FOOD OF YOUNG-OF-THE-YEAR WALLEYES IN LAKE ERIE 



By David R. Wolfert, Fishery Biologist (Research) 



Bureau of Commercial Fisheries Biological Laboratory 



Ann Arbor, Mich. 



ABSTRACT 



Stomach contents were examined for 794 young-of- 

 the-year (O-group) walleyes (Stizostedion vitreum 

 vitreum) captured by trawls at 17 locations in western 

 Lake Erie in June-November 1962. Food organisms 

 were found in 92.5 percent of the stomachs. Food 

 varied with geographic location and season of capture, 

 but within areas and seasons, selection for certain 

 species and sizes of prey was strong. Walleyes from the 

 extreme western end of Lake Erie fed primarily on 

 gizzard shad and alewives during the summer and 



shifted to emerald shiners during the fall. The stomach 

 contents of walleyes from the Island region changed 

 from mainly yellow perch during the summer to emerald 

 shiners by the end of the year. Walleyes collected east 

 of the Islands had consumed only smelt and yellow 

 perch. The numbers of forage species caught with 

 walleyes in trawls showed little correlation with the 

 representation of these species in walleye stomachs. 

 Walleyes fed on the smallest individuals of each species 

 regardless of species preferences. 



Among the fishes of primary economic im- 

 portance in Lake Erie, the cisco or lake herring 

 (Coregonus artedi) , the whitefish (C. clupeaformis) , 

 the sauger (Stizostedion canadense) , and the blue 

 pike (S. vitreum glaucum) have become commercial- 

 ly unimportant, mostly in recent years. The last 

 remaining "high-priced" fish left to the industry — 

 the walleye (S. vitreum vitreum) — has also declined 

 to a remnant population which fluctuates widely 

 in abundance. The commercial catch (United 

 States and Canadian) of walleyes has declined 

 from a peak of 15,405,000 pounds in 1956 to a 

 low of 717,000 pounds in 1962. The decline has 

 been accompanied by demands for management 

 of the fishery to restore and maintain abundance. 

 Recent studies of the life history of the walleye 

 were begun in 1957 to provide information 

 essential to management. This report on feeding 

 of young-of-the-year (O-group) walleyes at var- 



Note.— Approved for publication Oct. 14, 1964. 



This research was completed at the Biological Field Station, Sandusky, 

 Ohio. 



ious seasons of the year and at different loca- 

 tions in western Lake Erie is a contribution to 

 these studies. 



MATERIALS AND METHODS 



The contents were examined of 794 stomachs 

 from O-group walleyes of the 1962 year class col- 

 lected in western Lake Erie at 17 locations in 

 June-November 1962 (fig. 1). All collections 

 were from U.S. waters and were made during 

 routine trawling to ascertain the relative success 

 of the hatching and survival of commercial and 

 other species. The fish were caught in semi- 

 balloon bottom trawls by Bureau of Commercial 

 Fisheries vessels, Musky II (523 fish), Kaho (35), 

 and an outboard-motor boat (233), and the Ohio 

 Division of Wildlife vessel Explorer (3) . The wall- 

 eyes were preserved whole in 20 percent formalin 

 after then- abdomens had been slit; examinations 

 and measurements were made in the laboratory. 

 Food organisms were identified to the lowest 

 taxonomic level possible. Stomach contents 



FISHERY BULLETIN: VOLUME 65, NO. 2 



489 



