The Ontogeny of Yellow Perch Recruitment

Recruitment of yellow perch Perca flavescens has been of importance to fisheries biologists due to their ecological value as prey for other species of fish and economic importance as a highly sought sportfish.  Yellow perch recruitment is often highly variable in many systems and is typified by strong, weak, or even missing year classes.  Much research has been devoted to understanding specific mechanisms regulating recruitment of this species; research has often focused specifically on one or two life stages at one time (e.g., eggs and larvae, larvae and juveniles) but rarely accounting for multiple different factors that can affect survival across the ontogeny of life for this species.  Our current understanding of yellow perch recruitment identifies the importance of both abiotic and biotic factors, but the level of influence (e.g., weak, strong) may depend on the life stage examined.  Using existing studies we developed three working hypotheses to examine yellow perch recruitment patterns at two larval life stages (5-14 d old, 15-24 d old) and to further identify overarching mechanisms (abiotic vs. biotic) related to yellow perch recruitment in Pelican Lake, Nebraska, during 2004 to 2012.  Larval yellow perch growth and mortality were largely regulated by hatching date, temperature, and zooplankton availability.  Young (5-14 d old – daily otolith age estimation) larval yellow perch growth was positively related to temperature and hatch date; old (15-24 d old) larval yellow perch growth was positively related to water temperature and age-0 yellow perch densities, but negatively related to available preferred zooplankton.  Mortality was inversely related to total zooplankton biomass and positively related to water temperature.  Our results support utilizing a generalized framework that incorporates an array of biotic and abiotic factors during multiple life stages to better understand yellow perch recruitment.