Chapter 16: Walleye and Yellow Perch in Oneida Lake
Lars G. Rudstam, James R. Jackson, Anthony J. VanDeValk, Thomas E. Brooking, William W. Fetzer, Brian J. Irwin, and John L. Forney
The number of fish of a given year-class that survive to maturity is highly variable both in marine and freshwater systems. Understanding the causes and consequences of this variability has been a goal of fisheries science for more than a century (Hjort 1914; Sissenwine 1984; Cowan and Shaw 2002; Houde 2008). Much of this variability is due to processes operating during the first year of life, including abiotic factors such as temperature, wind, and ice cover, as well as biotic factors such as food quantity and quality, predation, competition, and egg quality. Scientists have devoted significant effort towards understanding the importance of these factors because fish recruitment variability has consequences to fisheries, to population viability, and to ecosystem function. If future recruitment is predictable, so are future fisheries yields and therefore the potential future economic returns from the fishery. Additionally, management will be better informed about future stocks, allowing for more proactive adjustment of harvest regulations aimed at maintaining desired population sizes and catch rates. Fish also affect ecosystems in a variety of ways (Carpenter and Kitchell 1984; McQueen et al. 1986; Vanni et al. 2005), and the effects of strong year classes can be observed over decadal time scales (Rudstam et al. 1993). Thus, predicting future year-class strength is important both for economic and ecological forecasting.