Relationship between Year‐Class Strength for Goldeyes and Selected Environmental Variables during the First Year of Life

I investigated the relationships between year‐class strength and selected environmental variables for the migratory population of goldeye Hiodon alosoides of the Peace–Athabasca delta, Alberta, Canada. Year‐class strength was highly variable from year to year. Goldeyes from the 1971 year‐class dominated the catch (up to 87%) in the 1970s, and other dominant year‐classes (>25% of the catch) developed in 1982 and 1989. The 1985 year‐class failed completely. On average, dominant or abundant year‐classes (>5% of the catch) occurred about three times per decade. Year‐class strength was related to the number of warm days (mean daily temperature >15°C) from May 1 to July 31, the period that covers the time from the spawning migration to the development of a 57‐mm, 1.9‐g juvenile goldeye ( r = 0.57, P < 0.01). The semibuoyant eggs and larvae of goldeyes were present in the delta primarily from May 22 to June 20. A linear relationship was not evident between year‐class strength and wind intensity during this 30‐d period ( r = −0.09). However, dominant and abundant year‐classes usually developed in those years when this 30‐d period was both warm and calm (wind intensity usually <20 km/h during the day). Year‐class strength was not related to discharge of the Peace River, the winter habitat of goldeyes, or to water levels in Mamawi and Claire lakes, the spawning and rearing habitats. Density‐independent mechanisms regulate recruitment in the Peace–Athabasca delta population of goldeyes.