270 Memoir Sears Foundation for Marine Research 



Bank during March when the water is coldest, and likewise in the inner parts of the 

 Gulf of Maine, if any R. senta remain there in shallow water of 30—40 fathoms through 

 the late winter and spring. 



The fact that R. senta has never been reported from water colder than about 2° C 

 (36° F) suggests that low temperature is the barrier that bars it from regularly populating 

 the more easterly sections of the Nova Scotian (Banquereau) or the Newfoundland banks, 

 for these bottoms are flooded yearly with water as cold as 0° C (or even a little colder) 

 at seasons when the icy outflow from the Gulf of St. Lawrence (in the first case) or the 

 southerly expansion of the Labrador Current (in the second) is at its maximum. At the 

 other extreme, some of the specimens that have been taken along the continental edge 

 off New England and farther south may have been from water about as warm as 1 1° C 

 (52° F); however, most of them have been taken from water with temperatures between 

 about 6° C (42 or 43° F) and about 9-10° C (49 or 50° F).i" 



Generally R. senta has been taken from water at least as saline as 32.6 "/oo, most 

 of them from water with salinities higher than 32.8 "/oo; undoubtedly specimens along 

 the continental edge live in salinities as high as 34.7 "/oo and probably as high as 35.0- 

 35.4 "/oo- There is nothing in the available records to suggest that R. senta carries out 

 any regular seasonal migrations. 



Numerical Abundance. Most of the records for this particular Skate report the cap- 

 ture of odd individuals only. However, 57 specimens of i?. senta^ out of a total catch of 

 495 Skates, were taken in 37 trawl hauls on Georges Bank in September 1929, thus 

 giving an average of one to two per haul and indicating a population density similar to 

 that of R. ocellata (about two per haul) or R. laevis although much smaller than that of 

 R. radiata (about eight to nine per haul). Off^ southern New England and New Jersey, 

 13 R. senta out of a total catch of 77 Skates were taken in eight trawl hauls deeper than 

 100 fathoms (about one to two per haul).^** 



Range. Atlantic shelf of North America from the latitude of Charleston, South 

 Carolina to the Nova Scotian Banks and Gulf of St. Lawrence; as a stray to the southern 

 part of the Newfoundland Bank. 



Occurrence in the Western North Atlantic. Raja senta, once considered a rare species, 

 is now known to occur generally in water of sufficient depth throughout the western 

 side of the Gulf of Maine 1*^ and along the Nova Scotian side of the Bay of Fundy; this 

 distribution suggests that it will prove as widespread at appropriate depths in the eastern 

 side of the Gulf as it is on Georges Bank. It is known also from the southeast slope of 

 Browns Bank,"* from LaHave Bank off southeastern Nova Scotia, and from Emerald 

 Bank off Halifax, as well as from the estuary of the St. Lawrence River. It has been 



143. To judge from the depths and localities of capture; one specimen from the offing of South Carolina was taken 

 in water of 4° C (39.3° F). 



144. By Albatross III between Long. 6 7° 10' and 72°2o' W, May ii-iS, 1950. 



145. We have taken it on several occasions in the trough west of Jeffreys Ledge, in the west central part of the Gulf 

 near Cashes Ledge, and at three stations east and southeast from Cape Cod; it has been reported from the Bay 

 of Fundy and off Provincetown at the tip of the Cape. 



146. Trawled by Caryn of the Woods Hole Oceanographic Institution, June 18, 1949, at Lat. 42°! 8' N, Long. 65°oi' W, 

 in 380-420 fathoms. 



