Snake blenny Lumpenus lumpretaeformis (Walbaum) 1792

SERPENT BLENNY

Description—

This is a very slender little fish as its name implies, being only about one-twentieth as deep as it is long, slightly flattened sidewise, with head about one-eighth as long as body to base of caudal fin, large eyes, wide mouth, and blunt snout. It somewhat suggests a launce (p. 488) in general form, but is much more slender and eel-like. Also, its rounded tail (that of the launce is forked), its large pectoral fins, spiny dorsal fin (the launce has a soft dorsal only), and [page 495] the fact that its lower jaw does not project beyond the upper, together with its color, serve to separate it from the launce at a glance.

The chief anatomic feature (apart from its slenderness) distinguishing it from the rock eel (p. 492) is that the ventral fins (each of one short spine and three longer rays) are well developed and one-third to one-half as long as the pectorals, slightly in advance of which they stand. The pectorals, too, are much larger than those of the rock eel, and its dorsal fin, with 68 to 85 spines and its anal with 49 to 62 rays are fully twice as high, relative to the depth of the body, while its anal fin originates farther forward; the separation of dorsal and anal fins from the caudal is more evident; and its eyes are noticeably larger.

The very slender body is the most obvious difference between this species and its allies the shanny (p. 497), the Arctic shanny (p. 497), and the radiated shanny (p. 498), which are rather robust. The outline of the caudal fin, which is oval (more pointed in large fish than in small), with the central rays much longer than the outer ones, is diagnostic, too.

Color—

Whitish or pale brown on the back and sides, with darker brown markings. On a 12 inch fish taken off the coast of Maine the head was pale brown, the sides of the body blotched with brown, the dorsal fin marked obliquely with 18 pale bars, the caudal marked transversely with 8 bars, the anal rays pale brown against a colorless membrane, the ventrals white, and the pectorals tinged with brown.

Size—

The largest one so far measured was 19 inches long.^[64]

Remarks—

Vladykov's^[65] discovery that Newfoundland specimens have a larger number of dorsal fin-spines (85) and anal fin rays (62) and a longer caudal fin (longer than the head) than others from the St. Lawrence estuary (75-79 dorsal spines, 52-56 anal rays) shows that the snake blenny tends to break up into local races. Vladykov has made the St. Lawrence race the basis of one new subspecies, americanus, and the Newfoundland race the basis of another, terrae novae; both of which have more spines and rays than have been recorded for some eastern Atlantic specimens. Gulf of Maine specimens, with 77-83 dorsal spines, and 56-59 anal rays, are intermediate between the Newfoundland and Gulf of St. Lawrence races in this respect.

Habits—

Little is known of the habits of the snake blenny on either side of the Atlantic. Although it is not found along the littoral zone, it is a fish of comparatively shoal water, never taken as deep as 100 fathoms (so far as we have been able to learn) and apparently the most common from a fathom or so below tide mark down to 40 or 50 fathoms. And as most of the specimens that have been caught in Scottish waters were picked up by the foot rope of the trawl, Sim's^[66] suggestion that it burrows in mud [page 496] or clay bottom probably is correct. The Albatross II has taken it both on mud bottom and on hard.

Food—

Amphipods, copepods, and other tiny crustacea, with very small starfish, small bivalves, and holothurians have all been found in snake blenny stomachs in British seas. These blennies are eaten in their turn by large fish, by cod and halibut, for example, in Massachusetts Bay,^[67] by pollock in the Bay of Fundy; and by cod in Northumberland Strait, Gulf of St. Lawrence, as Capt. Thor Iversen informed Dr. Huntsman from his experience during the Canadian Fisheries Expedition of 1915.

The spawning season has been stated as autumn or winter in north Scandinavian seas, and it may commence by late summer there, or by early autumn, for Sim found its roe well advanced in development as early in the season as the end of April. Its drifting larvae have been taken in tow nets from February to March in the Baltic, and from March to May in the Gulf of Maine.

The eggs of this species have not been seen, but they probably sink and stick together like those of the rock eel. Apparently the larvae are of considerable size at hatching, for the smallest we have taken (the smallest on record) were about 11 mm. long, though they still lacked any trace of the dorsal- and anal-fin rays. Snake blenny larvae are very slender, resembling the corresponding stages of the rock eel and of the launce in general appearance, but they are distinguishable from both of these by the fact that the vent is situated considerably in front of the midlength of the trunk. There is no danger of confusing them with the young of the herring, the only other very slender pelagic fish larva (besides rock eel and launce) that is apt to be found in any numbers in the Gulf of Maine in spring, for the tail of the herring is forked from a very early stage and its vent is situated much farther back than that of the blenny (p. 91). Another distinctive feature of the snake blenny larvae is the presence of a large black pigment dot at the base of each pectoral fin, and of a double row of 6 to 9 black dots along the dorsal surface of the intestine with several about the vent, which are very conspicuous by contrast with the colorless body. Our largest pelagic larva (41 mm. long) showed most of the characters of the adult, although it was transparent and had the arrangement of pigment characteristic of the earlier larval stages.

General range—

Arctic and northern Atlantic Ocean; south to Scotland, the Baltic, and the southern part of the North Sea in the eastern side; to the offing of southern New England in the western side.

Occurrence in the Gulf of Maine—

It is probable that this northern fish occurs in small numbers around the coastline of the Gulf at some little depth. Thus Huntsman reports it from St. Mary Bay, Nova Scotia, in August and September; from Passamaquoddy Bay from April to August; and in the open waters of the Bay of Fundy from January on. It was recorded off Eastport in 1872; Albatross II trawled one specimen (about 12 inches long) 3 miles south of Great Duck Island, near Mount Desert, Maine, in 28 to 33 fathoms, April 1927; two others (8 and 8¼ inches long) 13 miles east of Boone Island, in 88 fathoms in August 1928; one off the Isles of Shoals at 72-78 fathoms in August 1926; one at 42 fathoms on the eastern slope of Stellwagen Bank, about 17 miles off Cape Ann in July 1931. And Goode and Bean^[68] described it long ago as a common resident in the deeper parts of Massachusetts Bay.

Our tow nettings, also, of 1920 yielded its drifting larvae off Seguin Island; near Cape Elizabeth; over Platts Bank; near the Isles of Shoals; off Ipswich Bay; off Cape Ann; off Boston Harbor; and in the southwest basin of the Gulf off Cape Cod during March, April, and May evidence that it breeds successfully throughout the southern part of its range. While it has not been reported on Browns or Georges banks, it is to be expected there.

It has never been reported from the banks along the outer coast of Nova Scotia, so far as we know. But it is so slender and active a fish that it can easily pass through the meshes of any of the nets that are used in our Gulf by commercial fishermen, hence is not likely to be brought in unless it is sought for especially. And the experimental trawlings by the Newfoundland Fishery Research Laboratory did take it at several stations on the Newfoundland Banks, as well as in the Gulf of St. Lawrence, and also off the southeastern coast of Labrador, while it has long been known from [page 497] as far north on the Labrador coast as Ungava Bay.^[69]