Kootenai River white sturgeon spawning migration behaviour and a predictive model
migration, spawning, sturgeon, adult, telemetry, environmental conditions, environmental variables, regression, water management, efficiency
Journal or Book Title
North American Journal of Fisheries Management
Each autumn and spring, adult white sturgeon (Acipenser transmontanus) migrate fromthe lower Kootenai River and Kootenay Lake, British Columbia, to prespawn staging reaches inIdaho. In spring, they migrate further upriver to a spawning reach near Bonners Ferry, Idaho. Wemonitored movement and behaviour of 49 reproductively mature white sturgeon with radio andsonic telemetry from 1991 through 1997. White sturgeon responded to mitigated flows from 1994through 1997, migrating substantial distances to a spawning reach soon after the onset of localrunoff and rising water temperatures. Males migrated at temperatures of 5.5-12.1degreesC, 2weeks before spawning; females followed about a week later, at slightly warmer temperatures.Females stayed in the spawning reach 1-28 d, averaging 10.5 d. Males spent 7 d to 2 months inthe spawning reach, averaging 30 d. After spawning, 63% of the females moved immediately toKootenay Lake; the remainder spent a longer time in the river downstream of the spawning reach.Some (52%) males remained in the river, and the remainder migrated to Kootenay Lake. Femalebehaviour and migration was more attuned to environmental conditions than was male behaviour.Several environmental variables were examined to determine their effect on female whitesturgeon migration to the spawning reach. Changes in temperature and river stage were the bestpredictors of the probability that females would migrate to the spawning reach. A logisticregression model, when applied to a subset of our original observations, correctly predictedmovement to the spawning area 93% of the time. Our model can be used as a tool for riskassessment of white sturgeon spawning migration during various snow pack or temperatureforecasts. It will be helpful in determining approximate migration or spawning times, making watermanagement decisions, and assessing effects of temperature fluctuations. The model will beuseful to continued study of white sturgeon by predicting spawning migration and improvingefficiency in deploying sampling gear.