Tatle 8. —Average modal lengths of scup at 

 beginning and end of summer season during 

 the first U years of age. 



During the following 3 years (from 1929 to 

 1932), a series of successful broods con- 

 tributed to high yields in each year from 

 1929 to 1935, inclusive, throughout New Jersey. 

 The 1928, 1930, 1931 broods were successful, 

 and only the 1929 year class was relatively 

 poor. Although observations of size and age 

 composition of the catches of the summer 

 fishery terminated with 1932, it is believed 

 that there has been no marked diminution of 

 subsequent annual increments of broods of 

 young fish to the stock, for the yield of the 

 pound net fishery has continued at a high 

 level (fig. 3). This belief is further supported 

 by the presence in the southern winter trawl 

 fishery (fig. 8) of large numbers of fish 

 spawned in the summer of 1932. 



The New Jersey pound net fishery for scup 

 depends to a large extent upon the younger 

 and smaller sizes of fish, 2-, 3-, and 4-year 

 olds (7 to 9 inches, approximately) being 

 generally available to the inshore pound nets. 

 This means that any great diminution in the 

 number of the smaller sizes of scup through 

 unsuccessful spawning or other causes would 

 be quickly reflected in the pound net catch 

 within 1 or 2 years following the spawning 

 season of the below- aver age brood. To main- 

 tain the abundance at a high level, there must 

 be a continuous series of years or at least 

 alternate years of successful broods in suffi- 

 cient abundance to offset a decline resulting 

 from a poor spawning season. Also, a series 

 of successive poor spawning years would be 

 expected to result in extremely poor yields 

 in the pound net fishery in a relatively short 

 time. The low yields prior to 1929 (fig. 4) 



3 

 O 



a. 



\- 



X 



o 



2.0 



1.5 



1.0 



5 10 15 20 25 30 35 40 



LENGTH (CM.) 



I 1 — I 1 1 1 1 1 1 1 — I 1 1 1 1 r— 1 



I 2 3 4 5 6 7 8 9 10 II 12 13 14 15 16 

 LENGTH (INCHES) 



2 3 4 

 AGE (YEARS) 



Figure 7.— Length, weight, and age curve tor scup. 



were no doubt due to unsuccessful spawning 

 just as the high yields after that year were 

 due to successful reproduction in 1927 and 

 subsequent years. 



Transition from pound nets to off - 

 shore vessels . — The success of the 

 several year classes (1927-31) was also re- 

 flected in the catch of the offshore summer ves- 

 sel fishery (purse seiners and otter trawlers). 

 Although it has not been possible to measure 

 reliably changes in abundance by standard unit 

 of effort based on this fishery, it is known that 

 the vessel fishery has had little difficulty in 

 catching large quantities of scup during the 

 past several summers (1929-35). The pro- 

 portion of large-sized scup in the samples 

 of available vessel-fishery catches was higher 

 than it was for those from the inshore pound 

 net catches. This suggests that as scup reach 

 the age of about 4 years, they become less 

 available to pound nets in the close in^ore 



20 



