The American grayling (Thymallus signifer) is widely distributed in British America and Alaska. In the Yukon it is very abundant, rising readily to the fly. In several streams in northern Michigan, Au Sable River, and Jordan River in the southern peninsula, and Otter Creek near Keweenaw in the northern peninsula, occurs a dwarfish variety or species with shorter and lower dorsal fins, known to anglers as the Michigan grayling (Thymallus tricolor). This form has a longer head, rather smaller scales, and the dorsal fin rather lower than in the northern form (signifer); but the constancy of these characters in specimens from intermediate localities is yet to be proved. Another very similar form, called Thymallus montanus, occurs in the Gallatin, Madison, and other rivers of Western Montana tributary to the Missouri. It is locally still abundant and one of the finest of game-fishes. It is probable that the grayling once had a wider range to the southward than now, and that so far as the waters of the United States are concerned it is tending toward extinction. This tendency is, of course, being accelerated in Michigan by lumbermen and anglers. The colonies of grayling in Michigan and Montana are probably remains of a post-glacial fauna.
Fig. 81.—Michigan Grayling, Thymallus tricolor Cope. Au Sable River, Mich.
The Argentinidæ.—The family of Argentinidæ, or smelt, is very closely related to the Salmonidæ, representing a dwarf series of similar type. The chief essential difference lies in the form of the stomach, which is a blind sac, the two openings near together, and about the second or pyloric opening there are few if any pyloric cæca. In all the Salmonidæ the stomach has the form of a siphon, and about the pylorus there are very many pyloric cæca. The smelt have the adipose fin and the general structure of the salmon. All the species are small in size, and most of them are strictly marine, though some of them ascend the rivers to spawn, just as salmon do, but not going very far. A few kinds become landlocked in ponds. Most of the species are confined to the north temperate zone, and a few sink into the deep seas. All that are sufficiently abundant furnish excellent food, the flesh being extremely delicate and often charged with a fragrant oil easy of digestion.
Fig. 82.—Smelt, Osmerus mordux (Mitchill). Wood's Hole, Mass.
The best-known genus, Osmerus, includes the smelt, or spirling (éperlan), of Europe, and its relatives, all excellent food-fishes, although quickly spoiling in warm weather. Osmerus eperlanus is the European species; Osmerus mordax of our eastern coast is very much like it, as is also the rainbow-smelt, Osmerus dentex of Japan and Alaska. A larger smelt, Osmerus albatrossis, occurs on the coast of Alaska, and a small and feeble one, Osmerus thaleichthys, mixed with other small or delicate fishes, is the whitebait of the San Francisco restaurants. The whitebait of the London epicure is made up of the young of herrings and sprats of different species. The still more delicate whitebait of the Hong Kong hotels is the icefish, Salanx chinensis. Retropinna retropinna, so called from the backward insertion of its dorsal, is the excellent smelt of the rivers of New Zealand. All the other species belong to northern waters. Mesopus, the surf-smelt, has a smaller mouth than Osmerus and inhabits the North Pacific. The California species, Mesopus pretiosus, of Neah Bay has, according to James G. Swan, "the belly covered with a coating of yellow fat which imparts an oily appearance to the water where the fish has been cleansed or washed and makes them the very perfection of pan-fish." This species spawns in late summer along the surf-line. According to Mr. Swan the water seems to be filled with them. "They come in with the flood-tide, and when a wave breaks upon the beach they crowd up into the very foam, and as the surf recedes many will be seen flapping on the sand and shingle, but invariably returning with the undertow to deeper water." The Quilliute Indians of Washington believe that "the first surf-smelts that appear must not be sold or given away to be taken to another place, nor must they be cut transversely, but split open with a mussel-shell."
The surf-smelt is marine, as is also a similar species, Mesopus japonicus, in Japan. Mesopus olidus, the pond-smelt of Alaska, Kamchatka, and Northern Japan, spawns in fresh-water ponds.
Fig. 83.—Eulachon, or Ulchen. Thaleichthys pretiosus Girard. Columbia River. Family Argentinidæ.