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Effects of non-indigenous invertebrates on the pelagic food web of Lake Michigan
Primary Investigator:
Steven Pothoven
E-mail: steve.pothoven@noaa.gov
NOAA/GLERL
Co-Investigators:
Dr. Gary Fahnenstiel
E-mail: Gary.L.Fahnenstiel@noaa.gov
NOAA/GLERL
Dr. Henry Vanderploeg
E-mail: Henry.Vanderploeg@noaa.gov
NOAA/GLERL
Thomas Nalepa
E-mail: thomas.nalepa@noaa.gov
NOAA/GLERL
Executive summary
Our goal is to evaluate the status of the pelagic food web in Lake Michigan at sites where we also have access to historical data. This project encompasses four separate projects from other past and ongoing GLERL projects to help define the status and changes in the pelagic food web of Lake Michigan.
The pelagic food web is experiencing rapidly accelerated changes because of rapidly increasing abundances of quagga mussels in Lake Michigan. Quagga mussels (Dreissena bugensis ) were first found in Lake Michigan in 1997 (Nalepa et al. 2001) and by 2006 had become abundant in offshore areas of the lake. These mussels have replaced zebra mussels (Dreissena polymorpha ) in shallow areas, and are rapidly proliferating in colder, deeper areas where zebra mussels were not previously found.
In the Great Lakes, zebra mussels altered pelagic pathways in the near-shore and shifted productivity toward pathways of some bottom-dwelling (benthic) organisms (Fahnenstiel et al. 1995). In inshore rocky areas this has caused nuisance growth of Camphor. Because of the shift of nutrients and production in near-shore regions, offshore regions may experience a "near-shore phosphorus shunt." This shunt occurs when phosphorus does not reach offshore regions because it is contained in near-shore areas (Hecky et al. 2004).
It is also possible that mussels are directly having an effect offshore through their filtering, nutrient cycling, and engineering activities there. One of the most important engineering effects is increased water clarity caused by mussel removal of particles (Vanderploeg et al., 2002). In areas without rocky substrate such as the Muskegon area, such nuisance growths are not seen and impacts of mussels are seen farther offshore.
Several food web changes are related to the rapid proliferation of quagga mussels in Lake Huron between 2000-2003 including decreased zooplankton and fish production. During 2007 in southern Lake Michigan, numbers of phytoplankton, zooplankton, and Mysis relicta all appear reduced compared to historical data. Other invertebrate invasives may further impact lower food web components. For example, the mysid Hemimysis anomala, a new invasive species, was found in Lake Michigan in 2006 and could affect phytoplankton or zooplankton resources if it colonizes open water habitats in the lake. Bythotrephes longimanus and Cercopagis pengoi are two invasive cladocerans that could also alter zooplankton populations in the lake. Preliminary sampling indicates that spring pelagic phytoplankton abundance has decreased by more than 50% from the early 1990s. This decrease is primarily the result of the disappearance of classical spring bloom diatoms, which were an important food item for many lake invertebrates.
Proposed Work
This is a continuing project, beginning in January of 2008 with a tentative end date in December of 2009.
Current/Ongoing
- At Muskegon, sample at three sites biweekly (March thru December) for nutrients and phytoplankton, and monthly for benthos (quagga mussels), mussel veligers, zooplankton, and Mysis/Hemimysis
- At Grand Haven, collect data from two sites (nearshore and offshore), monthly (March thru December) for nutrients and phytoplankton in the spring (March-June)
- Evaluate the role of quagga mussel filtering and nutrient processing as drivers of offshore change in phytoplankton abundance with lab experiments
Four specific, individual projects are being conducted as part of this non-indigenous invertebrate study.
