FISHES OF THE GULF OF MAINE 



505 



however, mollusks even as large as these are 

 swallowed whole, and we have seen many caught 

 on hooks baited with clams. In north European 

 waters wolffish are said to subsist largely on 

 mussels, and one examined by Vinal Edwards at 

 Woods Hole was full of these; none, however, were 

 found in stomachs of the fish caught on Georges 

 Bank, although mussels are plentiful there, which 

 points to a definite preference for the other shellfish 

 just mentioned. The wolffish is also known to feed 

 on large hermit crabs, on ordinary crabs, and other 

 crustaceans, on starfish, and on sea urchins, a 

 quart of the latter having been taken from one 

 caught at Eastport. 1 And Mr. Clapp's observa- 

 tions that every one he has opened contained food 

 of some sort is good evidence of its constant search 

 for anything edible. With such a diet it is not 

 surprising that wolffish are more often caught on 

 hand lines baited with cockles or clams than on 

 long lines, which are usually baited with herring. 



Breeding habits.- — The breeding habits of the 

 wolffish have not been followed on this side of the 

 Atlantic. In north European waters it spawns 

 chiefly from November until January, 2 and ap- 

 parently the breeding season is about the same 

 for it in Nova Scotian waters, and in the Gulf of 

 Maine, for McKenzie and Homans 3 report a mass 

 of eggs dragged up on February 19, in 1937, 

 some of them just hatching, while we have taken 

 larvae of 20 to 22 mm. (fig. 267), that is, 2 to 3 

 months old from the time the eggs were deposited, 

 as early as January 30 in 1913, and as late as 

 March 4 in 1920. 



The eggs, 5.5 to 6 mm. in diameter (among the 

 largest fish eggs known), yellowish, opaque, and 

 with an oil globule of 1.75 mm., are laid on the 

 bottom in shoal water where they stick together 

 in large loose clumps among weeds and stones. 

 The fish have been described as making an annual 

 shoreward journey for spawning purposes, but 

 there is little evidence of this. The precise dura- 

 tion of incubation is yet to be learned; probably it 

 is long, as it is for most of the fishes that lay their 

 eggs on the bottom. 



• Verrlll, Amer. Naturalist, vol. 6, 1871, p. 400. 



» It was formerly thought to spawn in spring, but Mcintosh and Prince 

 (Trans. Roy. Soc. Edinburgh, vol. 35, Pt. 3, No. 19, 1890), to whom we owe 

 all that Is known of its early larval development, proved it an autumn and 

 winter spawner both by examination of Its ovaries and by the discovery of 

 its eggs. 



> Proc. Nova Scotian Inst. Scl., vol. 19, 1938, p. 279. 

 210941—53 88 



Figure 266. — Larva (European), just hatched. After 

 Ehrenbaum. 



Figure 267. — Larva, 21.5 mm. Gulf of Maine. 

 Wolffish (Anarhichas lupus). 



The slender transparent larvae of the wolffish 

 of north Europe are described as about half an 

 inch (12 mm.) long at hatching, but those that 

 hatched from a mass of eggs dragged up off Nova 

 Scotia were 17-18 mm. long. 4 They have an 

 enormous baglike yolk sac enclosed in a net of 

 highly developed blood vessels (see fig. 266, p. 

 505) , and thus they suggest salmon or trout larvae 

 remotely, in appearance. Wolffish hatched by 

 Mcintosh and Prince in the aquarium at St. 

 Andrews, Scotland, did not absorb the yolk sac 

 wholly until about 3^ months old and upward of 

 20 mm. long, but in natural surroundings larvae 

 as small as 17 mm. have been found free of yolk, 

 nor was any trace of it visible in the larvae of 21 

 mm. and upward which we have towed in the 

 Gulf of Maine. Larvae of 20 to 22 mm. show the 

 dorsal and anal fin rays in their final number, but 

 the large head, enormous eyes, and tiny teeth, 

 with the fact that there is no definite separation 

 between the anal and dorsal fins and the caudal, 

 give the young fishes an aspect very different from 

 that of their parents until they are 1% to 1% inches 

 long. In life the wolffish is silvery on the sides at 

 this stage, but this metallic hue fades after preser- 

 vation, leaving only the dark brown pigment 

 granules with which the sides are thickly dotted. 

 The largest fry we have seen (44 mm. long) are 

 similarly pigmented but somewhat paler. 



• McKenzie and Homans, Proc. Nova Scotian Inst. Scl., vol. 19, 1938, 



p. 279. 



