STUDIES ON THE STRIPED BASS OF THE ATLANTIC COAST 



13 



in the same manner. This is so because although this particular seine fishery at 

 Point Judith was a new one, it was not operating on a virgin stock, for the striped 

 bass is a highly migratory species and is the object of intensive fisheries of different 

 types along the entire Atlantic coast. A more logical explanation is that this down- 

 ward trend in annual average weight over this period was brought about by the de- 

 creasing numbers of large fish that formed the remnant of a dominant year-class 

 produced some years before. That there was a definite decrease in the proportion 

 of large fish making up the catch from 1930 to 1936 is evident from figure 31, in 

 which the percentages of small, medium, and large fish taken in each year are shown. 

 The peak in the annual average weights at 1930 (fig. 7) was caused by the compara- 

 tively great numbers of large fish that made up the catch. Thereafter the composition 

 of the yearly catch showed a decreasing percentage of fish from the larger size-cate- 

 gories (except in 1935). It seems logical, therefore, that a fairly good remnant of 

 a dominant year-class, whose members had attained a large size, existed in 1930, 

 and that in each successive year this remnant became increasingly smaller, thus 

 producing the downward trend in the annual average weight of bass making up 

 the catch in these years. The sharp drop in average weight in 1936 was primarily 

 due to the appearance of the 1934 dominant year-class in the commercial catch. 



NUMBERS AND SIZES OF STRIPED BASS 

 MAKING UP THE ANNUAL CATCHES BT SEINE 

 AT POINT JUDITH. R I . 1928 - 1937 



INI IH« 



Figure 8.— Numbers and sizes of striped bass making up the annual eatciics by seine at Point Judith, R. I., 1928-37. The left 

 column in each year is for April and May, and the right column for June to November. The fishing intensity has been equalized 

 throughout. 



The tremendous numbers of 2-year-olds in this year is well shown in fig. 8. It will 

 also be noticed that there was an exceedingly small percentage of large fish in this 

 year. The increase in annual average weight in 1937 was due to the increase in 

 size of the members of the 1934 dominant year-class— at this time 3-year-olds. If 

 no other dominant year-class comes along for a considerable period of years, it is to 

 be expected that the annual average weight of the striped bass making up the yearly 

 catch will climb steadily to a certain limit, i. e., until the numbers and larger size of 

 the striped bass born in 1934 become insufficient to increase the average weight of 

 the individuals making up the entire catch. If the production of young then con- 

 tinues at a low level, the annual average weight should show a steady decline until 

 the members of another dominant year-class attain sufficient size to start it on an 

 upward trend again. It seems likely that it is the latter part of this cycle that is 

 shown in figures 6 and 7. 



The question of precisely what caused the appearance of the dominant year-class 

 of 1934 is of especial interest. Judging from the catch records shown in figures 4, 6, 

 7 and 8, there can be little doubt that this year-class represents the largest production of 

 striped bass on the Atlantic coast in the past half century or more. Yet it is apparent, 

 as has been pointed out, that the parental stock in 1934 was probably as small as it 

 ever as been (see figs. 4, 6, and 8) (the catch in northern waters can be used as an 

 indication of the size of the stock from Massachusetts to Virginia since this species is 

 highly migratorv within these limits). It would seem, therefore, that the production 



