Migration and Spatial Ecology of Walleye: Linkages Between a Nearshore Predator and Offshore Prey

Session: 54. - Food Web Ecology and Dynamics of Lake Ontario: Nearshore ? Pelagic Linkages

Erin Brown, Ontario Ministry of Natural Resources and Forestry, [email protected]
Jim Hoyle, ON Ministry of Natural Resources, [email protected]

Abstract

Walleye (Sander vitreum) are the dominant piscivorous fish in the Bay of Quinte - eastern Lake Ontario nearshore waters and are known to be highly migratory. Historical mark-recapture studies and age-specific geographical and seasonal distributions suggest movements are related to spawning habitat, temperature regimes, and foraging opportunities. Acoustic telemetry techniques were used to describe walleye movement at a finer scale than currently exists, and subsequently, to better understand the mechanisms which influence aspects of walleye life history. We explore the hypothesis that walleye movements from the Bay of Quinte to eastern Lake Ontario during the late-spring and early summer are associated with seasonal offshore pelagic prey dynamics, and that this predator-prey interaction is related to improved fitness. We present seasonal distribution and movement patterns of mature walleye, identify areas of walleye aggregation, and describe a period of distributional overlap of an offshore prey, alewife (Alosa pseudoharengus), in eastern Lake Ontario. An analysis of diet and condition reveals a positive relationship between large walleye condition, and alewife condition and availability. This work highlights linkages which exist between the condition and abundance of seasonally available offshore prey, and the condition and migratory patterns of walleye.

1. Keyword
walleye

2. Keyword
alewife

3. Keyword
Lake Ontario