200 Shelby D. Gerking 



compute the rate of increase in body weight with length. 

 Here he found the relationship to he W = 0-0044 L^'^^ based 

 on the mean yearly weights as recorded by Russell. At all 

 ages fecundity increased more rapidly than body weight. 



The relationship between fecundity and body weight was: 

 F = 196 X PF^'^* (all ages). Since the exponent is greater 

 than one, the equation confirmed the above interpretation 

 that fecundity increases at a rate greater than body weight. 

 The rate of increase in ovary weight with length was consistent 

 with this result. The rate of decline in body weight with 

 length during ovarian development showed that somatic 

 tissue was being converted to gonad from November to June, 

 the spawning season, and that somatic tissue increased from 

 July to November. 



The consistency of Raitt's results arouses serious suspicion 

 that reproduction is a drain on the individual in later life. In 

 his words, "One cannot but regard the above evidence as 

 hinting at an end point to reproduction, and inviting postula- 

 tion of stress of egg production, ultimately overbalancing 

 ability to recover within the annual cycle. It would seem that 

 an affirmative answer is suggested to Orton's question of 

 whether 'over-reproduction' may be regarded as a general 

 predisposing cause of death in fishes." 



Long rough dab. Bagenal (1957a) has recently studied 

 the fecundity of the long rough dab of Scotland by detailed 

 statistical procedures. His fish were caught in one locality by 

 a small mesh cotton trawl. Length, sex, gutted weight, gonad 

 weight, and age were determined for a large series of specimens 

 taken from October 1933 to May 1955. Egg counts and the 

 foregoing measurements were made on two samples, totalling 

 119 females, one caught in February and the other in March 

 1954, just before spawning. By an analysis of covariance he 

 was able to show that there was no effect of age on the length/ 

 weight regression so all ages were pooled for the calculation of 

 the regression coefficient describing this relationship. Simil- 

 arly, age had no significant effect on the ovary weight/body 



