Effects of Temperature, Discharge, and Weather on Walleye Spawning Movements in Tributaries of Lakes Erie and Huron

Walleye support a multi-billion dollar fishery on the Great Lakes. A large-scale acoustic telemetry study was conducted in lakes Erie and Huron to better understand movement patterns within and between lakes and provide critical information to support management. Detection data were used to identify environmental and biological characteristics associated with the timing and extent of walleye movement from riverine spawning grounds into the lakes and back again. Spawning walleye in the Tittabawassee River, Michigan and the Maumee River, Ohio were implanted with acoustic transmitters during 2011-2012 and their movements during subsequent spawning seasons were monitored. Zero-inflated Poisson models were used to test effects of environmental conditions and biological characteristics on pre- and post-spawning walleye movements. A model including sex, Julian day, water temperature, and river discharge accounted for the greatest percentage of variation in fish movements into rivers during the spawning period. Males arrived prior to females and stay in the river longer than females. Once in the river, movement onto the spawning shoal was most influenced by water temperature and Julian day. Knowing precise timing of male and female spawning movements will allow management regulations to protect that portion of the run when females are especially vulnerable.