Radiated shanny Ulvaria subbifurcata (Storer) 1839

Description^[79]—

The most conspicuous feature of this little fish, and one that sets it apart from all the other blennies of our Gulf, is that the forward part of its dorsal fin is marked with a [page 499] single large dark blotch. More significant morphological characters are that it is much stouter of body (about one-sixth to one-seventh as deep as it is long) than the snake blenny; that its pectoral fins and especially its ventrals are considerably larger, relatively, than those of the rock eel (p. 492), while its ventrals are situated farther in advance of the pectorals; and that its gill openings are much wider and extend forward under the throat (confined to the sides of the neck in the rock eel). The evenly rounded outline of its pectorals distinguishes it from the shanny, in which the lower rays are the longest, and are separate at their tips. It is a stouter fish than the Arctic shanny (p. 497), and its lateral line is double, with an upper branch and a lower, whereas the lateral line of the Arctic shanny is single. The outline of the edge of its gill covers, with the upper corner terminating in a rounded fleshy flap concealing a sharp angle, is diagnostic also, for they are rounded in all the other Gulf of Maine blennies.

The dorsal profile of the head is more convex than the ventral; the lower branch of the lateral line runs the whole length of the body, but the upper branch (the more obvious of the two) reaches only about as far back as the tips of the pectoral fins. The dorsal fin, of 43 or 44 spines, is higher, relatively, than that of the rock eel, and is practically continuous with the caudal fin. The anal fin, of about 30 rays, is about half as long as the dorsal, and it is separated from the caudal by a short but definite interspace, made obvious by the abrupt rear angle of the anal. The pectoral fins, evenly rounded in outline, reach back about as far as the eighth dorsal-fin spine. The rear margin of the caudal fin is evenly rounded.

Color—

The most distinctive feature of the color pattern, one which marks this species among local blennies, is the presence of a large oval dusky blotch on the dorsal fin extending from the fifth or sixth spine to the eighth or tenth spine. The back and the upper parts of the sides are dull brown, obscurely barred or blotched alternately with paler and darker; the sides of the head are marked with a dark bar running obliquely downward and backward from the eye; and the belly is pale brownish (described also as yellowish white). The caudal fin is crossbarred with 3 or 4 series of dark dots, and the dorsal fin is marked with many tiny dark dots, besides the blotch just mentioned.

Size—

The largest one we have seen or read of is 6½ inches long, but the maximum size may well be larger.

Habits—

Nothing is known of the mode of life of this shanny except that it is a bottom fish like other blennies, living among seaweed and stones from low-tide mark down at least to 30 fathoms, and very likely much deeper. Dr. Huntsman writes in his notes, "It is found under stones near low tide mark" with the rock eel but far less abundantly than the latter and only on the more exposed shores. Cornish^[80] likewise describes it as taken under stones on the beach, as well as in the dredge and trawl in 6 to 30 fathoms at Canso, Nova Scotia.

The eggs have not been seen, but the fact that we have taken larvae as small as 8 to 11 mm. in our tow nets in June, July, and October^[81] points to a spawning season lasting from late spring throughout the summer (if our identification is correct).

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General range—

So far this fish is known only off the boreal coasts of eastern North America, from eastern Newfoundland, the north shore of the Gulf of St. Lawrence,^[82] and from northern Nova Scotia to Nantucket Shoals and southern Massachusetts.^[83]

Occurrence in the Gulf of Maine—

This shanny, first described by Storer from a specimen found at an unusually low tide among the seaweed at Nahant on the north shore of Massachusetts Bay in 1838, was long supposed to be rare. But it has proved to be common in the Bay of Fundy^[84] among seaweed on rocky shores, a number having been taken both at Campobello Island and at Crand Manan, and one in the mouth of the St. Croix River, while the Museum of Comparative Zoology has a specimen from Grand Manan, collected by Verrill many years ago. Huntsman also reports it from St. Mary Bay on the Nova Scotia shore, and we have found several in the tide pools at Nahant, on the northern shore of Massachusetts Bay. Offshore, we have trawled it near Seguin Island; in Massachusetts Bay; also on the eastern part of Georges Bank. And we have found so many in the stomachs of cod caught on Nantucket Shoals, on Cashes Ledge, and on other offshore grounds as to show that it is widespread in the Gulf on hard bottom, from the shore down to at least 30 fathoms, while we have had one from as deep as 45 fathoms. Our tow nets also have taken its pelagic larvae near Seal Island (Nova Scotia); in the Grand Manan Channel; at the mouth of Casco Bay; near Cape Porpoise; off the Isles of Shoals; near Cape Ann; and in Massachusetts Bay.

The only importance of this little fish in the natural economy of our Gulf is that many of them are eaten by cod and by other fishes.