Old tales in recent context: Current perspective on yellow perch recruitment in Lake Michigan

To evaluate factors affecting recruitment of yellow perch Perca flavescens in southwestern Lake Michigan, a Ricker stock-recruitment model was fitted to age-0 abundance estimated from a fall bottom trawl survey (1989-2007) and spawning stock biomass estimates. Models were built for all possible combinations of four external variables: spring-summer water temperature, June nearshore zooplankton density, spring abundance of alewives Alosa pseudoharengus, and an index of wind-induced transport of yellow perch larvae. Four relatively parsimonious models were deemed robust, and three external variables were represented (spring-summer water temperature, spring alewife abundance, and June zooplankton density). The Ricker stock-recruitment model with the lowest value of Akaike's information criterion (i.e., the best-supported model) included spring-summer water temperature and spring alewife abundance. The basic Ricker stock-recruitment model ranked second, followed by the Ricker model that included June zooplankton density. The fourth Rickermodel that was deemed robust included spring-summer water temperature. The four best models provided a good fit to age-0 yellow perch abundance estimates based on fall seining catches along the Illinois shoreline of Lake Michigan during 1989-2007. Our findings indicate that over the last two decades, yellow perch recruitment benefited during years associated with relatively warm water, low alewife abundance, and high zooplankton density.