PROGRESS IN BIOLOGICAL INQUIRIES, 193 3 323 



(Browns, Sable Island, etc.). The 1931 class, which came into the 

 fishery in the late fall of 1933, to some extent will augment the catch 

 in 1934 but its etfect cannot be determined at present owing to our 

 inability to collect suflicient data at sea during the past year. How- 

 ever, a very rough approximation of the relative abundance of this 

 year class, obtained from the limited data collected on trawler trips 

 in 1932 and from commercial catch data for November and December 

 1933 is that the 1931 class is somewhat less than half as abundant as 

 was the 1929 class at the same age. If this be the case, this group 

 may be sufficiently large to maintain the commercial haddock pop- 

 ulation on Georges Bank at about the same level as in 1933, pro- 

 viding that the majority of the large otter trawlers continue to do 

 most of their fishing on the eastern banks rather than on Georges. 

 It appears more probable, however, that the catch per trawler day 

 in 1934 will be less than in 1933. 



The catch in 1935 depends on the degree of success of the 1932 

 spawning season. Fish of this year class would have averaged 

 somewhat less than 35 centimeters in length during 1933 and if abun- 

 dant would have been taken in large numbers by the commercial 

 trawlers. No reports of such catches have been received during the 

 past year; consequently, it appears that the 1932 class was a rela- 

 tive failure. Haddock of this year group can provide the only addi- 

 tions to the fishery in 1935 ; if it was a failure as the above evidence 

 indicates, the level of abundance in 1935 must again show a marked 

 decline. 



Eastern hanks fsherij. — Under eastern banks we have grouped all 

 the haddock grounds east of the Fundian Channel (the deep gully 

 separating Georges from Browns Bank). From present data this 

 gidly appears to form a complete barrier to the movements of the 

 young haddock during the entire year and to the older fish during 

 most of the year. For example, the 1929 year class showed no move- 

 ments across the channel until their fourth winter (that of 1932-33) 

 and the older fish have shown mass movements across this channel 

 only around the spawning season. The details of these move- 

 ments have not yet been worked out. 



The chief distinguishing characteristic of the haddock poi)ula- 

 tions of the regions east and west of the Fundian Channel is the 

 difference in the rate of growth of the younger fish. For example, 

 on Georges Bank the 1929 class reached commercial size during the 

 winter of 1931-32 and spring of 1932, while on the eastern banks 

 the same year class did not reach commercial size until the spring 

 and summer of 1933, a difference of about a year and a half. The 

 same difference is being indicated by the 1931 year class. A dif- 

 ference in growth rate probably continues in the older fish but is less 

 evident because of increasing intermixture of the stocks. 



As a result of growth differences the 1929 class did not have its 

 full effect on the eastern banks fishery until the summer of 1933. 

 Only a few boats were fishing the area at that time but shortly after- 

 ward most of the large otter trawlers shifted their activities from 

 Georges to the eastern banks in the vicinity of Sable Island, where 

 extremely good catches of scrod haddock were being taken. These 

 large scrod catches brought the average catch per trawler day for 

 1933 up to a level approximately 40 percent higher than for 1932. 



