by an insect that, in turn, is taken by a minnow, which ends up as lunch for a passing pickerel. These links, which control or modify patterns of energy production and transformation, are often conceptually portrayed as diagrammatic food web relationships (Figure 1). These food webs are typically portrayed as pyramids, mimicking the relative reductions in biomass between each ascending food chain step or trophic level, as higher organisms need to consume large numbers of prey to sustain growth and reproduction. In reality, aquatic food web relationships tend to be much more extensive and complex, as many organisms are both omnivorous and opportunistic, feeding on whatever the environment offers that day, be it plant, animal, or detritus (the polite term for dead and rotting organic material).

Why are Food Webs of Interest? For ecologists, these food webs are convenient conceptual tools to summarize the principal means by which energy (in the form of carbon) and nutrients are exchanged, altered, or exported in the aquatic ecosystem. The exact form and components of food webs can differ with lake type, geographic region, and season, and comparative limnology often finds insight in these differences. Looking at the propagation and interaction of direct and indirect population effects up and down the food chain, a process that is

Aquatic Food Webs – The Intricate Gears of a Functioning Ecosystem

Figure 1. Typical aquatic food web. Source: USEPA 2009. Users Guide and Technical Documentation. KABAM. Version 1.0 (Kow (based) Aquatic BioAccumulation Model). Environmental Fate and Effects Division; Office of Pesticide Programs. Electronically accessible at: http://www.epa.gov/oppefed1/models/water/kabam/kabam_user_guide.html#Section1_3.

termed “trophic cascades,” provides lake managers with interesting biological options for ecosystem restoration (Carpenter et al. 1985). For anglers, food webs supply useful advice for selecting the best fly or lure to tempt a crafty

bass out of the weed beds. For the local lakeside resident, knowledge of food webs provides greater appreciation of the natural drama occurring just offshore and better understanding of the importance of maintaining local shoreline habitats.

PHYTOPLANKTON

MAMMALS WATERFOWL

LARGE FISH

MEDIUM FISH

FORAGE FISH

ZOOPLANKTON

BENTHOS FILTER FEEDERS

WATER COLUMN

SEDIMENTS


While aquatic food webs are often portrayed in cartoons as a succession of bigger and bigger fish madly snapping each other up, reality is much more mundane. The aquatic food web that is the most studied is that found in open waters, which includes four trophic levels: phytoplankton (primary producer), zooplankton (primary consumer), young-of-the-year or forage fish (secondary consumer), large piscivores, such as lake trout or eagle (tertiary consumer). In shallow waters, analogous trophic levels may include rooted aquatic plants (macrophytes), snails, crayfish, and smallmouth bass. Research tracking food sources via isotopic markers has indicated that in many lakes the benthic food chains may be more important to fish diets than the open water (Vander Zanden and Vadeboncouer 2002).

Ecological Zonation Within a Lake In understanding lake food webs, it is important to recognize that most of the action is located relatively near the shoreline, in the shallow, well-lit waters that are termed the littoral zone (Figure 2). The role of this structured edge habitat is critical to lake-wide energy and nutrient dynamics. The littoral zone is more physically complex than the homogeneous limnetic zone that constitutes the main open waters of a lake. Continuing outward and downward from the shore, the waters get colder and darker in the profundal zone, which is beyond the reach of light and which receives a steady rain of detritus from the productive upper waters. Found near, upon, or within the bottom substrates of the littoral and profundal zones in lakes and ponds is a community of aquatic invertebrate life forms that are collectively known as the benthos. The benthos is comprised of a diverse collection of creatures, including many familiar creatures such as dragonflies, mayflies, mosquitoes, midges, backswimmers, snails, crayfish, freshwater mussels, and leeches – benthic aquatic macroinvertebrates inhabiting numerous substrates including rocks, sand, sediment, woody debris, and aquatic vegetation. Aquatic macroinvertebrates are important as the trophic or feeding links between the energy and nutrients released through the consumption of algae, plant material, and decomposition

Figure 2. Zonation of lake habitat. Source: Pearson Education, Inc.

of organic material and the nutrition of higher organisms. As the mid-level connection in the aquatic food web, macroinvertebrates are often the principal prey for juvenile and adult stages of fishes, but may also be utilized by reptiles, amphibians, waterfowl (ducks, shorebirds) and wildlife (muskrat, otter). Since describing the vast array of aquatic macroinvertebrates and their food web roles would be a challenge for a textbook, we offer instead a glimpse of some representative macroinvertebrates found in distinctive habitats on or within the lake and which have unusually important role in structuring the aquatic community.

Life at the Top and Within the Weeds At the very top, we encounter insects that are specialized for life at the air-water interface, which use the surface tension of the water as a stable platform for support as well as a source of sustenance. The surface is the playground of the gyrinids or whirligig beetles that can occur in aggregations of thousands (Figure 3). Whirligig beetles earned their common name from the adult’s wildly sporadic swimming behavior. While their rapid circular movement may attract inquisitive fish, they secrete distasteful chemicals that deter predators from feeding on them. Whirligig beetles have other interesting adaptations for “life at the top.” For example, they possess a specialized organ at the base of the antennae that enables them to echolocate

using surface wave vibrations. In addition, their compound eyes are split into two pairs, one for watching above and one below the water surface, enabling them to detect both aerial and aquatic predators. Gyrinds scour the surface film of the water, feeding on the small animals and materials displaced from terrestrial habitats by wind or runoff, forming an important energy transfer between the earthly and watery worlds. Going deeper into the littoral zone, beds of macrophytes are common lair for damselfly nymphs. Damselflies are close taxonomic cousins to the swifter, larger dragonfly, but their larval or nymph form can be distinguished by their delicate narrow body form with three gills extending in a tripod formation at the posterior end. Their brown and green coloration provides a measure of camouflage, allowing the nymph to blend within the habitat of plants and pond bottoms (Figure 4). Damselfly nymphs are voracious predators and feed on snails, other insects, crustaceans, worms, and even small fish. They are classic ambush predators, lying in wait for prey to get within range and then explosively shooting their extensible jaw out to grab and reel back their victim, in a mode that served as the model for the Alien movie predator’s deadly attacks.

Life in the Bottom and Deeper Still Leaving the weeds beds, we may happen upon a sandy or gravelly patch


of bottom, especially along well-washed pond margins, where populations of freshwater mussels can be found. Like their better known saltwater brethren, these filter-feeding freshwater “clams” spend most of their lives partially buried, pulling water into their bodies, filtering it to remove food particles, and pumping the rest back into the environment. Mussels play a pivotal role in aquatic ecosystems, consuming large portion of phytoplankton and zooplankton, and, in turn, providing food for many fish and mammals species. Freshwater mussels often comprise the largest proportion of benthic biomass (i.e., weight) since they can sequester significant amounts of minerals and

Figure 3. Adult gyrinds (whirligig beetles). Credit: Bobbi Peckarsky.

Figure 4. Damselfly nymph. Credit: Lars Hedin.

nutrients in their shells. As described below, when large numbers of mussels are present, they can significantly shift the balance of energy flow from the open water to the nearshore environment. In shallow, productive lakes with soft, organically rich bottom sediments, burrowing mayflies may be found in profusion (Figure 5). Burrowing mayflies are a favored food of bottom-eating fish such as yellow perch, freshwater drum, and various catfish species. Where abundant, the flying swarms of hatching adults can cause temporary nuisances for local residents due to their prolific numbers (and messy remains) mobbing backyard porch lights, splattering auto

windshields, and piling up in windrows on local beaches. Since burrowing mayflies are very susceptible to low oxygen and/or sediment contamination, they are useful ecological indicators of good water quality or ecosystem recovery. Venturing into deeper northern lakes, we may encounter opossum shrimp (mysids), a so-called “relict” species whose present geographical distribution reflects the extent of ancient glacial ice advances. These crustaceans are relatively small, omnivorous, and are a major food source for fishes (Figure 6). To avoid fish predation, mysids seek refuge in deep, unlit waters during daytime, feeding on benthic prey and detritus in the sediments. As dusk approaches, they rise upwards in long vertical migrations (e.g., >300 ft) to feed on zooplankton and algae in the mid-waters, returning to the protective bottom waters at dawn. Due to this lifestyle, this species forms an important link in the transfer of energy between the benthic and pelagic food webs. Their role in the food web is further complicated because mysids can affect the size, structure, and abundance of zooplankton, which has secondary impacts on zooplankton-eating fish, with potential effects up the trophic levels to top wildlife predators such as bears and eagles. In the depths of the profundal zone, we encounter a cold, dark habitat with little or no plant cover and sparse physical structure. These fine, silty sediments are home to chironomid or midge larvae. Midge larvae are small, wormlike creatures that are ubiquitously distributed throughout aquatic ecosystems, even in highly polluted or oxygen-poor waters. Larvae of some midge species have bright red coloration due to the abundance of hemoglobin in their bodies earning the nickname of “bloodworms.” Chironomids feed on algae, bacteria and organic matter in the water and sediment. In most lakes, midge larvae constitute the most numerically abundant aquatic insects and are a steady source of food for many bottom-feeding fish.

