Size Structure of Female Yellow Perch Spawners as an Early Indicator of Year Class Strength

Yellow perch, Perca flavescens, in Lake Michigan have undergone severe fluctuations in abundance over the past three decades and recruitment has been increasingly erratic. Management of this valued sport fish is hampered by insufficient information about reproductive ecology and early life history traits. We examined temporal variation in spawning assemblage composition and fecundity with an attempt to investigate the role of female size on offspring characteristics. Adult yellow perch were collected at two historical spawning sites in southwestern Lake Michigan. Fish were measured, weighed and fecundity of gravid females was estimated. Moreover, a subset of ripe females was stripped of eggs, which were fertilized in the field, incubated and hatched to evaluate variation in size at hatch and oil globule volume. Spawning stock assessments indicated little temporal variation in annual relative abundance of female spawners; however, the size structure of female spawners varied among sample years. Fecundity of yellow perch increased exponentially with length and larger females typically produced bigger larvae with more energy reserves. Our results provide evidence that temporal changes in the size structure of female spawners can impact egg production, hatching success and ultimately recruitment success of yellow perch.