PARENT SESSION
Oral Session 80: Fish Ecology III: Streams and Lakes.
Presiding: M Scheuerell and M Savacool Zimmerman
Wednesday, August 4, 1:30 PM to 5:00 PM, Meeting Room B 117.
Variation in growth and life history of walleye (Stizostedion vitreum) in Lake Erie habitats.
Wang, Hui-Yu*,1, Rutherford, Edward2, Cook, Andy3, 1 Department of Fisheries and Wildlife, East Lansing, MI, USA2 School of Natural Resources and Environment, Ann Arbor, MI, USA3 Ontario Ministry of Natural Resources, Wheatley, Ontario, Canada
ABSTRACT- Walleye (Stizostedion vitreum) is an important predator in Great Lakes ecosystems and supports valuable sport and commercial fisheries. In Lake Erie, walleye growth, survival and age at first maturity varies among areas that differ in depth, productivity and temperature, potentially influencing population stability and management. We investigated the mechanisms linking growth and life history traits of walleye to Lake Erie habitats using fishery biological data from OMNR experimental gillnet fall surveys (1991-2001). Although walleye juvenile growth rate was highest in western basin, mean adult size was largest in the central and eastern basins. Walleye matured earlier and at smaller sizes in central and eastern basins than in western basin. Adult walleye growth rate was highest in central and eastern basins, and was correlated with lower water temperature and high forage fish biomass there. Walleye population density was highest in western basin, possibly decreasing adult growth rate through increased intra-specific competition. Natural mortality rate was highest in western basin and lowest in eastern basin, and varied inversely with adult growth rate and longevity but positively with age at first maturity. The observed shape of reaction norm of walleye age and size at maturity was correlated with the estimated natural mortality pattern; adult, and potentially juvenile mortality rate, increased with growth rate decrease. Results of this study provide critical knowledge for management of Lake Erie walleye fisheries, and emphasize the need to monitor fisheries on a whole-lake scale.
Key words: Life history, Walleye