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Rapid changes in age and size at maturity in Lake Erie yellow perch (Perca flavescens) are not explained by harvest

Gíslason, Davíð, McLaughlin, Robert L., Robinson, Beren W., Cook, Andy, Dunlop, Erin S.
Canadian journal of fisheries and aquatic sciences 2018 v.75 no.2 pp. 211-223
Perca flavescens, ecosystems, freshwater fish, harvesting, juveniles, life history, models, phenotype, phenotypic plasticity, Lake Erie
Harvest can change phenotypic traits of populations through immediate demographic consequences, evolutionary responses to harvest selection, or developmental responses by individuals. This study investigated the plastic phenotypic effects of harvest on size and age at maturity in a commercially exploited freshwater fish. We tested an individual growth and life history plasticity model using lagged correlations incorporating how harvesting fish ages 2 and older influenced the abundance of juvenile fish, resource availability, individual growth rates, and carry-over responses in age and size at maturity. Our test used cohort data for Lake Erie yellow perch (Perca flavescens). Age and size at maturity fluctuated widely and rapidly across 23 cohorts between 1991 and 2013, suggesting phenotypic plasticity contributed strongly to maturation dynamics. The changes in maturity could not be explained by responses to harvest, as expected under the plasticity model. In Lake Erie, age and size at maturity in yellow perch appear to be responding to other drivers, such as harvest-induced dynamics of other fish stocks or ecosystem changes that are independent of harvest.