PROGRESS IN BIOLOGICAL INQUIRIES, 1931 449 



marked increase in the scrod catch, the cause of which will be dis- 

 cussed later. 



The increasin<j:ly intensive fishery for " large haddock," combined 

 with the nonappearance of any year class of juveniles comparable to 

 those of 1920-1922 to recruit the ranks, resulted in a rapid decline 

 in the stock of fish which was necessarily reflected in the catch. The 

 staggering nature of this decline is illustrated by records of one large 

 group of trawlers. The average catch per trawler per day's fishing 

 of this group on all banks decreased from about 19,000 pounds in 

 1927 to about 5.500 pounds in 1930. 



It is obvious that there is no reason to expect an increase in the 

 haddock population except through the appearance of numerous 

 young from a successful spawning season, or through the immigra- 

 tion of large numbers from some great reserve stock not now known. 

 The latter is a possibility frequently suggested by those connected 

 with the fishery, but we have as yet obtained no data which in any 

 way support it. Consequently, our hope for the immediate future 

 must lie in the small haddock now present on the banks but still too 

 small for commercial use. It is these fish which will determine the 

 trend of the fishery during the next several years. 



Work carried on during the past year, both at sea and on shore, 

 has shown that there is now present on the banks a group of small 

 haddock forming the most numerous year class which has appeared 

 during the past several years. In the latter part of 1931 the largest 

 individuals of this group were of sufficient size to be used as scrod, 

 and their presence was reflected in the commercial catch by a re- 

 markable increase in the scrod landings during the latter part of the 

 year. By the summer of 1932 the main part of this class should be 

 of scrod size and by the following summer the majority should 

 qualify as " large haddock." But this will vary considerably on dif- 

 ferent banks according to the growth rate of the fish in different 

 regions. On Browns and Western Banks this group appears to be 

 present in considerable numbers; but due to a slower growth rate, 

 the fish are of smaller size and consequently will not affect the com- 

 mercial catch until later. 



At present Ave are in no position to predict how far this influx of 

 young haddock will go in restoring the fishery to the abundance of 

 the past few years. Before such forecasts are possible it will be 

 necessary to follow several groups through their life span in the 

 commercial fishery to determine what effect a year class of a given 

 abundance will have on the commercial catch over the period of years 

 through which it is subject to the fishery. It seems safe to predict, 

 however, from our present data, that the catch of scrod per day's 

 fishing should continue at a high level during 1932, while there will 

 be no permanent improvement in the catch of " large haddock " 

 until the present scrod class reaches a sufficient size to qualify as 

 such. On Georges Bank this should take place during the fail of 

 1932 and spring and summer of 1933, though some effect may be 

 felt in the catch of " large " as early as the summer of 1932, especially 

 in the Channel region. 



It should be remembered, however, that the present fleet is larger 

 than that which was operating when the 1920-1922 group was of 

 scrod size. It is possible that the destructive effect of the larger 



