238 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



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TOTAL LENGTH IN INCHES 



Figure 8. — Percentage frequency distribution of total length of Lake Erie yellow perch in 1927, 1928, and 1929 collections 

 from impounding nets. Curves extend only over length range where representation was continuous. 



be explained by the known age composition of the 

 stock and the time of year when the collections 

 were obtained . A similar explanation may acco unt 

 for the shifts in the modal frequency of the years 

 1930 to 1932 and 1937. 



The gill-net collections showed trends in the 

 annual fluctuation of the length at maximum 

 abundance similar to those of the impoimding nets, 

 but the total range of variation of the length of the 

 modal frequencies of the fish actually gUled was 



reduced. The modal frequency interval of the 

 shoal-net samples varied only from 201-210 mm. 

 (9.4 mches total length) in 1928 and 1929 to 

 211-220 mm. (9.9 mches total length) in 1927, 

 or extended over a range of 10 mm. as compared 

 with a range of 30 mm. in impounding-net samples. 

 The modes of the yellow perch actually gilled by 

 the bull net were at the 201-210 mm. (9.4 inches 

 total length) interval in 1927 and 1928, and at the 

 211-220 mm. (9.9 inches total length) level in 



