Wolffish Anarhichas lupus Linnaeus 1758

CATFISH; OCEAN WHITEFISH

Description—

The wolffish suggests a huge blenny in its general make-up, except that its dorsal fin spines are flexible at their tips instead of stiff; that it has no ventral fins; and that its mouth is armed with a set of teeth more formidable than those of any other Gulf of Maine fishes, except for its relative, the spotted wolffish (p. 507), and for some of the sharks. There is a row of about 6 very large, stout, conical canine tusks with a cluster of 5 or 6 smaller canines behind them in the upper jaw; and the roof of the mouth back of the latter is armed with three series of crushing teeth. The central series of these consists of a double row of about 4 pairs of large rounded molars that are united into a solid plate; each of the outer series consists of two alternating rows of blunt conical teeth. In the common wolffish the central series, which is the longest of the three, originates a very little in advance of the outer series, and it extends rearward noticeably farther. The lower jaw has 4 to 6 large tusks in front, behind which are two longitudinal diverging rows of rounded molars. And the throat also is armed with small scattered teeth. The great projecting tusks, rounded nose, and small eyes give the wolf a singularly savage aspect.

The body is deepest close behind the head, tapering back to a slender caudal peduncle and to a small weak tail fin. The dorsal fin (69-77 spines) is about half as high as the head is long and uniform in height from end to end except for its rounded corners, and it extends from the nape of the neck to the base of the caudal fin. The anal fin (42-48 rays) is only about half as high as the dorsal, and a little more than half as long; its rear corner is angular. The pectoral fins are large and rounded, and the caudal fin is slightly convex in outline.

Color—

Wolffishes are dull-colored, but they vary widely in tint. The upper parts and the dorsal fins of those taken off the Massachusetts coast have been described as purplish brown and we have seen them of this tint. But fish caught on Georges Bank are invariably dull olive green, according to Mr. Clapp, while they are described as purplish, brownish, or bluish gray, or slate colored in other seas. No doubt the color of the wolf, like that of many other ground fish, varies with that of its surroundings, purplish and brown tints ruling among red seaweeds and olive gray on clean bottom. Whatever its tint, its sides are transversely barred with a variable number (usually 10 or more) of irregular and broken [page 504] darker bands or blotches, or scattered spots, that extend out on the dorsal fin. The throat and the belly back to the vent are dirty-white tinged with the general ground tint of the upper parts. Wolffish fade so soon after they are caught that those seen in the markets usually are much paler than they were in life.

Size—

A length of 5 feet seems about the maximum in Gulf of Maine waters; one more than 4 feet long is seldom seen, and the larger fish caught and brought in run less than 3 feet. European authors speak of wolffish of 6 feet and even longer, but they average only about 2 feet in Scandinavian waters,^[95] i. e., scarcely so large as those in the Gulf of Maine. A fish 33 inches long weighs about 10 pounds, one of 37 inches between 16 and 17 pounds. The greatest weight reported for American waters so far is about 40 pounds.^[96]

Habits—

The wolffish is solitary, living one here and one there, and it is not abundant anywhere, in the sense that this term can be applied to the cod, to the haddock, to the pollock, or others of our commercially important fishes. It holds close to the bottom; and it is always caught on hard ground, never on mud, a preference illustrated by the fact that our experimental trawlings on the soft bottom of the deep troughs within the Gulf did not catch one wolffish, though they did yield a variety of other fishes in plenty.^[97] It is a weak swimmer, moving by sinuous side to side undulations like a blenny or an eel; and probably it spends most of its life hidden among seaweed or rocks, or nosing about such surroundings for food. There is no reason to suppose that it ever attacks other fish in its normal way of life, but when hauled out of the water it snaps like a bulldog and with good aim at anything in its way, the hands, an oar, or at other fish among which it is thrown, and it can inflict a serious bite. Goode^[98] remarks that it has been known to make a furious attack on persons wading among the rock pools at Eastport, Maine.

