322 U.S. BUEEAU OF FISHERIES 



decreases in the average abundance arise from causes which now 

 appear quite clear cut and comprehensible. An increase follows 

 one or a series of good spawning seasons while a series of poor 

 spawning years results in a rapid drop in the catch. Changes in 

 abundance from bank to bank and within the year principally are the 

 results of mass movements of the fish and appear to follow a fairly 

 regular seasonal cycle. There also is a regular decrease in the catch 

 from summer to winter and an increase from winter to summer which 

 may be the result of seasonal changes in the schooling habits of 

 the fish. 



Georges Bank -fishery {including South Channel and Nantucket 

 Shoals). — Our data show that the rapid increase in haddock land- 

 ings, from about 85,000,000 pounds in 1923 to more than 250,000,000 

 pounds in 1929, was due in part to an increase in the otter trawl 

 fleet and in part to a great increase in abundance of fish on Georges 

 Bank which during these years accounted for about 80 percent of 

 the haddock landed in the United States. This high level of abund- 

 ance was the result of a series of exceptionally successful spawning 

 seasons during the years 1920-24. 



The increase in abundance came to an abrupt halt in 1928 as 

 the result of a series of very poor spawning years, 1925-28, which 

 added relatively few young fish to the population. The commer- 

 cial stock on Georges Bank, lacking appreciable additions of up- 

 growing young fish from these poor years, in 1928 began to decrease 

 rapidly under the heav}^ inroads of fishery. However, the total 

 haddock landings continued to rise until 1929 owing to the addition 

 of new boats to the fleet and to the increased proportion of time spent 

 at sea by all trawlers. The rapid decline begun in 1928 continued 

 until 1930 and 1931 when the level of abundance was the lowest 

 in the history of the fishery. In spite of a gradual shift to the 

 use of the new V-D gear the large otter trawlers were averaging 

 but 5,000 to 6,000 pounds of haddock a day compared to the 18,000 

 to 20,000 pounds averaged in 1926 and 1927 with the less effective 

 type of trawls then in use. 



This rapid downward trend in abundance on Georges Bank was 

 finally halted by the 3'oung haddock from the successful spawning 

 year of 1929 which reached commercial size in the winter and 

 spring of 1932. As a result of this influx of young haddock the 

 scrod catch in 1932 averaged nearly three times as great as in the pre- 

 vious J^ear while the average catch per trawler day of all hadclock 

 was approximately 40 percent more than in 1931. 



By the time the 1933 season was well under way the trend in 

 the catch once more turned downward. The 1929 class had attained 

 its maximum effect in 1932 and had begun to decline in the face 

 of a still intensive fishery, and as the 1930 spawning had been a 

 relative failure there were few additions of upgrowing young fish 

 to replace those caught off by the hundreds of line trawlers and 

 otter trawlers h,ardi at work oh the banks. , Consequently, the 

 average catch per trawler day for 1933 was nearly 20 percent lower 

 than in 1932. 



The fishery on Georges Bank appears to be due for a continued 

 decline for the next 2 years unless, as is remotely possible, there de- 

 velops a considerable immigration of haddock from the eastern banks 



