^QQ U. S. BUREAU OF FISHERIES 



A matliematical expression of the length-weight relationship in 

 terms of the formula y^ ax" lias been obtained for each of the three 

 species; namely, Sanger, yellow pike perch, and blue pike perch. The 

 weight of each species tends to increase approximately as the 3.15 

 poAver of the length. (A slightly different value was obtained for 

 each of the three species.) The' ''relative heaviness" or "state of 

 well-being" of the pike perches, as expressed by a coefficient of condi- 

 tions, K, obtained by the formula 



^ W.10-' 



xL = ^i^ 



has been found to vary with the length of the individual, with sex, 

 and according to the season of the year. No variation with respect 

 to locality was found. 



A history of the pike-perch fishery of Lake Erie has been com- 

 pleted. Sources include publications of various United States and 

 Canadian agencies as well as valuable unpublished records obtained 

 from certain commercial fishermen of Lake Erie. 



YELLOW PERCH 



Virtually all of the available data collected during the years 

 1927-32 on the age and growth of the yellow perch have been drawn 

 up in summary tables. The growth data (lengths and increments), 

 based largely on the measurements of scales, have been analyzed with 

 respect to age groups, year classes, sex, and localities. Age com- 

 position of the commercial catch has been ascertained with respect to 

 both seasonal fluctuations and locality. Individual weights of ap- 

 proximately 18,000 yellow perch have been tabulated by 5 millimeter 

 frequency intervals and have been subjected to analysis with respect 

 to type of gear, size of mesh, seasons, sex, sexual maturity, and 

 locality. Length frequencies were compiled to show variations with 

 respect to gear, seasons, and locality. The work on the yellow perch 

 was discontinued in June when F. W. Jobes was transferred to the 

 Washington office. 



CURRENT PROJECTS 



Current projects involve largely the writing of reports covering 

 the major investigations completed in the field. Such projects in- 

 clude the 5-year investigation on Lake Erie; the 2-year survey of 

 deep trap net operations on Lakes Huron and Michigan ; the three 

 seasons' work on the chub nets of Lake Michigan, including studies 

 on temperature and currents; and life histories of the whitefish of 

 Lakes Huron and Erie, the cisco of Lake Erie, the sheepshead of 

 Lake Erie, the chub of Lake Superior, and the herring of Lake 

 Huron. 



PACIFIC COAST AND ALASKA FISHERY INVESTIGATIONS 



Frederick A. Davidson, in charge 



The Pacific coast and Alaska fisliery investigations were confined 

 mainly to studies of the salmon fisheries in the Pacific Northwest 

 States and the salmon and herring fisheries of Alaska. The major 

 investigations of the salmon and herring fisheries conducted in these 



