448 U. S. BUREAU OF FISHERIES 



in putting business records at the disposal of our staff and providing 

 facilities for them on board their vessels and in their shore establish- 

 ments, which have made possible the progress reported in the follow- 

 ing sections, is gratefully acknowledged. 



HADDOCK 



The investigation of the haddock fishery has been carried on dur- 

 ing 1931 by several investigators under the immediate direction of 

 W. C. Herrington. 



Statistical and biological studies of the haddock poftdation. — Dur- 

 ing the past tw^o years the haddock fishery of New England has ex- 

 perienced a sharp decline, following a period of exceptional pro- 

 ductiveness. On the fishing grounds, principally Georges Bank and 

 South Channel, where the bulk of the United States landings have 

 originated during the past few years, the abundance of haddock, as 

 measured by the average catch per trawler per day's fishing, in- 

 creased markedly from 1924 to a maximum in 1927. Since then it 

 has fallen off sharply to a level in 1930 far below that in 1924. This 

 drop continued during the first half of 1931. 



The decline beginning in 1928 did not at first seriously affect the 

 fishery. By means of longer trips and fewer days spent in port, 

 the fishing time was increased until it more than compensated for 

 the decreasing abundance, so that the catch per trawler continued 

 to rise. In addition, the total catch was considerably augmented by 

 the increase in the size of the fleet through the construction of new 

 craft. As a result, the total landings continued to increase until 

 1929, although the catch per day's fishing began to drop during 

 the last part of 1927. By 1930 the level of abundance had fallen to a 

 point where the total catch could no longer be maintained, in spite 

 of increased fishing effort, and there was consequently a decided de- 

 crease in total landings in 1930 which continued in 1931. 



By combining with the statistical analysis a study of the biology 

 of the haddock stock, primarily size and age composition, growth 

 rate and distribution, the causes of this change in abundance as re- 

 flected in the catch per unit of fishing effort are gradually becoming 

 clear. It now appears that between 1920 and 1922 one or more 

 extraordinarily successful haddock year classes were produced. In 

 1924 the largest of these fish had grown large enough to increase the 

 catch of scrod haddock. In 1925 the full effect of this group was re- 

 flected in scrod landings, which were the greatest of any year since 

 1924, when our detailed records began. In addition, the larger 

 members of this class were then of a sufficient size to be included in 

 the category of "large haddock." In 1926 and 1927 as the full 

 numbers of this enormous group came within the category of " large 

 haddock " and as their total weight increased through growth, the 

 abundance of haddock on the banks, as measured by the number of 

 pounds caught per day's fishing, increased rapidly until a peak 

 was reached in 1927. Since 1927 the catch statistics do not indicate 

 the production of any year class at all comparable in numbers to 

 those of the earlier period. In fact, since 1925 the catch of scrod 

 has become successively less, in 1930 reaching the lowest point on 

 record. Following this, in the latter part of 1931 there was a 



