116 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



Table 29. — Weights of lake herring by sex and location taken in pound nets in southern Green Bay in 1949 



[Weight in ounces] 



of male and female lake herring of the spawning 

 run (October-November) in Saginaw Bay (all 

 lengths combined). Seasonal variations in differ- 

 ences of weight between the sexes in related species 

 have been reported by Jobes for Levcichthys 

 reighardi (1943), L. alpenae (1949a), and L. hoyi 

 (1949b) , and by Deason and Hile for L. kiyi (1947). 

 Comparisons by Bauch (1949) of the mean condi- 

 tion coefficients of Coregonus albnla of Mochelsee 

 showed that females were slightly heavier than 

 males during all seasons. In spawning-run 

 samples of the same species from Keitelesee 

 (Jarvi 1920) ripe females were heaviest for their 

 length and spent females were lightest (only 

 slightly lighter than males). 



ANNUAL DIFFERENCES IN WEIGHT 



Annual fluctuations in the length-weight relation 

 of Green Bay lake herring captured at the same 

 time of year (January or February) in 1949 to 1952 

 generally were small (table 30). Weights of fish 

 of the same length showed an upward trend from 

 1949 to 1952. The amount of change from year 

 to year is indicated roughly by the following 



Table 30. — Weights of lake herring taken in pound nets 

 during February 1949-51 and January 1952 



[Weight in ounces] 



