of the general offshore region, during which 

 temperatures were taken at several stations 

 on a profile extending from about the 10- 

 fathom line out to the 100-fathom con- 

 tour. These data were supplemented by 

 temperatures taken by certain fishing captains 

 at various fishing spots in the general area 

 from about lat. 36° N. to about lat. 38^ N. in 

 depths 40 to 60 fathoms. The sharp drop in 

 temperature did not occur in February as 

 was the case in 1934; instead, there were 

 indications of a gradual cooling from January 

 through to March, so that by the latter month 

 the zone of water 45° F. or warmer covered 

 about the same extent of sea bottom, at least 

 off Chesapeake Bay, as in 1934. There was, 

 however, in 1935 a shift in best fishing loca- 

 tion from a somewhat central inshore area, 

 depths 20 to 50 fathoms, in January to a more 

 offshore area extending more to the north and 

 south in depths of 50 fathoms or more in 

 February. In March, fishing continued to be 

 offshore, but with some shift to a more 

 southerly inshore area, with 20- to 50-fathom 

 depths (fig. 11). Thus, there was general 

 correspondence to the changes in fishing 

 locations in 1934. Likewise in 1935, as in 1934, 

 fishing in the northern area yielded smaller 

 catches per unit of effort in March than in 

 January or February; and in the southern 

 area, on the other hand, catches were better 

 in March than in the preceding months. 



Not only have the marked changes in water 

 temperature affected the location of best 

 fishing, but it also affected the proportions 

 in the catch of scup, sea bass, and fluke 

 and, in some years, croakers. Obviously, 

 the fleet is not particularly interested in 

 any one species, but rather in the amount 

 of money that can be made. Sea bass and 

 fluke usually bring a higher price than scup 

 or croakers, and special effort is often di- 

 rected toward the former two species. If sea 

 bass and fluke are not easy to catch, fisher- 

 men do not hesitate to seek scup or croakers 

 (the latter especially in March) when they 

 are readily available and numerous. 



We have already seen that the best catches 

 have been made in bottom water warmer than 

 45° F. (figs. 10 and 11). This was especially 

 true of the scup catches. For example, in 



1931 when the zone of warm water was con- 

 fined to a rather narrow band far out near 

 the edge of the Continental Shelf, good catches 

 were made in the southern offshore part of 

 the ground. In that winter, more scup than 

 sea bass or fluke were caught. Of a total catch 

 of approximately 3,415,000 pounds landed at 

 Virginia ports, about 50 percent was scup, 

 23 percent sea bass, and 27 percent fluke. On 

 the basis of catch per day's fishing for the 

 season, scup also exceeded either of the other 

 two species (fig. 12, table 16). 



The dominance of scup in 1931 might have 

 been the result of (1) hydrographic conditions 

 which concentrated scup in the southern in- 

 shore shoal portion of the zone of water 45° F. 

 or warmer, where they were readily available 

 to the gear, and (2) the lesser availability of 

 sea bass and fluke, which favor somewhat 

 different areas than scup, probably because 

 of preference for slightly different tempera- 

 ture and bottom type. Observations from 1931 

 to 1935 have revealed that the best catches of 

 sea bass are usually taken in deeper and 

 slightly warmer water than are scup and on 

 rocky bottom in contrast to smooth, hard, 

 sandy bottom frequented by scup. The best 

 catches of fluke are usually from deeper 

 water than are scup, but unlike either sea 

 bass or scup, fluke are caught in more 

 northerly part of the ground on soft, smooth, 

 mud bottom (about lat. 37° n. to about lat. 

 38° 30' N., 40 to 80 fathoms). It is probable 

 that the preference of each species for a 

 special kind of bottom modifies the move- 

 ments of the fish affected by changes in tem- 

 perature, for although the water over a region 

 may have a temperature tolerated by the 

 species, the latter may not remain there for 

 any length of time if the bottom is not suit- 

 able. 



The best catches of croakers in some years 

 are made in December in the region of rela- 

 tively warm and shoal water south of Cape 

 Hatteras, but in other winters (as in 1934 and 

 1935) best catches were made in March from 

 near the beach, out to about the 50-fathom 

 line. It is believed that this is part of the 

 spring migration to the summer fishing 

 grounds, for by the end of March large 

 catches are often taken by traps in the inshore 



42 



