Factors related to growth and survival of larval walleyes: implications for recruitment in a southern Great Plains reservoir

Abstract

Larval fishes, limnological characteristics, and zooplankton populations were sampled from Glen Elder Reservoir, Kansas, during 1999–2001 to determine factors associated with growth and survival of larval walleyes ( Stizostedion vitreum). Ichthyoplankton populations were sampled weekly from April to June during all years using paired conical nets. Water temperature and zooplankton populations were sampled at each ichthyoplankton sampling site. Approximately, 70% of all larval fishes and 80% of the larval walleyes were sampled in the upper reservoir during all years. Cyprinidae and Centrarchidae were the only taxa that were more abundant in the main reservoir than the upper reservoir. Despite similarities in zooplankton abundance between years, recruitment of walleyes in 1999 was the lowest in nearly 20 years, while moderate year classes were produced in 2000 and 2001. During 1999, low, variable spring temperatures resulted in poor growth of larval walleyes. Poor growth of walleyes, coupled with high densities of larval gizzard shad ( Dorosoma cepedianum), resulted in poor recruitment during 1999. Walleyes grew faster in 2000 and 2001 and were able to consume larval gizzard shad resulting in moderate recruitment. These results suggest that abiotic conditions mediate biotic interactions and that both abiotic and biotic characteristics are important for regulating walleye recruitment dynamics.