Critical Linkages of Energy and Nutrients While these are but a few of the species within a food web, what links all these species to each other is the transfer of energy, nutrients, and unfortunately, pollutants. Energy transfers are typically


Figure 5. Burrowing mayfly nymphs. Credit: Bobbi Peckarsky.

Figure 6. Mysid shrimp. Credit: unknown.

measured by ecologists by the amount of organic carbon that flows between trophic levels. Each successively higher trophic level requires more energy and biomass to sustain its population. While this might suggest that all potential prey must go the way of tooth and claw, the fact is most of the organic biomass is not directly consumed by predators. The majority of aquatic plants and animals simply peacefully expire and their decaying remains become the feast for bacteria, fungi, and detritivores (those animals and fish that specialize in the recycling business). Some of this material is rapidly recycled to the water column, while a

large amount is buried in the bottom sediments. Food webs are very important in recycling nutrients, nitrogen, and phosphorus between waters, sediments and the tissues of living organisms. Zooplankton grazing on phytoplankton leads to significant release of nutrients during the summer. When other phytoplankton pass through these enriched patches of water, they readily take up these nutrients, which sponsor new growth and biomass. Similarly, as bits of decaying macrophyte hit the bottom, scavenging insects and bacteria can recycle nutrients to the water column. Nutrients in the sediment can be released by the activities of burrowing mayflies that can re-suspend previously buried nutrients into the water column, increasing local productivity. Alternatively, nutrients can be exported from a lake system when a mink makes a meal of a crayfish or insect larvae hatch and take wing.

What Food Webs Tell Us About Lakes Gone Bad Scientists can also use food webs diagnostically to identify types of stresses (e.g., eutrophication, toxics, invasive species, etc.) that are altering expected patterns of community organization since imbalances in the expected numbers or diversity of a trophic level may be a clue to causal factors. The over-fertilization of

lakes from nutrients (also called cultural eutrophication) leads to overabundance of phytoplankton, shading out and reducing rooted plant growth and leading to a shift in resources away from benthic areas. Our knowledge of food webs has also been enhanced by the study of trophic transfers of bioaccumulative chemicals (e.g., DDT, mercury, PCBs) that trace the increase in concentrations of body burdens of these chemicals up the food chain, often with disastrous results for the top predators. This process is also the reason for the posting of fish advisories for lakes in many regions of the country. Invasive species can alter the patterns of energy flow in food webs. For example, lakes colonized by non-native nuisance, macrophyte species (e.g., Eurasian watermilfoil, fanwort) may increase numbers of macroinvertebrate species sheltering in the stems and leaves that reduce access to fish predators. Perhaps the most dramatic example of trophic alteration in our lifetime has been the invasion of the Great Lakes drainage system by the non-native zebra mussel (Figure 7). Due to its rapid colonization and prolific numbers, the cumulative high filtration capacity of zebra mussel beds has profoundly altered the aquatic food web in afflicted lakes. Since zebra mussels became established in Lake Erie, the combined filtration of these invasives has purged the water of so much phytoplankton that water clarity has increased from 6 inches to 30 feet in some areas (USGS 2008). Reduction of the phytoplankton that supply food for larval fish and other invertebrates has resulted in the reduction of populations of some pelagic fish species. On the other hand, benthic-feeding fish species (yellow perch, freshwater drum, catfish, and lake sturgeon) have adapted to feed on the zebra mussels. It has been reported that some species of migratory ducks have changed their annual flight patterns in response to the locations of zebra mussel colonies.

Using Food Webs to Help Make Lakes Right Again Our increased awareness of food web interactions has found practical application in lake management. For lake managers, altering patterns of predation pressure by, for example, stocking large numbers of a predator gamefish is a well-


Figure 7. Zebra mussel colonies. Credit: David Strayer.

recognized lake management technique called biomanipulation. Briefly, for this “top-down” biomanipulation example, a rise in large piscivore biomass brings decreased numbers of planktivorous fish, increases biomass of grazing zooplankton, and decreased phytoplankton biomass, to meet the objective improving lake conditions (e.g., increased clarity). Biomanipulation has proved successful in some lakes and less so in others, suggesting that factors such as depth or nutrient supply can confound the success of the technique (Benndorf et al. 2002). While most shoreline residents rarely get to practice lake management on the large scale, there is a portion of the lake where they hold sole domain and can positively influence local aquatic food webs. The recent comprehensive lake survey, the National Lake Assessment (NLA), was conducted in 1,048 lakes over the nation (USEPA 2010). In the NLA survey, lakeshore habitat was rated poor in 36 percent of the lakes. Poor ecological community health was three times more likely in lakes with poor lakeshore habitat relative to lakes with good habitat. These findings reinforce the need for today’s shoreline residents to (1) retain native bordering vegetation, (2) conserve valuable littoral zone habitat such as submerged logs and branches at the water’s edge, and (3) not disturb existing bottom substrates submerged aquatic vegetation (i.e., do not import sand to

make a beach). These lake stewardship actions will link you to maintaining the integrity and biodiversity of the interacting species found just off your shore.

ReferencesBenndorf, J., W. Boing, J. Koop and I.

Neubauer. 2002. Top-down control of phytoplankton: the role of time scale, lake depth and trophic state. Freshwater Biology 47:2282-2295.

Carpenter, S.R., J.F. Kitchell and J.R. Hodgson. 1985. Cascading trophic

Interactions and lake productivity. BioScience 35:634-639.

United States Environmental Protection Agency (USEPA). 2010. National Lakes Assessment: A Collaborative Survey of the Nation’s Lakes. EPA 841-R-09-001. U.S. Environmental Protection Agency, Office of Water and Office of Research and Development, Washington, D.C. April 2010.v

United States Geological Survey (USGS). 2008. Invasive Species Program. Invasive Invertebrates: Zebra Mussel. Great Lakes Research Center. Ann Arbor, MI. Electronically accessible at: http://www.glsc.usgs.gov/main.php?content=research_invasive_zebramussel&title=Invasive%20Invertebrates0&menu=research_invasive_invertebrates

Vander Zanden, M.J. and Y. Vadeboncouer. 2002. Fishes as integrators of benthic and pelagic food webs in lakes. Ecology 83:2152-2161.

Dr. David F. Mitchell is a senior associate at Abt Associates, Inc. of Cambridge, MA, with over 25 years experience in aquatic resource assessment and management, and is a member of the inaugural (1991) class of NALMS Certified Lakes Managers. x


The Role of Fish in Lake ManagementDon Kretchmer, CLM

Lake Ecology

Do Fish Matter?

Are fish an important component of lakes? The quick answer is that it depends on your perspective, if you

are an angler the answer is an unqualified yes. If you are a lake visitor or resident who doesn’t fish, the answer might be no. If you are a lake manager, the answer might have been maybe historically but these days most lake managers would say that the answer is yes. Traditionally, fisheries managers looked at lakes as a place to store an inventory of fish, the goal being to keep the inventory steady through natural reproduction or stocking as anglers take fish out or to create new “products” for anglers by introducing new fish species that anglers might like to catch (Figure 1). Limnologists and lake managers often looked at lakes from another perspective, as mixing bowls of water and nutrients, where what goes in must balance what accumulates plus what goes out. Out of this soup grew some algae and aquatic plants and maybe a few zooplankton or bugs. Fish had water quality requirements for temperature and oxygen but were of little consequence in terms of their influence on lakes. Over the past several decades, the fisheries and water quality folks have gotten together to figure out how water quality might influence fish and how fish might influence water quality. This led to some interesting research suggesting that the nature of the lake dictates the type and number of fish present and the type and number of fish present can dictate the nature of the lake. In other words, we now know that fish are a critical part of the living system of lakes.

Figure 1: A stringer of piscivores from the past. Today many more anglers release large fish which helps keep fish populations in balance.

Types and Roles of Fish in Lakes Despite the experiences of some anglers, nearly all lakes have some fish. There are a few exceptions but they are rare and are special cases that warrant their own article. Fish in lakes can be divided into a few general groups that roughly match up with where they live, where they feed, what they eat, and ultimately, what their role is in the lake ecosystem. Benthivores dine predominantly on insects and insect larvae in the sediments, on sediment directly, or on plants rooted to the sediment. Bullhead, sucker, and carp are all examples of benthivorous fish.

