Michigan Department of Natural Resources
Fisheries Research Report No.1864, 1979
Fish Predation on Lake Trout Eggs and Fry in the Great Lakes, 1973 - 1978
Thomas M. Stauffer and Wilbert C. Wagner
Abstract.-During lake trout spawning predation on eggs was very light. Round whitefish (745) and burbot (20) contained 1 and 29 lake trout eggs per fish, respectively, but there was less than 0. 1 egg per stomach in lake trout (821), longnose suckers (456), lake chubs (103), white suckers (37), and lake whitefish (24). The apparent scarcity of fish other than lake trout in multisized mesh gill nets at spawning time also suggested that predation was light. Sculpins ate a few eggs in the 1- to 3-week period after lake trout spawning. In contrast to predation on naturally deposited eggs, predation on artificially deposited eggs was severe, at least during the 24-hour period after deposition. In these collections lake trout (8) contained 515 eggs per fish, round whitefish (41) 44, and longnose suckers (9) 16. Alewives (49) did not contain eggs.
Predation on fry was practically nil while they were on a spawning reef and while they migrated away from the reef during May-July. Although burbot (97) contained 0.2 fry per stomach, the number of fry per stomach was less as than 0.02 for mottled sculpins (796), slimy Sculpins (669), yellow perch (188), round whitefish (110), trout-perch (106), coho salmon (65), and rainbow smelt (49).