Modeling sources of variation for growth and predatory demand of Lake Erie walleye (Stizostedion vitreum), 1986-1995
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Date
1999
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Abstract
Given the variable nature of the Lake Erie ecosystem, we investigated biotic and abiotic sources of variation for walleye (Stizostedion vitreum) growth, consumption, and population-wide predatory demand. We
determined how temperature, population structure, and age-specific consumption influenced walleye growth and
consumption during 1986-1995. For each year, we used individual-based bioenergetics modeling to compare growth
and consumption by walleye in Lake Erie's western or central basin with those of walleye moving seasonally
between basins. Population structure strongly affected walleye growth and consumption but had little influence on
interbasin growth rate comparisons. Based on water temperature alone, growth and consumption by western basin
walleye were generally lower than for central basin or migratory populations and were more limited by summer
water temperatures. In simulations combining effects of population structure, temperature, and age-specific
consumption, migratory walleye grew most rapidly, taking advantage of temperature-related growth peaks in both
basins. Estimates of walleye predatory demand declined with population size from 1988 through 1995. With natural
feedbacks, predatory demand interacts with prey production, limiting walleye reproductive potential when prey
availability is low. However, immediate impact on predatory inertia is limited, complicating our ability to predict
how predatory demand and prey availability interact in Lake Erie.
Description
Abstract in English and French
Keywords
walleye growth, central basin (Lake Erie, OH), western basin (Lake Erie, OH), Lake Erie ecosystem
Citation
Kershner, Mark W.; Schael, Denise M.; Knight, Roger L.; Stein, Roy A.; Marschall, Elizabeth A. "Modeling sources of variation for growth and predatory demand of Lake Erie walleye (Stizostedion vitreum), 1986-1995," Canadian Journal of Fisheries and Aquatic Sciences, v. 56, no. 4, 1999, pp. 527-538.