Herbivorous fish, such as grass carp, eat aquatic plants. Planktivores feed primarily on free swimming zooplankton in the water column. Often these fish are found in the middle of the water column (pelagic) and are not associated with the bottom or shallow water near the shore. Examples of planktivores include alewife, threadfin and gizzard shad, and golden shiner (Figure 2). Piscivores are the top predators. They feed on other fish including planktivores, benthivores and young piscivores. Examples include bass, pike, walleye, and musky (Figure 3). Many piscivores will even eat their young if the opportunity arises. In some work I


Figure 2: The golden shiner, a common planktivore in many lakes and ponds. Note the small mouth that is adapted for eating small prey.

Figure 3: Smallmouth bass are a critical piscivore in many northern lakes.

did in graduate school in Peter and Paul Lakes on the upper peninsula of Michigan it was common to find young-of-the-year largemouth bass in the stomachs of juvenile bass and juvenile and young-of-the-year bass in the stomachs of adult bass. We never found the “trifecta” of a bass in a bass in a bass but I’m sure it occurs. It is important to note that fish often take on different roles in a lake as they grow: early life stages may be planktivores, middle life stages may be benthivores, while adults may be piscivores (Figure 4). Even among these groups there are few fish who dine exclusively in one area or on one type of food (like humans) although the early life stages may eat almost all one staple item like zooplankton, the chicken nugget of the young fish diet (Figure 5). A simplified food chain in lakes is shown in Figure 6.The simplified food chain in lakes links fish with nutrients through a series of “middlemen” or mid-trophic levels. It makes sense that changes in one level in the chain can cause changes to cascade through to other levels in the chain. In general, the closer the levels are to each other in the chain, the stronger the influence of a change. We know that an increase in nutrients leads to more algal growth at one end of the chain in lakes. We also know that an abundance of planktivores (think bait) can grow some large piscivores (think dinner) at the other end of the chain. But does one end of the chain influence the other? The answer is that “it depends.”

Are Fish a Result of Management or the Tool? Traditional lake management has focused on nutrient management to control unwanted aquatic plants and excessive algal growth. Along the way, some of these nutrient control measures have lead to changes in upper trophic levels, all the way to fish. This is called “bottom-up” management of lakes and associated fish populations where management is focused on the bottom of

the food chain, the supply of nutrients. The connection between nutrients and fish is bolstered by the observation that the best “fishing” lakes are not necessarily the clearest or nutrient poor but rather, are those lakes that have a moderate or high level of nutrients. The effect does not continue forever; ever-increasing nutrients does not equal ever increasing numbers and size of fish; there is a limit. Once nutrients get very high in a lake, other factors related to eutrophication such as


low dissolved oxygen, high ammonia, and water clarity start to negatively influence fish abundance (Figure 7). The other approach to lake management is called, interestingly enough, “top-down” management. Carpenter et al. (1987) demonstrated the influence of top- down control of planktivores by piscivores and associated changes throughout the food chain in nutrient-poor north temperate lakes. Changes in the balance between piscivores and planktivores resulted in cascading effects down through the food chain to nutrients and algae. The basic premise is that the piscivores eat the planktivores, leaving less of them to eat the zooplankton. The increased

zooplankton population eats more algae, which changes the way nutrients are transported and stored throughout the food chain. The trophic cascade hypothesis was then tested in more nutrient rich temperate lakes (Kitchell 1992; Mills, Forney and Wagner 1987; Dettmers and Stein,1996). Sometimes an effect could be seen, sometimes it could not. The bottom line from this later research is that the more productive the lake, the more difficult it is to see an effect all the way down through the food chain by changing the fish population. The cascading effect is generally not seen when certain resilient species of fish like gizzard shad are present (Dettmers and Stein 1996).

Figure 4: An introduced rainbow trout that acts as both as a planktivore and a piscivore at times depending on what food is available.

Figure 5: Smaller members of the sunfish family, commonly called “panfish” include rock bass (red eyes) and bluegill. These fish are primarily planktivores and benthivores when young but will eat fish when they get large.

So how do we apply some of these concepts to lake management? In lakes and reservoirs, the goal of influencing water quality can theoretically be accomplished by manipulating nutrients or any of the components of the food web; however, the farther the trophic level is removed from the component or trophic level to be managed the stronger the manipulation must be to effect change. Likewise, the higher the nutrient concentration, the bigger the fisheries manipulation needs to be. In other words, you need a big stick. Traditional lake and reservoir algal management has focused on “bottom up” approaches that seek to influence algae and other primary producers through the management of sources of limiting nutrients (Cooke et al 2005). These approaches remain as essential parts of management plans aimed at problems associated with excessive growth of rooted plants, attached algae, and phytoplankton. These approaches should still form the basis and the primary focus of management plans for most lakes. Control of nutrients still represents the best opportunity to reduce the frequency, intensity, and duration of periods with excessive algal growth. The techniques of biomanipulation (changing the food chain as Shapiro [1975] first called it), which serve to change the amount of biomass at various levels of the food chain by changing the fish community, may be helpful in keeping lakes “in balance” or accelerating recovery from excessive nutrient loading. It is possible that a carefully conceived biomanipulation project may result in a


Figure 6. A simplified food chain in a lake.

Figure 7. The influence of increased eutrophication on Secchi disk transparency and fish yield (adapted from Holdren et al. 2001).

lake that grows fewer algae per unit of nutrient loading. The most commonly used manipulation designed to control algae involves a reduction in the biomass of planktivorous fish. Control

of planktivores is typically done either by selective removal of the planktivores or by increasing the abundance of piscivores either by stocking or through regulation of fish harvest. A side effect

of biomanipulation is that the fishing for large fish may get better, so everybody wins.

Final Thought Many people look at lakes with little thought as to what is below the water’s surface. The fact that most award-winning photos of lakes include a reflection of the sky in the lake surface reinforce the notion that a lake is defined by its surface and not what is below. One thing anglers always knew and lake managers now appreciate is that there are fish down there…and they matter. Fish are not only nice to have in lakes but are essential to the healthy functioning of our lakes, and can play an important role in lake management.

ReferencesCarpenter, S.R., J.F. Kitchell, J.R.

Hodgson, P.A. Cochran, J.J. Elser, M.M. Elser, D.M. Lodge, D.W. Kretchmer, X. He and C.N. von Ende. 1987. Regulation of lake ecosystem primary productivity by food web structure in whole lake experiments. Ecology. Vol. 68, No. 6.


Cooke, G.D., E.B. Welch, S.A. Peterson and S.A. Nichols. 2005. Restoration and Management of Lakes and Reservoirs, 3rd Edition. CRC Press; Taylor and Francis Group. Boca Raton, Fla. 591 pp.

Dettmers, J.M. and R.A. Stein. 1996. Quantifying linkages among gizzard shad, zooplankton, and phytoplankton in reservoirs. Trans. Am. Fish. Soc. 125:27-41.

Holdren, C., W. Jones and J. Taggart. 2001. Managing Lakes and Reservoirs. N. Am. Lake Manage. Soc. and Terrene Inst. In cooperation with Off. Water Assess. Watershed Prot. Div. U.S. Environ. Prot. Agency, Madison, WI.

Kitchell, J.F. (Ed.) 1992. Food Web Management: A Case Study of Lake Mendota. Springer-Verlag. New York. 553 pp.

Mills, E. L., J.L. Forney and K.J. Wagner. 1987. Fish predation and its cascading effect on the Oneida lake food chain. In W.C. Kerfoot and A. Sih (Eds.), Predation: Direct and indirect impacts on aquatic communities, pp.118-131.

Hanover: University Press of New England.

Shapiro, J., V. Lamarra and M. Lynch. 1975. Biomanipulation: An ecosystem approach to lake restoration, pp. 85-96. In P.L. Brezonik and J.L. Fox (Eds.). Water Quality Management Through Biological Control. Proc. Symp. Univ. Florida.

