462 BULLETIN OF THE BUREAU OF FISHEEIES 



have short ventral fins." After the rockling is 17 to 20 mm. long the structure of 

 its first dorsal fin serves to identify it. These larger fry are silvery, probably awaiting 

 their descent to bottom before assuming the dull colors of the adult. 



161. Cusk {Brosmius Irosme MiiWer) 

 Jordan and Evermann, 1896-1900, p. 2561. 



Description. — The cusk is separable from all its Gulf of Maine relatives at a 

 glance by the fact that it has but one dorsal fin. The relationship of the anal and 

 dorsal fins to the caudal and the outline of the latter are also characteristic, all 

 three being continuous at the base but separated by notches so deep that they are 

 obviously distinct, and with the caudal evenly rounded. The cusk is more slender 

 than a hake, being only about one-fifth to one-sixth as deep as long, round-bodied 

 in front, compressed behind the vent, and tapering evenly backward to the base of 

 the caudal fin. Themouth is large, gaping past the eye and set slightly oblique, with 

 small, sharp, curvedteeth. The snout is blunt at the tip. Theupper jaw incloses the 

 lower when the mouth is closed, the eye is of moderate size, the chin bears a barbel, 

 and the entire head and trunk are clad with small scales. The dorsal fin (85 to 105 

 rays) runs the whole length of the back from the nape and is of uniform and moderate 

 height from end to end with rounded corners. The anal is similar to it in outline 

 but only slightly more than half as long (71 to 76 rays). The pectorals are rounded 

 and about half as long as the head. The ventrals are about as long as the pectorals, 

 with their 5 rays free at the tips, and are situated slightly but obviously in front 

 of the pectorals. All the fins are so tliick and fleshy at their bases that it is only 

 near the margins that the raj's are apparent. 



Color. — The cusk varies in color, no doubt conforming to the bottoms on 

 which it lives. The upper parts range from dark slaty to dull reddish brown 

 or pale yellowish, paling to grayish on the lower sides and to dirty white on the 

 belly. Old fish are plain colored; in small ones, however, the sides are often barred 

 transversely with about half a dozen yellowish bands. The pectorals and ventrals 

 are of the same color as the sides and the ventrals are sooty at their tips. The most 

 characteristic color mark is that all three vertical fins — dorsal, caudal, and ventral — 

 which are of the general body tint at their bases, are black at the margin and nar- 

 rowly edged with white. 



Size. — Cusk grow to a maximum length of 3 feet and to a weight, it is said, of 

 30 pounds, but those caught in the Gulf of Maine average only 1)4 to 2}4 f^et long 

 and from 5 to 10 pounds in weight. 



General range. — Both sides of the North Atlantic, chiefly in moderately deep 

 water, north to the Newfoundland Banks, Gulf of St. Lawrence, Labrador, and 

 Greenland; south regularly to Cape Cod and the South Channel, rarely to southern 

 New England, and occasionalh' to New Jersey on the American coast. 



^^ The Arctic three-bearded rockling (Gaidropsarus argeutatu^ Rheinhardt) was reported from Massachusetts Bay by Gill 

 (1864a, p. 241), who speaks of a specimen from Nahant; also by Storer (18G7) ,who writes that many were picked up on Nahant 

 Beach during one tide in the summer of 1860. Three more were found in the surf at West Beach, Beverly. All these specimens, 

 however, were the young silvery fry. As it was not known at the time that the common rockling passed through such a stage, 

 ami since neither Gill nor Storer noted the number of barbels, it is more likely that they belonged to the four-bearded species than 

 to the Arctic species. Should the latter prove to be a denizen of the Gulf the number of its snout barbels (p. 3S5) would serve for 

 its identification. 



