younger fish, mainly 2 and 3 years of age, 

 should show sharper fluctuations than one 

 depending on several age groups of older 

 fish. Since each brood of young scup is sepa- 

 rated by size differences, changes in the 

 amount of each brood by varying success 

 of reproduction is quickly reflected in the 

 catch that depends mainly only on one or two 

 young age groups. Such is the case in New 

 Jersey. On the other hand, in the case of a 

 fishery depending on older and larger fish 

 (New York to southern New England), the 

 broods are less distinctly separated from 

 each other by size difference, and the annual 

 Increments are relatively less than in the case 

 of younger broods because of the mortality 

 from long exploitation and natural causes. 

 Hence, the catch remains more nearly con- 

 stant and reflects changes only when they 

 attain major importance. Therefore, although 

 the pound net and trap fisheries of New York 

 and Rhode Island experienced an increase in 

 yield simultaneously with that of New Jersey 

 because of the entrance of large broods of 

 young scup, these younger fish were less 

 conspicuous in the presence of larger and 

 older fish in greater numbers. 



It can also be seen that the catch per trap 

 in the fishery in southern New Jersey did not 

 fluctuate in the same manner as that in 



northern New Jersey (fig. 4). This would 

 indicate that the fisheries of the two areas 

 catch different populations of scup. This situa- 

 tion is not clear since samples of scup in the 

 two areas show that broods of the same year 

 appeared in both areas. It is possible that 

 the same broods are found in both areas but 

 in different abundance. 



Moreover, the practices of pounding scup 

 and sifting out small fish tend to diminish 

 the apparent importance of the younger fish 

 in the catch and to reduce the amount of 

 reported catch. The extent of this practice 

 from year to year, depending on the runs 

 of fish and economic conditions, naturally 

 affects fluctuations based on the catch rec- 

 ords. This also may explain why certain 

 broods of younger and smaller fish, which 

 comprised the bulk of the catch of New Jersey 

 pound net fishery in certain recent years, 

 were relatively less reliable measures of 

 fluctuation than the catch of the New York- 

 Rhode Island fishery in the same seasons. 



From this discussion it is suggested that, 

 although the data on the scup fishery of 

 New York-Rhode Island are subjected to much 

 inaccuracy because of the practices of the 

 fishery and for which sufficient correction 

 cannot be made, they do nevertheless reflect 

 major changes in the catch. 



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