Don Kretchmer asked his father one day while fishing on a lake in central Ontario if he could ever make a living doing this sort of thing. His father replied, “Absolutely not!” So began his pursuit of a career working on and messing around in lakes. Don is a Certified Lake Manager with over 25 years of experience in watershed, nutrient, aquatic ecology and fisheries issues in lakes and rivers. He works for AECOM from an office in Wolfeboro, NH. In his spare time he is very active in the Lake Wentworth Association and is an avid sailor, skier, and

fisherman. He can be reached at [email protected]. x


The Role of Waterfowl Michael L. Schummer and Scott A. Petrie

Lake Ecology

The lower Great Lakes (“LGL”: Lakes Erie, Ontario, and St. Clair, plus their associated connecting

rivers) provide extensive and diverse habitat for migratory waterfowl in eastern North America. The region serves as a crossroad between the Mississippi and Atlantic flyways, with an estimated 12.8 and 7 million waterfowl passing through the Great Lakes each autumn and spring, respectively. In addition, approximately 1 million waterfowl remain on the LGL throughout winter in areas that remain relatively ice-free (e.g., Lake Ontario, as well as the Niagara, Detroit, and St. Clair rivers). The 29 species of waterfowl that inhabit the LGL are a diverse group that occur in nearly all types of aquatic systems. Omnivorous and herbivorous dabbling ducks, bay ducks (e.g., lesser scaup), geese, and swans occupy both coastal wetland and open lacustrine systems, whereas sea ducks (e.g., long-tailed ducks) range from omnivorous to nearly exclusively carnivorous and forage primarily in open lacustrine areas from 1 to 30 meters deep. Millions of waterfowl migrate within North America and have substantial energy requirements associated with flight and ovulation. These nutritional requirements and associated rates of consumption by waterfowl can cause strong top-down trophic influences in terrestrial and aquatic systems. Because waterfowl are abundant and ubiquitous in nearshore regions of the LGL (aquatic and terrestrial) and other lakes in North America it is vital that foraging requirements (type, timing, and amount) and potential to influence trophic cascades be considered in aquatic food webs. Herein, we summarize knowledge

The Role of Waterfowl in Lower Great Lakes Aquatic Food Webs

regarding influences of waterfowl on LGL aquatic food webs and develop estimates of foraging pressure within coastal and lacustrine systems using LGL non-migratory, invasive mute swans and wintering sea ducks as examples.

Waterfowl Use of Coastal Wetlands Coastal wetland systems (sometimes called protected lacustrine) provide substantial and essential habitat for a diversity of fish and wildlife within the LGL (Figure 1). Because less than 5 percent of the original coastal wetlands remain in this region, conservation and management of these habitats is critically important to enable a diversity of fish and wildlife species to complete their annual lifecycle. Waterfowl commonly foraging within coastal wetlands include dabbling ducks (surface-feeders such as mallards and teal), geese, and swans. In addition, some species of diving ducks including ring-necked ducks, lesser scaup, and redheads, also forage within these relatively shallow wetlands for some period of time during the annual cycle. Although some waterfowl species forage terrestrially on agricultural waste grains, many species also forage on submerged and emergent aquatic vegetation at the LGL. The leaves, seeds, stems, and tubers of aquatic vegetation in lakes throughout North America supply essential nutrients not available in corn, wheat, and soybeans. Studies of foraging pressure by waterfowl on aquatic plants in coastal wetland systems at Long Point, Lake Erie revealed that ducks, geese and swans may remove substantial portions of above and below-ground biomass of certain species during autumn. Specifically, nearly 100

percent above-ground biomass of wild celery and sago pondweed are removed by early December and below-ground biomass of these species declined by 76 percent during that time (Badzinski et al. 2006). Combined effects of autumn foraging and winter senescence can substantially reduce the amount and diversity of aquatic vegetation in spring and influence animal-plant associations within lake systems. Carrying capacities of lakes for waterfowl are greatly influenced by plant community composition and level of interspersion of open water to emergent vegetation within coastal (shoreline) wetland systems. Management of coastal wetlands for interspersion to promote a diverse plant community and nutrient flow between open lacustrine and coastal wetlands is common (Figure 2). Increased interspersion and connectivity between wetland and open lake areas increases fish (spawning) and wildlife habitat (cover, forage, breeding). Waterfowl using the coastal wetlands have the capacity to greatly influence vegetative and macroinvertebrate species composition and abundance of these systems. However, how waterfowl foraging activity may enhance or impact habitat and food availability for other species via trophic cascades is relatively unknown. Because millions of waterfowl forage within coastal wetland systems of lakes throughout North America annually and can influence vegetative and macroinvertebrate species composition and abundance, they should be acknowledged as a potentially integral player in lake food webs.

Waterfowl Use of Lacustrine Systems Foraging habitat for waterfowl within lacustrine systems of the LGL can be


Figure 1. Coastal wetland systems, such as Coletta Bay at Long Point, Lake Erie, provide substantial and essential habitat for a diversity of fish and wildlife at large lake systems throughout North America. Photo: Theodore Smith Photography.

Figure 2. Restoration to increase interspersion in wetland areas colonized by invasive plants is a common technique used to increase suitability of fish and wildlife habitat within large lake wetland systems such as coastal wetlands of the Great Lakes. A large (~10 acres) restored area is highlighted by the white box. Photo: Theodore Smith Photography.


divided into two general types; 1) shallow vegetated bays and 2) open shoreline locales. Several bay systems within the LGL including Long Point Bay, Lake Erie and Bay of Quinte, Lake Ontario provide extensive beds of submerged aquatic vegetation used by a diversity of ducks, geese, and swans. Key plant species include wild celery, muskgrass, pond weeds, and coontail (Petrie and Knapton 1999). The abundant and diverse submerged aquatic vegetation within LGL bays is foraged on extensively by waterfowl during migration. Specifically, ducks that are primarily herbivorous such as canvasbacks and redheads depend on these aquatic beds of vegetation to fuel migration. Estimates of biomass and coverage of submerged aquatic vegetation have been developed for some lacustrine systems (e.g., Long Point Bay), but additional determinations of biomass removal by waterfowl would enable more accurate inclusion of waterfowl in models of lake-wide food web dynamics. In open shoreline locales, bay and sea ducks forage on macroinvertebrates including amphipods, chironomids, gastropods, and dreissenid mussels (zebra and quagga mussels combined). To a lesser extent these ducks also consume fish, fish eggs, crayfish, and aquatic vegetation. Abundances of many species of staging and wintering bay and sea ducks increased substantially following introduction of dreissenid mussels to the LGL, seemingly as a result of direct and indirect increases in food abundance. Current estimates of over-wintering bay and sea ducks are regularly greater than a quarter-million birds during annual January counts of the LGL. Winter waterfowl surveys do not include offshore locales so the number of birds overwintering on the LGL is likely substantially greater. Although many bay and sea ducks are molluscivorous and consume dreissenid mussels (direct increase in food abundance), increases in abundances of other macroinvertebrates that inhabit areas of live and dead dreissenid mussels such as amphipods and chironomids (indirect increase in food abundance resulting from dreissenid mussel colonization) also are consumed in abundance by these ducks at the LGL. Thus, dreissenid mussel-amphipod-chironomid communities that develop on

substrate also appear to have contributed to increased use of LGL by bay and sea ducks during migration and winter. In areas of concentrated bay and sea duck use such as power plant outlets and other relatively shallow water locales, foraging ducks can reduce the abundance of some types of macroinvertebrates and have been suggested as a mechanism for long-term decline of dreissenid mussels in some locales (Petrie and Knapton 1999). In most cases, ducks do not cause significant decreases in abundances of macroinvertebrates (Schummer et al. 2008a); nonetheless, overall consumption of prey by bay and sea ducks can be substantial at certain times and locales (see long-tailed duck example below). Because waterfowl using lacustrine systems overlap in consumption of vegetation and macroinvertebrates with fish and other wildlife and may directly prey upon these species (e.g., fish and fish eggs), continued modeling of waterfowl contributions to food webs of North American lakes would be beneficial to fish and wildlife biologists charged with conservation of natural resources.

Consumption Estimates of Aquatic Vegetation by Non-migratory, Invasive Mute Swans in LGL Coastal Wetlands Mute swans are an exotic, herbivorous species whose population has increased substantially within LGL since introduction in the mid-twentieth century. The Great Lakes population of mute swans is currently estimated to be greater than 10,000, which has been a cause for concern for natural resource managers in the region. Mute swans are large birds that require considerable amounts of vegetation daily to meet their nutritional needs (Figure 3). For example, individual mute swans are estimated to consume 4.0 kg of aquatic vegetation daily and during breeding may consume up to 43 percent of their body mass each day. Further, mute swans uproot substantial amounts of submerged aquatic vegetation, much of which is not consumed as they forage for specific plant parts. Thus, 10,000 mute swans at the Great Lakes are capable of removing 80,000 kg of vegetation from coastal wetlands and lacustrine bays daily, or 29,200 metric tons (wet wt.) of vegetation from the Great Lakes annually. Such foraging pressure by this

essentially non-migratory invader has the potential to greatly influence above and below ground vegetative biomass in Great Lakes’ wetlands, especially where swans occur in high densities. As has happened in Chesapeake Bay, these changes in biomass could result in substantial shifts in plant communities and alteration of aquatic food webs in Great Lakes coastal areas and other aquatic systems where mute swans are abundant.

