FLUCTUATIONS IN THE POPULATION OF YELLOW PERCH, PERCA 

 FLAVESCENS (MITCHILL), IN SAGINAW BAY, LAKE HURON 



By Salah El-Din El-Zarka, University of Michigan! 



The yellow perch, Perca flavescens (Mitchill), 

 is one of the most important and widely distrib- 

 uted food fishes of the northeastern United States 

 and southeastern Canada. It inhabits the Great 

 Lakes, inland lakes, and large streams but is 

 never plentiful in Lake Superior. Because of 

 this wide distribution and its frequent great 

 abundance, the yellow perch has become impor- 

 tant to both commercial fishermen and anglers 

 in many localities. The commercial fishery sta- 

 tistics for 1954 from the United States and Can- 

 ada indicate that the yellow perch fishery con- 

 tributed 16,230,000 pounds or 13 percent of the 

 total production of the lake fisheries. It was 

 surpassed only by the lake herring which formed 

 18 percent of the total catch. In United States 

 waters of the Great Lakes, the yellow perch to- 

 gether with the chubs and lake herring formed 

 the largest percentage of the catch (lake herring 

 25.6 percent, chubs 13.5 percent, and yellow perch 

 10.0 percent). Statistics are not available on the 

 sport fishery of the Great Lakes, but it is well 

 known that in many localities the anglers annu- 

 ally remove more yellow perch than do the com- 

 mercial fishermen. Despite the wide range of the 

 species, the commercial production of yellow 

 perch is mostly concentrated in Lake Erie (espe- 

 cially the western part of the lake), Green Bay 

 in Lake Michigan, and Saginaw Bay in Lake 

 Huron. 



Few studies had been done on yellow perch in 

 the Great Lakes. Jobes (1952) published a de- 

 tailed account of the life history of yellow perch 

 in Lake Erie and Hile and Jobes (1942) issued 

 a small paper on the growth in Wisconsin waters 

 of Green Bay and northern Lake Michigan. In 



1 Present address Alexandria Institute of Hydroblology and 

 Fisheries, Kayet Bay, Alexandria, Egypt. 



Note. — Approved for publication October 23, 1957. Fishery 

 Bulletin 151. 



Saginaw Bay, a most important center of yellow 

 perch production in the State of Michigan, only 

 one small paper has been published (Hile and 

 Jobes 1941) reporting the age composition and 

 the growth rate of fish collected in 1929 and 1930. 



Since 1943 the annual visits to Saginaw Bay 

 by the United States Fish and Wildlife Service 

 employees indicated that the yellow perch popu- 

 lation was undergoing a definite change in its 

 size structure. The fish were much smaller than 

 in previous years and the percentage of legal- 

 sized fish (8i/ 2 inches) likewise was low. Thus, 

 because of the apparent threat to this valuable 

 fishery and hence to the economy of Saginaw Bay 

 commercial fishermen, it was decided to collect 

 materials that would permit the determination of 

 possible changes in the perch stocks since earlier 

 observations and would also throw light on vari- 

 ous aspects of the biology not previously ex- 

 plored. The collections of materials which were 

 started by the Fish and Wildlife Service staff 

 in 1943 formed the basis of the present study. 

 From these data it has been possible to describe 

 the general status of the population and follow 

 the changes in age composition, growth, and 

 other biological characters. 



This study of yellow perch in Saginaw Bay 

 was made possible by a cooperative arrangement 

 between the Department of Fisheries, School of 

 Natural Resources, University of Michigan, and 

 Great Lakes Fishery Investigations, Fish and 

 Wildlife Service, United States Department of 

 the Interior. I am grateful to Dr. Karl F. 

 Lagler, Chairman of the Department of Fisheries, 

 for recommending me to the Fish and Wildlife 

 Service and to Dr. James W. Moffett, Chief of 

 Great Lakes Fishery Investigations, for accept- 

 ing me temporarily in his research group. As 

 a de facto member of the Great Lakes staff I was 

 permitted the use of past collections of fish, given 



365 



