FISHES OF THE GULF OF MAINE 



245 



one from the western basin in 160 fathoms, the 

 other from off Gloucester, both of them taken 

 many years ago. But they must be rather com- 

 mon on the muddy bottoms of the deeper parts of 

 the Gulf in 85 to 125 fathoms, for we have caught 

 more than 100 of them at various localities on 

 recent trawling trips. No doubt it is because few 

 vessels ever fish on these grounds, which are not 

 productive either of cod or of haddock, that the 

 presence of grenadiers there has been overlooked. 

 A grenadier, too, was reported from the slope of 

 Jeffreys Ledge, in about 50 fathoms, during March 

 1934. 



Grenadiers, together with the long-finned hake 

 (p. 232), are the most abundant fish on the con- 

 tinental slope abreast of the Gulf below 100 

 fathoms. 6 



Rough headed grenadier Macrourus berglax 

 Lacepede 1802 8 



Rat-tail; Onion-eye 



Jordan and Evermann, 1896-1900, p. 2583. 



Description. — This species resembles the com- 

 mon grenadier (p. 243) so closely in general appear- 

 ance that we need only indicate the points of 

 difference. Most obvious of these are that its 

 snout is shorter and blunter, with more highly 

 arched dorsal profile; that it has 4, 5, or 6 distinct 

 ridges on the top of its head; that its head is 



1 For a list of captures on the continental slope during the early cruises of 

 the U. S. Fish Commission vessels, see Goode and Bean (Smithsonian Con- 

 tiib. Knowl., vol. 30, 1895, p. 394). 



• Authorities disagree as to the correct scientific name of this grenadier, for 

 while it has usually been referred to as berglai Lacepede, 1802, Jensen (Spolia 

 Zool., Mus. Hauniensis, Copenhagen, vol. 9, 1948, p. 178) prefers the species- 

 name fabricii that was applied to it more recently by Sundevall, 1840, on the 

 ground that the grenadier to which Lacepede gave the name berglax was 

 another fish, Coryphaenoides Tu-ptstris Gunnerus, 1765, which is commonly 

 termed "berglax" on the west coast of Norway. 



relatively larger (about one-fourth to one-fifth 

 the length of the fish, only one-sixth to one-seventh 

 in the common grenadier) ; that its trunk is rela- 

 tively stouter (about six times as long as it is deep) ; 

 that its vent is close to the point of origin of the 

 anal fin with the skin scaly around it, and no 

 darker colored than on the back; and that the 

 serrations on the large spine in the first dorsal 

 fin are so fine that they are hardly visible. 



Furthermore, there are fewer (about 124) rays 

 in the second dorsal fin, but more rays (about 148) 

 in the anal than in the common grenadier, and 

 its first dorsal fin is of rather different outline. 

 The second dorsal fin, too, is relatively higher than 

 in the common grenadier and with its membrane 

 more developed (compare fig. 120 with fig. 119), 

 while the filamentous prolongation of the outer 

 ray of the ventral fins is not so long in berglax as 

 it is in bairdii. The structure of the scales, too 

 (visible to the naked eye), is diagnostic, for those 

 on the head and shoulders of berglax are armed 

 with either one longitudinal row of spines (10-12 

 rows of spines on each scale) , or with up to 3 or 4 

 radiating ridges of spines while those farther back 

 each have a single row of spines, which together 

 form conspicuous longitudinal ridges along each 

 side of the rear part of the body. 



Color. — The only newly caught specimens we 

 have seen were ash gray below as well as above; 

 with the chest a little darker; with the rear edges 

 of the scales on the rear part of the body still 

 darker; with the anal fin narrowly dark edged; 

 with the first dorsal fin and the pectoral fins sooty; 

 and with the ventral fins sooty, except that the 

 outermost rays are white after preservation in 

 alcohol. 



Size. — This fish is larger than the other grena- 

 diers (p. 243). It is credited with a maximum 



Figure 120. — Rough-headed grenadier (Macrourus berglax), Banquereau Bank. 



H. L. Todd. 



From Goode and Bean. Drawing by 



