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MODELING THE RESPONSE OF FISH POPULATIONS TO EUTROPHICATION
Citation:
Rashleigh, B AND D. J. Randall. MODELING THE RESPONSE OF FISH POPULATIONS TO EUTROPHICATION. Presented at Ecological Society of America Annual Meeting, Savannah, GA, August 3-8, 2003.
Impact/Purpose:
Improve the scientific understanding of the processes controlling nutrient distributions in surface waters. Produce a suite of enhanced models for characterizing nutrient distributions in surface waters by incorporating improved process understanding in existing models (e.g., WASP), by developing new models (e.g., WHAM, reactive transport), and improving linkages between model components.
Description:
Eutrophication resulting from nonpoint source pollution is one of the largest environmental problems in lakes and reservoirs around the world. Two characteristics of eutrophication, decreased dissolved oxygen and increased concentration of ammonia, are known to affect fishes, yet models of eutrophication rarely include fishes. We developed a model to quantify population-level effects of eutrophication on fish. The model uses oxygen, ammonia, pH, and temperature outputs from a water quality model as driving variables and incorporates results from individual-level fish toxicology studies of growth, survival, and reproduction conducted in the laboratory. The model is applied to Lake Peipsi in Estonia/Russia. We focus on two common, commercially-important fish species, smelt (prey) and pikeperch (predator). Results indicate that the two fish species respond similarly to eutrophication, the fish populations are most sensitive to changes in oxygen, and over time, ammonia and oxygen changes are synergistic in their effects on populations. This model can be used to assess the response of the fisheries to future water quality scenarios and restoration activities.