Project 1. Collect data on nutrients, chlorophyll, phytoplankton, and primary production at sites in the southern basin of Lake Michigan and use data to model primary productivity
- Goal: characterize primary producer communities within water column at sampling stations and the environmental variables driving primary producers
- Examine changes in plankton communities since arrival of the quagga mussel
- Sampling conducted bi-weekly to monthly (emphasis: spring isothermal sampling) at nearshore and offshore regions in Grand Haven and Muskegon
- Measure total phosphorus, particulate phosphorus, soluble phosphorus, particulate carbon, particulate nitrogen, soluble silica, nitrate, ammonia, phytoplankton abundance and biomass
- Photosynthesis-Energy curves to model water-column primary production constructed for each phytoplankton community with chlorophyll concentrations, surface and underwater irradiance measurements (Great Lakes Production Model)
Project 2. Evaluate status of pelagic crustaceans, including zooplankton, Mysis relicta, Bythotrephes longimanus, and Cercopagis pengoi, at sites in southern Lake Michigan to compare populations to historical data
- Goal: determine the abundance, population status (e.g. reproductive strategy and potential, growth), and consumption demands of each of these species at the sites sampled
Project 3. Evaluate status of quagga mussels including abundance, size structure, biomass, energy content, growth, and reproductive status in southern Lake Michigan
- Goal: monitor quagga mussel population in southern Lake Michigan and measure size-frequency and length-weight of quagga and zebra mussels at sites where water quality variables are being measured to provide estimation of biomass
- Compile life history of largely unknown profunda morph quagga mussels (dominant phenotype in Lake Michigan)
- Measure lipid content (long term energy storage), glycogen (short-term energy storage), RNA/DNA (growth), and gonadal development (reproductive status) of mussels on a monthly basis to measure "health" of population
- Measurements indicate if quagga mussel population will continue to increase, or decrease because of resource limitations
Project 4. Evaluate the role of quagga mussel filtering and nutrient processing as drivers of offshore change in phytoplankton abundance
- Goal: to define mussel temperature-feeding response by conducting seasonal feeding experiments (March-June and November and December) to capture isothermal and stratified conditions using methods of Vanderploeg et al. (2001)
- Filtering and feeding impacts will be projected to the whole of the southern basin from size-frequency and biomass information gathered in Project 3
- To help calculate impacts of mussels we will determine the relationship between mussel filter area and their lengths, since rates are most properly normalized to filter area.
Scientific rationale
Non-indigenous invertebrates are proliferating in Lake Michigan with potential large scale ecosystem changes for the food web. Most notably in the Great Lakes, declines of the benthic amphipod Diporeia are attributed the spread of dreissenid mussels (Nalepa et al. 2006). Diporeia spp. was the dominant benthic macroinvertebrate in the offshore waters of the Great Lakes (Nalepa 1989), and served as an important pathway between pelagic primary production and fish production in the Great Lakes. Diporeia depends on pelagic inputs of organic materials to the benthic region (Dermott and Corning 1988) and in turn, is eaten by most offshore fish species (Wells 1980).
The invasion by dreissenids and subsequent decline of Diporeia are associated with declines in condition, energy content, growth, and food consumption for the pelagic forage fish alewife Alosa pseudoharengus (Madenjian et al. 2003, Madenjian et al. 2006, Pothoven and Madenjian 2008). For the lake whitefish Coregonus clupeaformis, a benthic feeding fish that can consume dreissenids, condition and growth has also declined even though food consumption has not changed (Pothoven and Madenjian 2008). The declines in condition and growth are largely attributed to the low energy content of dreissends compared to previous prey such as Diporeia (Pothoven et al. 2001, Pothoven and Madenjian 2008).
Declines in Diporeia can increase predation pressure by fish on alternate prey such as Mysis or zooplankton. Additionally, predatory invasives such as Bythotrephes, Cercopagis, and Hemimysis can all compete with fish for zooplankton. Finally, system-wide decreases in primary production may limit production by higher trophic levels (e.g. zooplankton, Mysis) There is a clear need to understand the current status of these invasive predatory planktivores, as well as the status of prey such as Mysis or zooplankton that are critical for fish production.
Governmental/Societal Relevance
Following the severe decline of Diporeia in the Great Lakes, the importance of Mysis and zooplankton as food sources fishes has increased. Fishery managers are eager to understand the status of Mysis and zooplankton populations and their ability to support fish production in the Great Lakes. Fishery managers also want to understand how quagga mussels and other new invasive species are impacting primary productivity, zooplankton, and Mysis in offshore regions. Depending on how the food web is changing, fishery managers can adapt fish stocking and commercial harvest policies to help maintain healthy fish populations and sustainable levels of fishes in the Great Lakes. The results of this study will help managers understand whether quagga mussels populations are likely to continue to increase, or if populations of mussels are likely to decline due to resource limitations.
Relevance to Ecosystem Forecasting
By understanding how invasive species such as quagga mussels may have altered the offshore pelagic food and trophic linkages, we will be able to better predict the ability of systems with quagga mussels to produce healthy and sustainable fishery stocks. We anticipate that data collected and historical data will be used to predict energy flow to fish prey (zooplankton and Mysis) in offshore regions dominated by quagga mussels. Data will also be used to improve our understanding of how bottom-up forces regulate zooplankton and Mysis production. We will also predict mussel impacts on the food web as a function of mussel length frequency and biomass
Research Products
Publications:
Pothoven, S.A., I. A. Grigorovich, G. L. Fahnenstiel, M. D. Balcer. 2007. Introduction of the Ponto-Caspian bloody-red mysid Hemimysis anomala into the Lake Michigan basin. Journal of Great Lakes Research 33:285-292.