Modeling Amphipod Predation by Wintering Long-tailed Ducks at Lake Ontario To model consumption of amphipods by long-tailed ducks (Figure 4) at Lake Ontario we used food use, behavioural, and lipid dynamics data from these ducks at Lake Ontario (Schummer 2005; Schummer et al. 2008b), true metabolizable energy estimates for amphipods, and standard metabolic equations for ducks. For simplification, seasonal averages are used for calculations unless otherwise noted. Basal metabolic rate (BMR) in watts was determined as BMR = 3.56(body mass in grams)0.73 and 4.40(body mass in grams)0.73, during night and day, respectively. Cost of diving to feed and resting over water were designated as 3.5x and 1.4x BMR, respectively. To calculate daily energy costs, activities were categorized as 70 percent diurnal feeding, 30 percent diurnal resting, and 100 percent nocturnal resting (Schummer 2005). The resulting estimate of total daily energy output for long-tailed ducks in our study averaged 582 kJ/day. If long-tailed ducks at Lake Ontario maintained lipid reserves throughout winter, energy input needs would equal energy output. However, long-tailed ducks at Lake Ontario on average lost ~20 g of lipids throughout winter (Schummer 2005). We converted lipids to energy (kJ) assuming 37.7 kJ/g of lipid to discount energy needs by 10.2 kJ/day (balance = 571.5 kJ/day). Amphipods that have a true metabolizable energy of 9.6 kJ/g in ducks comprised 28.1 percent of long-tailed duck diets (mostly Gammarus fasciatus). Thus, we estimate that each long-tailed duck using Lake Ontario during an approximate 75 day wintering period would consume 1,254.6 g of amphipods (16.7 g/day), or


Figure 3. Mute swan foraging. Mute swans consume up to 43 percent of their body mass each day and can substantially reduce above- and below- ground biomass of aquatic vegetation where they forage. Photo: Theodore Smith Photography.

71.9 metric tons of amphipods would be consumed annually when considering all 57,331 long-tailed ducks that, on average, winter at Lake Ontario. Our estimates do not include other species of wintering bay and sea ducks nor birds migrating through the region during autumn and spring. Thus, our modeling efforts suggest that removal of macroivertebrate biomass by waterfowl can be substantial and should be considered in lake food webs.

Summary Coastal and lacustrine wetlands associated with the LGL provide important foraging habitat for migrating and wintering waterfowl. Based on waterfowl abundance in North America, as well as their duration of stay and nutritional requirements, our models suggest that waterfowl can have a substantial influence on aquatic food webs in lake systems. Invasive species

can alter aquatic food webs and waterfowl are influenced by associated bottom-up responses (e.g., dreissenid mussels) and top-down effects (e.g., mute swans). We can expect that wetland habitats associated with North American lakes will continue to be influenced by the introduction of invasive species, climate change, water level changes, and anthropogenic influences. Associated changes to aquatic food webs of the LGL and other inland lake systems will undoubtedly

Figure 4. Diving ducks, such as the long-tailed duck shown here, consume substantial numbers of macroinvertebrates while migrating through or wintering at lakes and reservoirs. Photo: Theodore Smith Photography.

influence regional abundances and species composition of waterfowl. Similarly, because waterfowl can have substantial top-down effects on invertebrate and plant communities, we believe that understanding their role in aquatic food webs is important to system-wide conservation and management of North American lakes.

ReferencesBadzinski, S.S., C.D. Ankney and S.A.

Petrie. 2006. Influence of migrant tundra swans (Cygnus columbianus) and Canada geese (Branta canadensis) on aquatic vegetation at Long Point, Lake Erie, Ontario. Hydrobiologia 587:195-211.

Petrie, S.A. and Knapton, R.W. 1999. Rapid increase and subsequent decline of zebra and quagga mussels in Long Point Bay, Lake Erie; possible influence of waterfowl predation. Journal of Great Lakes Research 25:772-782.

Schummer, M.L. 2005. Comparisons of resource use by Buffleheads, Common Goldeneyes and Long-tailed Ducks during winter on northeastern Lake Ontario. Unpublished Ph.D. Dissertation. University of Western Ontario, London, Ontario.

Schummer, M.L., S.A. Petrie and R.C. Bailey. 2008a. Interaction between macroinvertebrate abundance and


habitat use by diving ducks during winter at northeastern Lake Ontario. Journal of Great Lakes Research 34:54-71.

Schummer, M.L., S.A. Petrie and R.C. Bailey. 2008b. Dietary overlap of sympatric diving ducks during winter on northeastern Lake Ontario. Auk 125:425-433.

Michael (Mike) Schummer is a scientist with Long Point Waterfowl (LPW), Port Rowan, Ontario. LPW is a non-profit, non-government organization dedicated to waterfowl- and wetland-related research, conservation and training, as well as to the celebration of our outdoor heritage. Mike’s research generally focuses on evaluating positive and negative anthropogenic effects on wildlife populations and wetland systems, with specific focus on waterfowl. Current

research includes Great Lakes sea duck ecology, influences of climatic variability on fall-winter distributions of waterfowl in North America, contaminants in Great Lakes waterbirds, and evaluation of coastal wetland restoration in the lower Great Lakes region. You may contact Mike at: [email protected]

Scott Petrie is the executive director of Long Point Waterfowl and is an adjunct professor at the University of Western Ontario, where he teaches wildlife ecology and management. Scott’s work has focused primarily on the ecology of waterfowl in semi-arid environments and the staging and wintering ecology of north-temperate occurring waterfowl. Scott and his graduate students are presently studying various ecological aspects of waterfowl that stage and winter on the lower Great Lakes. x


Student CornerChelsey A. Campbell

Introduction

Fishers are well-known for their superstitions, and the list of things thought to bring bad luck to a

voyage is long. Some taboos, such as setting sail on a Friday or whistling into the wind, have persisted for hundreds of years (Olmsted 1841). Among the more well-known superstitions is the belief that it is bad luck to bring bananas on board a vessel. No one knows the exact origins of the banana taboo, though many theories have been proposed. Some believe it originated when trade vessels began carrying the fruit from the New World back to markets in Europe (Ronca 2008). Since bananas spoil quickly, these ships had to travel fast; this both made the journey more dangerous and allowed less time for fishing breaks (hence the association between bananas and bad luck or low fishing success) (Ronca 2008). Others think ship captains began circulating the superstition to avoid infestations of creatures like spiders and snakes that often tagged along with a cargo of bananas (Brincefield 2008; Ronca 2008). The taboo has also been linked with the bananas’ tendency to release ethylene gas as they ripen, which had the unwanted side effect of causing other perishable foods to spoil quickly (Brincefield 2008). Whatever its true origins, the taboo remains common worldwide. Some fishers will even extend the superstition to include anything associated with bananas, such as Banana Boat® sunscreen or Banana Republic® clothing (Brincefield 2008). However, it remains unclear

Do Bananas Bring Bad Luck to a Fishing Vessel?whether there is any actual link between bananas and luck. For this reason, we designed a study to experimentally test the taboo; the objective was to look for a relationship between bananas and luck or fishing success aboard a vessel.

Study Design We conducted our study at Watson’s Pond, located at the Fisheries and Aquatic Sciences Program at the University of Florida in Gainesville, Florida. The pond is stocked with freshwater fish of multiple species and served as a controlled environment for our experiment. Study design consisted of two single- person kayaks fishing simultaneously, with one fisher in each kayak. We provided each fisher with a 1.7-meter fishing pole (Shakespeare Sturdy Stik) and cut-up hot dogs to use as bait. A data recorder was assigned to each kayak to record the number, species, and size (fork length) of fish landed (brought on board the vessel), as well as incidents of “bad luck” that occurred during each treatment such as bait loss or fish loss. Testing took place during the middle of the day, from 13:00 to 15:00, in November 2010. We also provided each fisher with one Styrofoam cooler, labeled “A” or “B,” respectively, which was placed on the back of the kayak. Cooler A contained four bananas while cooler B contained DI water bottles to mimic the weight of bananas; fishers were not told which cooler contained bananas. Fishers fished for a period of 15 minutes; after this period the fishers switched coolers and then fished for an additional 15 minutes.

