deeper, rocky sea bottom where the sea bass 

 were concentrated. When spots of good fishing 

 are once found, the trawler could stay on these 

 locations longer by means of her modern 

 depthfinder. 



Although the trips by the linston College 

 averaged a day longer than the rest of the 

 fleet of small boats, her catches consistently 

 were three to four times greater than the 

 average for the smaller vessels. Because of 

 the possible selection due to difference in size 

 and modification in gear, size of vessel, and 

 greater efficiency through more modern equip- 

 ment, her catches have been analyzed sep- 

 arately from the rest of the fleet and included 

 with them only in total catch statistics. Ob- 

 servation of her landed catches revealed about 

 the same size composition as those of the 

 other smaller vessels; her total catch and 

 her catch per day's fishing, however, were 

 materially higher because of her larger nets. 



Having shown that the changes in hydro- 

 graphic conditions were accompanied by erratic 

 changes In catch per day's fishing. It remains 

 to point out that the marked changes in the 

 size composition of the catch previously de- 

 scribed were regularly associated with changes 

 in water temperature, indicating that the latter 

 had caused the fish to move about. For ex- 

 ample, during the "cold" winter of 1931, when 

 the zone of water 45° F. or warmer was 

 relatively narrow, the principal catches of 

 scup were in the southern part of the ground 

 and consisted of relatively more large fish 

 than small (fig. 8). In the following two "warm" 

 winters (1932 and 1933), when the zone of water 

 45° F. or warmer extended over a com- 

 paratively large extent of sea bottom, catch 

 of scup consisted mostly of small and medium 

 sizes. The scup apparently scattered over the 

 area and were less available than in 1931, as 

 indicated by the decline in catch per day's 

 fishing In 1932 and 1933 compared to 1931 

 and by Increase In area of the plots of the 

 localities of catch (figs. 10, 11, and 12). 



With the sudden chilling of the water in 

 February 1934, the zone of warm water In 

 March was a narrow strip out over the edge 

 of the shelf, similar to the condition In 1931. 

 The size composition of the catch In this 



southern area consisted of relatively more 

 of the large scup. This was in direct contrast 

 to January before the cooling began when the 

 band of warm water presumably was present 

 well inshore, in which area the scup catches 

 were mainly small and medium fish. 



In 1935 the cooling of the water was more 

 gradual from January to March when by the 

 latter month the zone of 45° F. or warmer 

 water was over about the same narrow region 

 as In 1934. The size composition likewise 

 changed from small and medium fish in Janu- 

 ary to relatively more large fish in March, 

 especially in catches made in the southern 

 part of the ground. 



Thus it appears that because of the erratic 

 changes in size composition even within short 

 parts of a single season occurring simul- 

 taneously with marked changes In hydrographlc 

 conditions, that the fluctuations in the catch 

 per day's fishing reflect changes in availability 

 caused by movements of fish more than 

 changes in abundance. 



Summary of Winter Fishery 



1. The offshore fishery for scup, sea bass, 

 and fluke has developed rapidly since the 

 winter of 1929, both in the number of vessels 

 and in total catch. The catch of scup in- 

 creased from approximately 1.7 million pounds 

 in the winter of 1931 to 3.8 million pounds in 

 1935. 



2. The fluctuations in the catch of scup, as 

 measured by catch per day's fishing, reflect 

 changes in availability more than changes In 

 abundance. 



3. Sharp changes in size composition of 

 the scup catches from large fish in one winter 

 to smaller sizes In other winters and vice 

 versa and similar changes within short pe- 

 riods of a single season are apparently cor- 

 related with changes in hydrographlc condi- 

 tions. 



4. With considerable cooling of the water 

 in the late autumn and winter from Cape 

 Ilatteras to Cape May, scup are generally 



46 



