FISHERY BULLETIN: VOL. 70, NO. 3 



soft mud and are chiefly caught over broken 

 ground, gravel, pebbles, clay, and smooth hard 

 sand. However, there are no conspicuous dif- 

 ferences in the sediments of the Continental 

 shelf east and west of Nantucket Shoals (Uchupi, 

 1963). Sediments on Georges Bank consist of 

 coarse sand and scattered patches of gravel. In 

 the area between Nantucket Shoals and Hudson 

 Canyon, there is a nearshore zone of silty sand 

 and sandy silt and scattered patches of gravel. 

 Between the 30- and 60-m isobaths is a zone of 

 coarse sand and scattered patches of gravel. 

 From the 60-m isobath to the edge of the shelf, 

 the sediments are similar to those in the basins 

 of the Gulf of Maine and consist of silty sand, 

 sandy silt, and silt. 



On a basis of a stomach content analysis of 

 haddock collected on Georges Bank during 1953- 

 54, Wigley (1956) concluded that haddock are 

 exceedingly omnivorous. Their diet consisted 

 principally of sedentary or slow-moving inverte- 

 brate animals. The primary food organisms in 

 decreasing order of abundance were crustaceans, 

 mollusks, echinoderms, annelids, and fish. There 

 was considerable variation in dietary compo- 

 nents from one location to another. Having no 

 supplementary data on the distribution of ben- 

 thic fauna, it could not be determined if this 

 variation in diet was related to faunal compo- 

 sition. More recent studies of the distribution 

 of benthic fauna on the continental shelf between 

 Nova Scotia and Long Island (Wigley, 1961; 

 Wigley and Mclntyre, 1964; R. L. Wigley — per- 

 sonal communication) show that haddock prefer 

 crustaceans to other food organisms and that 

 the quality and quantity of the benthic fauna to 

 the west of Nantucket Shoals are more than 

 adequate to support a large population of had- 

 dock. It is possible that competition for food 

 by the very rich summer and fall populations 

 of such species as the spiny dogfish, silver hake 

 {Merluccius bilinearis) , and red hake {Urophijc- 

 is chuss) is a factor in restricting the haddock 

 from the Middle Atlantic Bight. 



As mentioned previously, the yellowtail 

 flounder is common both to the east and west of 

 Cape Cod at all seasons of the year. Bigelow 

 and Schroeder (1953) observed that the re- 

 stricted depth range and the nonmigratory habit 



of this species indicate that yellowtail can toler- 

 ate a wide range of temperature. This eury- 

 thermic tolerance is further evidenced by the 

 long spawning season and extensive spawning 

 area of this species. The yellowtail breeds over 

 its entire range and from March through Au- 

 gust. The spawning period appears to be no 

 later east of Cape Cod than to the west. In 

 addition, Bigelow and Schroeder (1953) noted 

 that individual females evidently spawn over a 

 considerable period of time for only a small part 

 of the eggs ripen simultaneously. The above 

 authors estimated that the yellowtail was subject 

 to a range of temperature from season to season 

 in one part of its area of occurrence or another 

 from about 1° to 12°C. However, the distribu- 

 tion of yellowtail off southern New England and 

 Long Island during the warmest part of the 

 year indicates that they can tolerate tempera- 

 tures at least as high as 16°C for limited periods. 



Yellowtail flounder are only found over sand 

 and sand-mud bottoms and never over rocks, 

 stony ground, and very soft bottom (Bigelow 

 and Schroeder, 1953) . This preference for sand 

 sediments is especially evident if one compares 

 the distribution of yellowtail shown in Figures 7 

 and 10 with the distribution of sediment type 

 shown by Uchupi (1963, Figure 94.1). This 

 predilection for sand sediments is also shown 

 in the data of Fritz (1965, Plates B and 14). 

 It would appear then that except at the extreme 

 northerly and southerly limits of its range, the 

 geographic distribution of yellowtail is more 

 strongly inff'uenced by bottom type than by tem- 

 perature. 



It is possible that changes in distribution oc- 

 curred which were not evident from the survey 

 data due to limitations of sampling and analysis. 

 For example, a number of groundfish species 

 inhabit areas shoaler than that covered by the 

 surveys (<30 m). Among such species is the 

 summer flounder (Paralichthys dentatiis) , 

 which is representative of species restricted for 

 the most part to the area southwest of Cape Cod 

 at all seasons of the year. Pelagic species such 

 as menhaden (Brevoortia tyrannus), a warm 

 season migrant having wide fluctuations of oc- 

 currence in the Gulf of Maine, and herring 

 {Clupea harengns harengus) , a boreal species 



654 