This was then repeated two times, for a total of six blocks (six banana treatments and six control treatments, with three repetitions per fisher).

What Did We Find? Data were analyzed using a paired t-test. Results show no significant differences in “bad luck” parameters such as incidents of bait loss (p=0.102), fish loss (p=0.2324), or size of fish (p=0.2969 for bluegill and p=0.357 for catfish) between the banana and control treatments. However, our test did find significant differences in number of fish landed during each treatment (p=0.02915). In addition, data demonstrated that in five out of six treatment blocks, fishers had more success with the control treatment than with the banana treatment (Figure 1).

Discussion Results of this study seem to indicate a relationship between the presence of bananas and fishing success. This study cannot conclude that bananas are the cause of the lowered fishing success, however, simply that there is a correlation. This study also implies no relationship between the presence of bananas and an increase in incidences of bad luck, such as fish loss or bait loss (in addition, no vessels were flipped or sunk during either treatment). It is important to keep in mind that this study is in no way conclusive; the sample size was small, and few fish were landed during any treatment. Additionally, the reason banana presence seems to correlate with fishing success remains unknown. The bananas were contained


Figure 1. Number of fish landed per treatment. The total number of fish landed for each treatment. Empty bars signify 0 fish landed during treatment.

within a cooler, so it is unlikely that any banana oils leaked into the water to alert the fish to their presence; additionally, fishers were blind to the presence of bananas, so it shouldn’t have biased fisher behavior. However, it is interesting that a relationship was found between the

presence of bananas and lowered fishing success, as many believe this superstition to be purely psychological. In summary, while the presence of bananas does not seem to increase bad luck on board a vessel, it does seem to correspond with lower fishing success.

Based on the results of this study, it would be advisable to avoid including bananas on board a vessel, in particular while fishing.

ReferencesBrincefield, J. 2008. The story of bananas

and bad luck. Chesapeake Bay & Atlantic Ocean Charter Fishing. Available at: http://www.azinet.com/captjim/bananas.htm (October 2010).

Olmsted, F.A. 1841. Incidents of a whaling voyage. D. Appleton and Company, New York, NY. 349 pages

Ronca, D. 2008. Why are fishermen superstitious of bananas? How Stuff Works. Available at: http://people.howstuffworks.com/fishing-superstition1.htm# (October 2010).

Chelsey Campbell is a master’s student in the Fisheries and Aquatic Sciences Program at the University of Florida. x


WorldviewsSharon Reedyk &Robert Morgan

Centre for Lake Restoration (CLEAR) started in 2006 and involves four Danish universities or

research institutions, including a number of NALMS members. The Centre is interdisciplinary and studies limnology, biogeochemistry, and hydrogeology to improve our understanding of the regulations of structure and function of lakes and to improve lake restorations and management. The centre is financially supported largely by a donation of 9.15 million USD from the private Danish Villum Foundation. CLEAR was established because there was a need for a more scientific approach to lake restoration and lake management. We also needed better procedures to ensure the quality of the pristine Danish lakes still present, because these lakes host a unique vegetation dominated by small rosette plants (isoetids). As an additional benefit, the results from CLEAR would be timely for lake managers who have been challenged to reach the goals for good ecological quality by 2015 as defined in the European Water Framework Directive. The fact that land use in Denmark is dominated by agriculture (66 percent of area) and the annual pig production is 27.7 million (the human population is only 5.5 million) entail serious eutrophication problems for the aquatic environment. As a result, most Danish lakes are far from having good ecological quality.

Lake Nordborg Among the main objectives for CLEAR, therefore, was to study cost-efficient methods such as aluminum (Al) addition and fish stock manipulation in the restoration of eutrophic lakes. An example of such a study is that on Lake Nordborg (Figure 1). Loading, retention and in-lake cycling of phosphorus (P),

A Scientific Approach to Lake Restoration in Denmark

Frede Ø. Andersen, Sara Egemose and Henning S. Jensen

Figure 1. Application of poly-aluminum chloride (52 g Al m-2) to eutrophic Lake Nordborg, Denmark, in October 2006. The surface area of the lake is 55 ha, average depth is 5 m and maximum depth is 8.5 m. The catchment (1180 ha) is dominated by agriculture (63 percent) and urban areas (25 percent).

nitrogen (N), silica and dissolved organic carbon were studied one year before and three years after P-inactivation by Al hydroxide in 2006. Simultaneously, external P loading was reduced by 40 percent via establishment of precipitation ponds in two inlets. After Al treatment, the internal P loading during the summer declined by 90 to 94 percent due to adsorption to Al hydroxide. Consequently, lake water total P and dissolved inorganic P decreased by 73 percent and 97 percent, respectively (Figure 2). Also, silicate and ammonium release from the sediment declined markedly. The Secchi depth


increased in the summer period in the first post-treatment year, but declined afterwards to pre-treatment levels even though the summer mean lake water total P concentration was reduced from ~240 µg/L before treatment to 26-65 μg/L in the first three post-treatment years. We conclude that further reduction of the external P loading is needed to obtain the full effect of the Al treatment in Lake Nordborg. Thus, in the coming years, development of more efficient sedimentation and infiltration basins to reduce external nutrient loadings will be an important target.

Lobelia Lakes Another important focus of CLEAR’s research was to obtain a better understanding of overall water and nutrient balances in the more pristine lakes and the distribution and eco-physiological adaptations of their prominent isoetid plants. One of the conspicuous species of isoetids is Water Lobelia (Lobelia dortmanna, Figure 3) and lakes dominated by isoetids are therefore often called Lobelia-lakes. These types of lakes may be found in northern temperate regions, also in northern North America. In Denmark, many of the Lobelia-lakes are exposed to high groundwater seepage. The goal was

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Figure 2. Concentrations of total P and dissolved inorganic P in the epilimnion of Lake Nordborg before and after the Al treatment. The total P and dissolved inorganic P decreased by 73 and 97 percent, respectively, as a result of the aluminum treatment.

Figure 3. Flowering water lobelia (Lobelia dortmanna). The 15-20 mm long flowers are pale blue and held above the water surface by the raceme. The plant species is characteristic for oligotrophic lakes with clear water.

to identify what is needed to maintain the fairly pristine conditions and high biodiversity of Lobelia-lakes, but studies have also been initiated on how to restore previous Lobelia-lakes that have become turbid and lost the isoetid vegetation. One of our studies was carried out in the oligotrophic seepage lake, Lake Hampen (Figure 4), to determine seepage in and out of the lake and to determine the mass budgets for nutrients. The lake is primarily surrounded by forest, although there are agricultural fields bordering a small portion of the lake perimeter. The water and mass balances indicate that groundwater contributes ~70 percent to the total water input and ~67 percent and ~85 percent to the N and P input, respectively. The majority of N is leached from the agricultural fields bordering the lake (Figure 5). Concentrations as high as 1750 µM nitrate were measured in the rhizosphere of the littoral zone at this location. It is estimated that the macrophytes are able to take up ~50 percent of the N input, whereas the P uptake by plants was 310 percent of the input, indicating that plants are highly dependent on accumulated and remineralized P in the lake. Although the plant uptake may have slowed down the eutrophication of the lake, the excess nutrients may over time give rise to


Figure 4. Oligotrophic Lake Hampen (a Lobelia-lake) with emergent flowers of water lobelia in the littoral zone. Basal rosettes of the 2-7 cm long leaves are seen submerged at the sediment surface. The lake receives ~70 percent of the water input as groundwater seepage. Also, the nutrient input is primarily via groundwater. The surface area of the lake is 76 ha, average depth is 4.3 m and maximum depth is 13 m. The catchment (990 ha) is dominated by forest (62 percent) and agriculture (30 percent).

Figure 5. Dissolved inorganic nitrogen (DIN) concentrations in near-surface groundwater along the north-eastern shoreline of Lake Hampen where a farm is situated. The samples were taken at 1.75 m depth in piezometers. Groundwater is seeping from land out through the littoral zone in this part of the lake. The graph shows a bell-shaped pattern of the DIN concentration along the shore with low concentrations where forest is bordering the lake and high concentrations where fields are bordering the lake indicating a strong influence of N leaching from the fields.

