Spawning and Larva Drift of Sympatric Walleyes and White Suckers in an Ontario Stream

Abstract

Walleyes Stizostedion vitreum vitreum and white suckers Catostomus commersoni shared a common spawning ground in Apsley Creek. Their reproduction overlapped in time, but white suckers spawned mainly in the riffle zone (710 eggs/m2) and rarely in quiet water (0.5 eggs/m2) surrounding the riffle. In contrast, walleyes spawned more in quiet water (6,241 eggs/m2) than in the riffle (65 eggs/m2). Walleye egg survival was higher on a sand-gravel-rock substrate than it was on a mud-detritus bottom. Spottail shiners Notropis hudsonius and yellow perch Perca flavescens fed extensively on walleye eggs; predation on white sucker eggs was not detected. Larva drift of both species was passive, varying with stream velocity, and occurred during periods of decreasing light (2100–0100 hours). Although eggs of both species began hatching on May 7, white sucker larvae drifted 11–13 d after walleye larvae. There was no indication that walleyes and white suckers competed for spawning areas as adults or for food as larvae.