72 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



Bank also, but is far less plentiful there than other 

 skates, to judge from the fact that trawl hauls in 

 September 1929 brought in only 37 of them, and 

 that we counted only 8, from 42 hauls on the 

 Eugene H; in June 1951, fishing from Nantucket 

 Lightship to the south central part of Georges. 

 We have trawled it at 50 to 250 fathoms off 

 southern New England. To the eastward and 

 northward, it is recorded on La Have and Emerald 

 Banks at 50 to 100 fathoms, and in the Gulf of St. 

 Lawrence at 82 to 178 fathoms. 



Thorny skate Raja radiata Donovan 1807 



Starry skate 75 



Bigelow and Schroeder, 1953, p. 255." 

 Garman, 1913, pi. 21, fig. 2." 



Description. — The thorny skate can be identified 

 at a glance among skates of the Gulf of Maine by 

 the fact that the row of thorns with which the 

 midline of back and tail is armed are not only 

 large and conspicuous, but do not number more 

 than 19 at most from the nape back along the tail. 

 There are also 2 or 3 large thorns on each shoulder; 

 and one in front of each eye and one behind it ; one 

 close to the inner end of each spiracle; and other 

 smaller thorns scattered on snout, pectoral fins, 

 and tail. The bases of the thorns on the pectorals 

 are star-shaped, a very distinctive character; 

 those of the still larger thorns along the midline of 

 the back are oval. Adult males have 2 rows of 

 hooked, erectile thorns near the outer corners of 

 the pectorals. 



The anterior angle of the disc is considerably 

 more obtuse than a right angle (1 10-140°), and the 

 tip of the snout is blunt with the margins bulging 

 somewhat a little in front of the level of the eyes; 

 the outer corners of the pectorals are less broadly 

 rounded than in either the little skate or the big 

 skate; and the two dorsal fins may either be 

 joined at the base or be separated by a short 

 space. There are 36 to 46 series of teeth in each 

 jaw, those of females and of young males with low 

 cusps that are worn nearly smooth along the 



78 When the tirst edition of this book appeared, it was an open question 

 whether the thorny skate of American waters (named /'. scabrata by Garman 

 1913) was identical with the thorny skate of northern Europe (R. radiata 

 Donovan, 1807). Our subsequent comparison of American specimens with 

 others from Greenland and Norway has convinced us that they all belong to 

 the one species, which must be called by the older of the two scientific names. 



'• FiKiire lot Gam 's plate 2! is nol ofs thorny skate, as it is named in the 



accompanying caption, bul isol l small pecimen of the big katethat we lia\ e 

 examined. 



older rows; those of mature males a little sharper 

 and spaced a little more widely. 



Color. — Brown above, either uniform or slightly 

 clouded, or spotted with darker, small specimens 

 more conspicuously so than larger. Sometimes 

 there is a white spot beside each eye, one on either 

 side abreast of the nape, and another on each side 

 on the rear part of the disc. The lower side is 

 white, sometimes with irregular sooty or brownish 

 blotches. Garman mentions a partial albino, 

 white above with a few reddish brown and brown 

 spots. 



Size. — The thorny skate is about 4 inches (100 

 mm.) long from snout to first dorsal fin at hatch- 

 ing. The largest specimens so far recorded from 

 American waters have been about 40 inches for 

 the Nova Scotia Banks, 35% inches for Georges 

 Bank, and about 31 inches for Massachusetts 

 Bay. But some males may mature when only 21 

 to 22 inches long. One 32 inches long is about 23 

 inches wide. 



Habits. — The thorny skate is a cool water fish, 

 at home in temperatures from about 50° or so down 

 nearly to the freezing point of salt water. It is 

 also restricted in general to depths greater than 

 about 10 fathoms, even in the northernmost part 

 of its range. In the Gulf of St. Lawrence it lives 

 indifferently on the ice cold banks and in the 

 warmer water on the bottom of the deep Lauren- 

 tian Channel. Average catches of 1 per haul at 

 26 to 35 fathoms, 22 per haul at 36 to 49 fathoms, 

 and 5 per haul at 50 to 75 fathoms, in 42 trawl 

 hauls, by the Eugene H fishing from Nantucket 

 Lightship, the central part of Georges Bank, 

 June 1951, suggest a rather definite preference for 

 the intermediate depth zone, perhaps because of 

 the food supply. But thorny skates have been 

 taken at many stations, also, down to 336 fathoms 

 off the American coast, and as deep as 459 fathoms 

 near Spitzbergen. 



The stomachs of thorny skates caught on 

 Georges Bank contained shrimps, spider crabs, 

 anemones, hydroids, and fish digested past 

 identification. 



The egg cases vary considerably in size, prob- 

 ably depending on the size of the parent fish. 

 One from a fish 32 inches long, taken on Georges 

 Bank, measured 3 by 2% inches exclusive of the 

 horns. Others that have been measured from the 

 Nova Scotia Banks ranged from 3 to 3% inches in 

 length. They are flat on one side, strongly convex 