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eutrophication and a shift toward pelagic production. In the next five years we will continue the research on methods that can give rapid improvements in lake water quality, but also address questions of how to manage lakes and watersheds in a future warmer and wetter climate to obtain good ecological condition of the lakes. According to Climate Scenario A2, annual mean temperatures in Northern Europe are predicted to increase by 2-5o C in lakes and annual precipitation to increase by ten percent in the period 2070-2100 relative to 1960-1990. These changes will put further pressure on the water quality of lakes as nutrient inputs are expected to increase, lakes will stratify for longer periods and the oxygen availability will decline in warmer water. Also, input of colored dissolved organic matter (CDOM), which has a major influence on light climate of many lakes, will change with altered hydrology and temperature. Finally, some species, including isoetid plants, may have difficulties in competing in warmer lakes and may be replaced by more tolerant and potentially problematic species. Invasive species that are already here may obtain a wider distribution. This has already happened to the zebra mussel (Dreissena polymorpha), which can have a pronounced impact on the biological structure of lakes. Thus, CLEAR will continue to contribute with a scientific basis for lake restoration and management. Members of CLEAR are thanked for providing the reported data. A list of publications from CLEAR is available on http://www.lake-restoration.net/english/index_UK.html.

Dr. Frede Ø. Andersen is a limnologist with special interest in macrophytes, nutrient cycling and lake restoration. He is an associate professor at Institute of Biology, University of Southern Denmark and Head of CLEAR. He teaches courses in freshwater ecology and Danish nature types. You can reach Frede at: [email protected]

Dr. Sara Egemose is a freshwater ecologist with special interest in lake restorations with Al and other P-binding compounds, and sedimentation basins. She is working as a postdoc at CLEAR at Institute of Biology, University of Southern Denmark. She teaches courses in freshwater ecology. You can reach Sara at: [email protected]. Dr. Egemose is a current member of NALMS.

Dr. Henning S. Jensen is a limnologist with special interest in sediment biogeochemistry, nutrient cycling, and lake restorations with Al and other P binding compounds. He is an associate professor at Institute of Biology, University of Southern Denmark. He teaches courses in freshwater and terrestrial ecology and Danish nature types. You can reach Henning at: [email protected]. Dr. Jensen is a current member of NALMS. x


AffiliateNews

Florida Lake Management Society (FLMS)FLMS (Florida Lake Management Society’s) 22nd Annual Conference

is coming up in June. This year’s venue is the St. Johns County Conference Center at the Renaissance Hotel just south of St. Augustine. The conference theme is “Discovering the St. Johns River – a River of Lakes.” The conference starts on Monday, June 13 with four workshops: a training course with field experience on the FDEP Lake Vegetation Index (LVI); an elementary and middle school water resource curriculum – the “Great Water Odyssey”; a secondary school curriculum – “Water Atlas in the Classroom”; and “NPDES and TMDL Regulatory Considerations.” Technical sessions run from Tuesday, June 14 through Thursday, June 16, and will cover these and other topics: • The St. Johns River • Watershed Assessment • Watershed Management • Education and Outreach • Nutrient Criteria A poster session will be held along with a welcoming social on Tuesday evening, June 14.

Indiana Lake Management Society (ILMS)The Indiana Lakes Management Conference occurred on March 24-26, 2011 at the Potawatomi Inn

at Pokagon State Park. More than 150 lake residents and enthusiasts joined the Indiana Lakes Management Society for the 23rd annual conference. Many thanks to our sponsors, including Aquatic Control, Aquatic Weed Control, Clarke Aquatic Services, Aquatic Enhancement and Survey, Indiana Watershed Leadership Academy, Cygnet Enterprises, and Davey Resource Group. This year’s conference highlighted opportunities to make waves within your community. ILMS welcomed Eric Eckl of Water Words That Work, who hosted a full-day session focused on communication. Concurrently, individuals from around the state highlighted ongoing efforts to manage Indiana’s lakes. Sessions focused on fisheries management, state rules and laws affecting Indiana’s lakes,

partnerships between lake associations and professional managers, and the latest happenings of the Lakes Management Work Group. Two Saturday workshops detailed management of lakes for plants and algae concerns and stressed the importance and opportunities for partner development. During the conference, ILMS members elected new board members Kyle Turner of Beaver Dam/Loon Lake Conservation Club, Brigitte Schoner of Whippoorwill Lake, and Steve Lee of Aquatic Control and re-elected Heather Buck of Christopher B. Burke Engineering, Ltd. Additionally, Sara Peel of the Wabash River Enhancement Corporation and Ed Sprague of Skinner Lake were elected president and vice-president of the society, respectfully. ILMS would like to thank out-going

An enthusiastic group attending the 23rd Annual Indiana Lake Management Conference filled the Lake James meeting room at the Potowatomi Inn.


board members Jed Pearson of Indiana DNR, Nate Long of Aquatic Control, and Ed Spanopoulos of Cygnet Enterprises for all of the efforts during their time on the board. At its annual banquet, ILMS recognized the ILMS Student Scholarship recipients Abigail Grieve, Indiana University School of Public and Environmental Affairs, Caitlin Grady of Purdue University, and Matt Linn of Manchester College. Students received a $500 scholarship and free conference attendance. ILMS also recognized the Clear Lake Township Land Conservancy (CLTLC) for their commitment to improving conditions in and around Clear Lake. CLTLC’s partnership with the Steuben County Drainage Board resulted in improved stream stabilization to a tile outlet and through their efforts to restore a wetland within their watershed; they’ve enlisted the assistance of the US Fish and Wildlife Service. Their efforts have expanded outside of their immediate landowners to include watershed landowners in their efforts as well. While CLTLC is just getting started, their efforts serve as an inspiration to other lake associations and watershed groups showing just what can be accomplished from a small but dedicated group of volunteers. ILMS also recognized Joe Costello of the Sylvan Lake Improvement Association for his volunteer efforts and service at Sylvan Lake over the past 40 years. Accomplishments during his tenure include: installation of a lake-wide sewer in 1974 (the second of its kind nationwide); conversion of the lake from a carp-dominated fishery to one of the best fisheries in the state through a whole-lake fish eradication and restocking in 1984; salvation of Boy Scout Island through the $1.25 million purchase of the Island and future transfer of said island to the Gene Stratton Porter State Memorial. Joe’s efforts to work to improve Sylvan Lake through his leadership and fund-raising were keys in bringing this lake to its current high quality. Additionally, ILMS was pleased to recognize our first outstanding implementation project recognizing the Town of Cedar Lake. Since the late 1980s, the Cedar Lake Enhancement Association

has been working to protect and enhance Cedar Lake and its watershed. The latest effort by the Cedar Lake Public Works Department to reduce stormwater impacts to Cedar Lake represents opportunities to innovate with low-cost solutions to standard problems. Clearing an existing right-of-way of overgrown trees and invasive honeysuckle and removing eroded material throughout the project area paved the way for the installation of rock check dams and native plants. This effort was completely funded by the Town of Cedar Lake and implemented by their employees, serving as a learning experience with techniques that will be reproduced at additional sites around the lake. For their innovation and perseverance, ILMS was pleased to recognize the Town of Cedar Lake. The Indiana Clean Lakes Program convened a special breakfast for volunteers participating in the Volunteer Lake Monitoring Program on Saturday morning. The breakfast offered the opportunity for volunteers to meet with each other and with CLP staff to talk about the program. Later Saturday morning, three citizens were trained to become expanded volunteer monitors.

New York State Federation of Lake Associations, Inc. (NYSFOLA)The New York State Federation of Lake Associations, Inc. held its annual

conference at the White Eagle Conference Center in Hamilton, NY on April 29-May 1, 2011.

An entire day was dedicated to invasive species issues, and Dr. Charles Boylen of the Darrin Freshwater Institute gave the keynote presentation, “The Cost of Aquatic Invasive Species Management in New York Lakes.” Lake Steward Awards were presented to Lou Feeney, of the Three Lakes Council (lakes Waccabuc, Rippowam and Oscaleta); Bill McGhie of the East Shore Schroon Lake Association and Bob Rosati of the Melody Lake Association. Bob also received NYSFOLA’s highest honor, the Lake Tear of the Clouds Award, for his many years serving on the NYSFOLA Board of Directors and notably for his work with the New York State Department of Environmental Conservation and NYSFOLA member lake associations on the recently adopted NYS Dam Safety regulations. NYSFOLA also congratulated Dr. Willard Harman on the recent SUNY approval of his Masters Degree in Lake Management Program and recognized him for his dedication to NYSFOLA and Otsego County environmental organizations. x

NYSFOLA Board member and 2011 Lake Tear of the Clouds Award recipient, Bob Rosati, performing the annual Melody Lake Dam inspection.


Literature SearchBill Jones

Canadian Journal of Fisheries and Aquatic Sciences

Higgins, S.N., M. . Vander Zanden, L.N. Joppa and Y. Vadenboncoeur. 2011. The effect of dreissenid invasions on chlorophyll and the chlorophyll: Total phosphorus ration in north-temperate lakes. Can J Fisheries Aquat Sci, 68(2):319-329.

