The effects of life history parameters on the reproductive potential of yellow perch (Perca flavescens) populations

grantor: University of TorontoYellow perch populations in Lake Erie exhibit large yearly fluctuations in year class strength (YCS), with most years showing relatively poor recruitment. For percids, no statistically significant relationship between stock and recruitment has been found. Most research has focussed on various environmental factors to explain the variability in YCS. Of the studies reviewed in the first chapter, variations in YCS could not be explained by variation in any single environmental factor. The second chapter revisited the theoretical equation that spawning stock size is related to recruitment. Yearly variation in the number of mature females in the spawning stock may explain the variability in the YCS of perch. We found that the proportion of fish at age varied annually from 1978-1990, suggesting that intermittent reproduction exists for Lake Erie yellow perch. The third chapter evaluated through a model whether variation in the proportion mature as well as interannual variations in age distributions, size and the associated size-related fecundity could explain the variability in YCS of the yellow perch populations. Variation in the proportion mature could explain a large proportion of the observed YCS, however we could not accurately predict recruitment from the variations in the life history parameters included in the model.M.Sc