The depth zone occupied by the wolffish at one time or another extends from a fathom or so below tide mark down to 85 fathoms at least, and very likely deeper. It has been reported in tide pools at Eastport, but we have never heard of it in such situations or at low-water mark anywhere else in the Gulf, nor does it run up estuaries, and it is probable that most of the local stock lives in depths of 10 to 50 or 60 fathoms.

The wolffish is a cool- and cold-water fish, as might be assumed from the fact that its regular geographic range extends hardly farther west than Cape Cod and Nantucket shoals. Those living in the coastal belt of our Gulf, at depths of 25 fathoms or less, regularly experience temperatures as low as 34°-36° (locally even as low as 32°) at the end of the winter, or at some time during the spring, according to locality.^[99] They are in temperatures equally low or even lower, fractionally, in late spring and early summer on the fishing grounds along outer Nova Scotia, while the grounds where they are caught in the Gulf of St. Lawrence are flooded every spring and early summer, with water as cold as 32°, which they can avoid only by descending deeper into the Laurentian Trough, a movement of which we have no direct evidence. And they have been caught, widespread, on the Newfoundland Banks (p. 507) in water as cold as 30°-31°. At the other extreme, the highest temperature in which wolffish occur in any numbers is about 50°-52°, at the end of summer (again for those living shoalest) in the coastal belt of our Gulf, and also on the Nantucket shoals grounds. They are never known to run up into brackish water.

The wolffish is resident wherever it is found, to be caught throughout the year. For example, about as many are brought in from Georges Bank in one month as in another, allowance being made for the difficulties and dangers of winter fishing. And as it passes through only a brief pelagic stage when it is young (p. 506), it is a comparatively stationary fish, with much less interchange from one locality to another than is the case with cod or with haddock.

The diet of the wolffish consists wholly of hard-shelled mollusks, crustaceans, and echinoderms. So far as we can learn fish have never been found in the stomach of a wolffish. Mr. Clapp found that the 50 or 60 fish that he opened on Georges Bank had all eaten large whelks (Buccinum), cockles (Polynices, Chrysodomus and Sipho), sea clams (Mactra), and other shellfish, which it crushes easily in its viselike molars. Sometimes, [page 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 observations 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 apparently 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 duration 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.

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 31/2 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 11/4 to 13/4 inches long. In life the wolffish is silvery on the sides at this stage, but this metallic hue fades after preservation, 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.

[page 506]

When first hatched, the larvae lie on bottom like young trout or salmon, resting on the yolk; it is not until the latter is considerably reduced in size (several weeks after hatching) that they swim much. And they do no more than dart upward for a few inches and then settle back again until a month old. Thus the wolffish spends the early part of its life close to bottom instead of drifting at the mercy of tide and current, as all fishes do that produce buoyant eggs. Some of the older larvae and the young fry adopt a drifting habit for a time after the yolk is absorbed (we took some 20 specimens of various lengths from 21 to 44 mm., in our tow nets during March and April 1920). But it seems that they seldom rise to the uppermost water layers, for only 2 of the 8 hauls that took them were made at the surface, the others were at depths of 30 to 60 fathoms. And as fry no larger than this have been trawled on bottom in European waters, it seems that some do not leave the ground. It follows, then that the wolffish probably is not subject to the long involuntary migrations that are carried out by most of the members of the cod and flatfish tribes, but that it passes through its entire larval stage near where it is hatched, hence localities where the young are taken are evidence of local spawning. The brevity of the pelagic stage, if any, also implies that the stock of wolffish in any given locality depends on local reproduction for its maintenance.

In Scottish waters wolffish fry have been taken as long as 5 to 6 inches in July, and up to 7 to 8 inches in August, pointing to a rapid rate of growth for the first summer. Nothing is known of the later growth.

General range—

Both sides of the North Atlantic; north to Davis Strait in American waters; south regularly to Cape Cod; less often to the westward along southern New England, and exceptionally to New Jersey;^[5] also Greenland; Iceland; and northern Europe southward to northern France.