Coastal Management

Kuo Lawrence, P. 2011. Achieving teamwork: Linking watershed planning and coastal zone management in the Great Lakes. Coastal Management, 39(1):57-71.

Drescher, S.R., N.L. Law, D.S. Caraco, K.M. Cappiella, J.A. Schneider and D. Hirschman. 2011. Research and policy implications for watershed management in the Atlantic Coastal Plain. Coastal Management, 39(3):242-258.

Critical Reviews in Environmental Science and Technology

Walker, W. and R. Kadlec. 2011. Modeling phosphorus dynamics in Everglades wetlands and stormwater treatment areas. Crit Rev Environ Sci Tech, 41:430-446 (Supp 1).

Diversity & Distributions

Muirhead, J.R., M.A. Lewis and H.J. Macisaac. 2011. Prediction and error in multi-stage models for spread of aquatic non-indigenous species. Diversity & Distributions, 17(2):323-337.

Freshwater Biology

Chiandet, A.S. and M.A. Xenopoulos. 2011. Landscape controls on seston stoichiometry in urban stormwater management ponds. Freshwater Biol, 56(3):519-529.

Johnson, P.T.J. and S.H. Paull. 2011. The ecology and emergence of diseases in fresh waters. Freshwater Biol, 56(4):638-657.

Hydrobiologia

Bargu, S., J. White, C. Li, J. Czubakowski and R. Fulweiler. 2011. Effects of freshwater input on nutrient loading, phytoplankton biomass, and cyanotoxin production in an oligohaline estuarine lake. Hydrobiol, 661(1):377-389.

Gibbs, M., C. Hickey and D. Özkundakci. 2011. Sustainability assessment and comparison of efficacy of four P-inactivation agents for managing internal phosphorus loads in lakes: sediment incubations. Hydrobiol, 658(1):253-275.

James, R.; W. Gardner, M. McCarthy and S. Carini. 2011. Nitrogen dynamics in Lake Okeechobee: forms, functions, and changes. Hydrobiol, 669(1):199-212.

International Journal of Environmental Engineering

Chin Y. 2011. Forum: Urban storm water management quantity and quality. Intl J Environ Engin, 3(2):205-206.

Journal of Biobased Materials and Bioenergy

Love, B. and A.P. Nejadhashemi. 2011. Environmental impact analysis of biofuel crops expansion in the Saginaw River watershed. J Biobased Mats Bioenergy, 5(1):30-54.

North American Journal of Fisheries Management

Daugherty, D., D. Buckmeier and P. Kokkanti. 2011. Sensitivity of recreational access to reservoir water level variation: an approach to identify future access needs in reservoirs. N Amer J Fish Manage, 31(1):63-69.

Water Resources Management

Guan, X., J. Li and W. Booty. 2011. Monitoring Lake Simcoe water clarity using Landsat-5 TM images. Water Resour Manage, 25(8):2015-2033.

Paynter, S., M. Nachabe and G. Yanev. 2011. Statistical changes of lake stages in two rapidly urbanizing watersheds. Water Resour Manage, 25(1):21-39.

William (Bill) Jones, CLM, is LakeLine’s editor and a former NALMS president, and clinical professor (retired) from Indiana University’s School of Public and Environmental Affairs. He can be reached at: 1305 East Richland Drive, Bloomington, IN 47408; (812) 855-1600; e-mail: [email protected]. x


Memorial Day, July 4th, and Labor Day). It is well known that phosphorus found in most lawn fertilizers creates an oversupply of that nutrient in surface and groundwater. It quickly reaches our lakes and rivers and can cause accelerated aquatic plant and algae growth and overall reductions in water quality. The LLSWD and Greenstone Corporation are committed to continued education about freshwater protection and try to work with local residents to achieve beautiful lawns and a healthier watershed. These two groups offer a way to help the lake at no cost by taking advantage of the annual phosphate-free (P-free) fertilizer give-away by providing a voucher for a free bag of P-free fertilizer for watershed residents.

As we reflect on our lakes we must also pay our respects to those lakes that have suffered at our hands. Heed this warning: Take action and don’t let this or something similar happen to your lake!

OBITUARY

Lake Eliot drained, age 11,972, after a long and grueling battle with contaminated runoff, effluent, recreational abuse, and heavy consumption. Eliot is survived by 1,532 lakes and reservoirs, all residing locally in Colorado.

An active member of the aquatic community, Eliot contracted damaging amounts of algae and dehydration due to high levels of thirstiness and nutrients from stormwater, green-lawn syndrome (GLS), failed septic systems, and direct contact with excreting humans.

Federal and local programs frantically tried to revive the popular lake, but the millions of taxpayer dollars spent were just years too late.

In lieu of flowers, loved ones are asked to reduce water consumption, eliminate fertilizers from impervious surfaces, fix vehicular oil leaks, join a local watershed or lake association, and appreciate how important and fragile our remaining lakes and reservoirs are to your daily life.

Special thanks to Steve Lundt for sharing information and photos from Colorado, Joann Harris from Indiana for the poem, BiJay Adams for information from Washington and Rhonda Weinstein for information and photos on Eastman Pond in New Hampshire. If you have stories or other pieces you’d like to share please send them to [email protected]. Your stories may appear in the NALMS electronic newsletter or on the NALMS website under the Lakes Appreciation Month Page.

Steuben ShoresA poem

In our county woods and lakes abound.A place for living we have found.

Overlooking a glistening lakeWe value all that nature can make.

Oaks and hickories bring birds to nest.Shore birds give us a show that’s the best.

Mowed lawns are neat and tidy it’s true.But lakes need a buffer to keep them clean too.

Naturalizing the shore of our lake Brings pleasant surprises for us to partake.

Yellow flag iris, mint and much moreAttract hummingbirds here to our shore.

A little known fact we want to say,Tall growing plants keep geese at bay.

With conservation, because we care,Lakes benefit when we all do our share.

Poem by Joann M. HarrisAngola, Indiana


If you still need ideas for how YOU can pay homage to lakes this Lakes Appreciation Month, or any time of year, try one or more of these ideas!

ØBecome a member of NALMS if you are not already one.

ØGive the gift of NALMS to a lake lover like yourself! Each of us likely has a colleague, student, client, lake or watershed member, friend or even family member that would benefit from some level of affiliation with this group that strives to protect and enhance lakes and other waterbodies for our future.

ØParticipate in a Secchi Dip-In, this year, it runs from June 25 to July 17. This is the 18th year of the Dip-In,

and the three-week event in June and July demonstrates that volunteers can collect valuable water quality data. The Dip-In is a network of volunteer programs and volunteers, that together gather and provide continent-wide (and world-wide) information on

water quality. Learn more at http://www.secchidipin.org.

ØVolunteer to serve on a NALMS committee, of which there are many. The NALMS Education Committee, Government Affairs Committee, Volunteer Monitoring Committee and others would welcome you. This can be your way to making a commitment to some aspect of lake appreciation and lake management.

ØTalk to your local politicians and representatives about supporting funding for lake and watershed projects on both a state and federal level. Our water resources are precious, are under high demand, and are at risk. Without protection and funding these resources will ever be in jeopardy.

ØTake a day (or week!) off and visit a local lake or pond.

ØGo boating, kayaking, canoeing, sailing, or rowing.

ØGo swimming or SCUBA diving

ØGo fishing and maybe teach someone (kids, grandkids, friends) how to fish.

ØIf you are not a lake manager, contact your local lake management agency and see if you could shadow a limnologist for a day to see what they do.

ØIf you are a lake manager, coordinate activities in your office or on a local waterbody for others to participate (bring sampling equipment, id keys and other interactive materials).

ØOrganize a lake clean-up event.ØOrganize a watershed clean-up event.ØOrganize a watershed storm drain stenciling program.ØHave your septic system pumped if you live close to a

waterbody.ØGo to a local or state park beach on the shores of a

lake, pond or reservoir.ØGo birding or picture taking around a lake or pond.ØIf you are an artist, draw or paint a lake scene and put

it up in your home or office to remind yourself of the great time you had at the lake while you were creating this work of art.

ØOrganize a field trip for students.ØOrganize a family day at a local

lake or pond.ØGo take some pictures of lakes

and submit them for consideration in the annual NALMS Photo Contest.

ØAsk your governor to issue a proclamation designating July as Lakes Appreciation Month in your state.

Most of all, remember to enjoy and appreciate these valuable freshwater resources.

Celebrate Lakes Appreciation Month!

From the Editor Bill Jones · issue should be an educator’s dream with the extremely strong group...

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