Table 6. Length frequent-ien of ccup In random samples from catch by pound nets in the vicinity of Long Branch, N, J., lOPA-M 



[Numbcn of risli] 



age determination was applied to all data from 

 all localities throughout the period of investi- 

 gation. Growth data were derived for each 

 year class from 1927 to 1931. Using this 

 information, we determined that the scup of 

 certain ages reach the average modal lengths 

 listed in table 8. Length- weight and age curve 

 for scup is shown in figure 7. 



By this length frequency method, it was also 

 possible to determine the approximate com- 

 position of the catch in terms of the age of 

 the fish and to compare the relative impor- 

 tance of the broods that composed the catch. 



The fishery at Long Branch is representa- 

 tive of the general inshore New Jersey pound 

 net fishery and has, therefore, been used to 

 demonstrate the causes of changes in abun- 



dance. In 1928 random samples of uncuUed 

 pound net catches in that locality revealed 

 the presence of a group with a modal value 

 at about 12.5 cm. in May (fig. 6, table 6). 

 This group increased in length and in relative 

 dominance as the season progressed. By Sepj- 

 tember this group had reached the modal 

 value of about 17 cm. and completely dominated 

 the pound net catch for that month. From 

 previous age analysis it is evident that this 

 dominant group consisted of fish spawned in 

 1927. In 1928 this brood was too small for 

 market until September, and then only the 

 larger individuals of thisclass were marketed. 

 Although observations were discontinued in 

 September, it is known from reports by pound 

 net fishermen that these small fish continued 

 to be present in considerable numbers to the 

 end of the season, about November 1. 



18 



