Factors Influencing the Year-Class Stength of Reef Spawned Walleye in Western211 Lake Erie

摘要

Variation in egg and larval survival have been suspected to be principal sources211u001eof walleye Stizostedion vitreum recruitment variability in Lake Erie. I examined 211u001ewalleye egg deposition and survival and larval vital rates in western Lake Erie 211u001ein 1994 and 1995. Densities of eggs and larvae were higher in 1994 than 1995. 211u001eGrowth of larval walleye was greater in 1994. Larval densities were greater at 211u001ewestern sites in 1994 and greater at eastern and south-eastern sites in 1995. 211u001eSlow water warming rates and frequent intense winds contributed to the low 211u001edensity and survival of eggs on reefs in 1995 by prolonging incubation periods 211u001eand increasing the vulnerability of eggs to mortality factors. Optimal year-class 211u001estrength could result with precisely timed events providing high egg densities, 211u001efast water warming rates and few wind storms in spring providing good egg 211u001esurvival and high larval densities.