196 



Shelby D. Gerking 



of the weight of the gonad and egg number as related to age. 

 The rate of increase in gonad weight with respect to age was 

 greater than the rate of increase in egg number. Therefore 

 Hickhng was forced to conclude that the permanent tissue of 

 the ovary increases disproportionately as the herring grows 

 larger and older. This suggests a gradual degeneration of the 

 ovary, the reproductive tissues being replaced by connective 

 tissue in much the same manner as the testis changes in 

 Astyanax mexicanus in relation to age (Rasquin and Hafter, 

 1951). Unfortunately, there have been no observations of this 

 sort on the histology of the fish ovary. 



Table II 



Regressions of body weight in grams (TF), gonad weight in grams 



(GW), AND fecundity {F) on body length in centimetres (L) in the 



ENGLISH HERRING {Clupca harengus). Taken from Hickling (1940) 



Research on the fecundity of the Pacific herring (Clupea 

 pallasii) agrees with the conclusions of Hickling and Farran. 

 Katz and Erickson (1950) analysed the relationship of 

 fecundity and length in different age groups. This is a log-log 

 relation described by the formula: F = CL^, where F = 

 fecundity, L = length, and C and n are empirically deter- 

 mined constants. The values of the exponent differed con- 

 siderably among separate age groups. Those herring that 

 were spawning for the first time (age II) were the least effec- 

 tive egg producers {n = 3-46). Age groups III and IV were 

 most efficient (n =3-89 and 3-87, respectively). The rate of 

 increase in fecundity was considerably less among ages V to 

 VIII (n =3-52). This result suggests that the relation of 