Presentations:
Pothoven, S. Lower food web changes and implications for the Lake Michigan fishery. Sea Grant regional fishery workshop, Grand Haven, MI, March 1, 2008
Pothoven, S. Status of bloody red shrimp and opossum shrimp in Lake Michigan. Sea Grant regional fishery workshop, Ludington, MI, January 5, 2008
Pothoven, S. The appearance of the bloody red shrimp in the Great Lakes. Lake Michigan Fishery Workshop-Sea Grant. Spring Lake MI, March, 3, 2007
Pothoven, S, Fahnenstiel, G, Grigorovich, I, Balcer, M. Appearance of Hemimysis anomala in the Great Lakes (poster). Great Lakes mini-workshop, The North American Great Lakes: Comparisons with the Baltic Sea. University of Michigan, Ann Arbor, MI. Feb. 20, 2007.
Pothoven, S. Hemimysis anomala: Observations from the Lake Michigan basin (1/11/07), GLERL seminar with live web cast.
Vanderploeg, H.A., Nalepa, T.F., Fahnenstiel, G.L., Pothoven, S.A., Liebig, J.R., Dyble, J. and Robinson, S. 2008. Dreissenids as nearshore and offshore engineers: predicting direct and indirect effects of mussels on pelagic food webs. 51st IAGLR Meeting, Peterborough, ON. May 19-23, 2008.
Cited References
Dermott, R., and K. Corning. 1988. Seasonal ingestion rates of Pontoporeia hoyi (Amphipoda) in Lake Ontario. Canadian Journal of Fisheries and Aquatic Sciences 45:1886-1895.
Fahnenstiel, G. L., Bridgeman, T. B., Lang, G. L., McCormick, M. J. & Nalepa, T. F. 1995. Phytoplankton productivity in Saginaw Bay, Lake Huron: effects of zebra mussel (Dreissena polymorpha). Journal of Great Lakes Research 21, 465-475.
Hecky, R. E., R. E. H. Smith, D. R. Barton, S. J. Guildford, W. D. Taylor, M. N. Charlton, and T. Howell. 2004. The nearshore phosphorus shunt: a consequence of ecosystem engineering by dreissenids in the Laurentian Great Lakes. Canadian Journal of Fisheries and Aquatic Sciences 61:1285-1293.
Madenjian, C. P., S. A. Pothoven, J. M. Dettmers, and J. D. Holuszko. 2006. Changes in seasonal energy density of alewife (Alosa pseudoharengus ) in Lake Michigan after invasion of dreissenid mussels. Canadian Journal of Fisheries and Aquatic Sciences 63:1-12.
Madenjian, C. P., J. D. Holuszko, and T. J. DeSorcie. 2003. Growth and condition of alewives in Lake Michigan, 1984-2001. Transactions of the American Fisheries Society 132:1104-1116.
Nalepa, T. F., D. L. Fanslow, A. J. Foley, G. A. Lang, B. J. Eadie, and M. A. Quigley. 2006. Continued disappearance of the benthic amphipod Diporeia spp . in Lake Michigan: is there evidence for food limitation? Canadian Journal of Fisheries and Aquatic Sciences 63:872-890.
Nalepa, T. F., Schloesser, D. W., Pothoven, S. A., Hondorp, D. W., Fanslow, D. L., Tuchman, M. L., and Fleischer, G. W. 2001. First finding of the amphipod Echinogammarus ischnus and the mussel Dreissena bugensis in Lake Michigan. Journal of Great Lakes Research 27(3):384-391.
Nalepa, T. F. 1989. Estimates of macroinvertebrate biomass in Lake Michigan. Journal of Great Lakes Research 15:437-443.
Pothoven, S. and Madenjian, C. 2008. Alewife and lake whitefish: changes in consumption following dreissenid invasions in Lakes Michigan and Huron. North American Journal of Fisheries Management 28:308-320.
Pothoven, S. A., T. F. Nalepa, P. J. Schneeberger, and S. B. Brandt. 2001. Changes in diet and body condition of lake whitefish in southern Lake Michigan associated with changes in benthos. North American Journal of Fisheries Management 21:876 - 883.
Vanderploeg, H. A., T. F. Nalepa, D. J. Jude, E. L. Mills, K. T. Holbeck, J. R. Liebig, I. A. Grigorovich, and H. Ojaveer, 2002. Dispersal and emerging ecological impacts of Ponto-Caspian species in the Laurentian Great Lakes. Canadian Journal of Fisheries and Aquatic Sciences 59:1209-1228.
Wells, L. 1980. Food of alewives, yellow perch, spottail shiners, trout-perch, and slimy and fourhorn sculpins in southeastern Lake Michigan. U. S. Fish and Wildlife Service Fishery Bulletin 67:1-15.
Last updated: 2008-06-06 mbl