Occurrence in the Gulf of Maine—

Although the wolffish has been recorded at only a few stations in the Gulf in scientific literature^[6] it is a fairly common fish, to be caught on suitable bottom in all parts of the Gulf, though nowhere in any great numbers. Thus, something like 30,000 pounds were taken off western Nova Scotia yearly during the period 1944-1946;^[7] scattering fish are caught at the mouth of the Bay of Fundy and around Grand Manan (stray fish only up the Bay, if any); on one occasion, in April 1930, we saw 35 of them, 2 to 3 feet long, caught on one set of a long line in 18 fathoms of water off Mount Desert Island; and enough are caught on the small grounds thence eastward to Eastport for 16,000 pounds to have been reported from this statistical area in 1945. The various small coastwise fishing grounds, westward from Mt. Desert, yield much greater numbers, as reflected in reported landings, for 1945, of 253,000 pounds for central Maine; about 1,400 pounds for Cashes Ledge and the neighboring patches of hard bottom, where we have caught them, as we have on Platts Bank also; about 26,000 pounds for western Maine; and about 118,000 pounds reported as taken by the vessel fishery off the coast of Massachusetts from the New Hampshire line to Cape Cod.

Recent statistical surveys have not been of a sort to localize the catches more precisely than this. But the small-boat fishermen, landed more than 37,000 pounds in Essex County, Mass., in 1905, mostly from Jeffreys Ledge, from Stellwagen Bank, and from the deeper rocky spots near Gloucester and Nahant, grounds where fishermen report them as fairly plentiful. And there is no reason to suppose that the situation in this respect has altered subsequently.

Considerable catches are also brought in from Cape Cod waters, as reflected in landings of 233,000 pounds reported for Barnstable County in 1945, about 224,000 pounds for Cape Cod in 1947.^[8]

Wolffish are not taken in commercial quantities either to the westward of Nantucket Shoals, or [page 507] on the southwestern part of Georges Bank.^[9] But the so-called "south channel" grounds from Cape Cod out to the northwestern part of Georges, with the northern and eastern parts of Georges, and Browns Bank to the eastward, support so large a population that these grounds, combined, yielded about 368,000 pounds in 1945, about 840,000 pounds in 1947.^[10] And it is much more likely that the differences from year to year in the catch^[11] are due to the fact that wolffish are taken only incidentally, so that the catch depends on the precise grounds fished, rather than on any periodic alterations in their abundance.

In 1946 (most recent year for which we have seen statistics for the Canadian as well as for the United States catches) something like 1,571,500 pounds of wolffish were reported as caught within the limits of our Gulf, or something like 260,000 to 270,000 fish, assuming an average weight of 5 to 7 pounds. But it is anyone's guess what proportion of the total population this may be.

Wolffish appear to be about as numerous on the various fishing grounds along outer Nova Scotia (reported catch for 1949, about 800,000 pounds) as they are on Georges and Browns Banks. (p. 507). But while they are reported at several localities in the southern side of the Gulf of St. Lawrence,^[12] also off the west coast of Newfoundland, and at Anticosti, they are not plentiful enough anywhere in the Gulf to yield commercial catches.^[13] And this applies equally to the Newfoundland Banks, though they have been taken widespread there; also along the south and southeast coast of Newfoundland, and as far north as the offing of Hamilton Inlet on the outer Labrador coast, during the experimental trawlings carried out by the Fishery Research Board of Newfoundland.

The fact that we have taken wolffish larvae in the channel between Browns Bank and Cape Sable; near Seal Island (Nova Scotia); on German Bank and off its slope; off Lurcher Shoal; off Machias (Maine); on Jeffreys Bank (off Penobscot Bay); and in Massachusetts Bay a few miles off Gloucester, is evidence that the wolffish breeds in the Gulf wherever it is to be found, as might, indeed, be expected. And this applies, equally (it seems) to the more northern parts of the American range of the wolffish, for its pelagic young have been reported off northeastern Newfoundland; in the Strait of Belle Isle; and off Sandwich Bay on the Atlantic coast of Labrador, by the Newfoundland Fisheries Research Commission.

Commercial importance—

The market demand for wolffish is of comparatively recent growth. It is an excellent table fish, selling readily as "ocean catfish" or as "whitefish." In 1947 the average price to the fisherman was between 4 and 5 cents per pound, and the Gulf of Maine catch was worth about $70,000 to $80,000.