The cormorants watch the sorting of the fish with eager eyes and much repeating of y-eugh, the only word they know. The ayu are not for them, and some of the kajikas and hazés were prizes of science. But zakko (the dace) and haë (the minnow) were made for the cormorant. The boy picks out the chubs and minnows and throws them to one bird and then another. Each catches his share on the fly, swallows it at one gulp, for the ring is off his neck by this time, and then says y-eugh, which means that he likes the fun, and when we are ready will be glad to try again. And no doubt they have tried it many times since, for there are plenty of fishes in the Jewel River, zakko and haë as well as ayu.
Fossil Salmonidæ.—Fossil salmonidæ are rare and known chiefly from detached scales, the bones in this family being very brittle and easily destroyed. Nothing is added to our knowledge of the origin of these fishes from such fossils.
A large fossil trout or salmon, called Rhabdofario lacustris, has been brought from the Pliocene at Catherine's Creek, Idaho. It is known from the skull only. Thaumaturus luxatus, from the Miocene of Bohemia, shows the print of the adipose fin. As already stated (p. [62]), fragments of the hooked jaws of salmon, from pleistocene deposits in Idaho, are in the museum of the University of California.
CHAPTER VI
THE GRAYLING AND THE SMELT
The Grayling, or Thymallidæ.—The small family of Thymallidæ, or grayling, is composed of finely organized fishes allied to the trout, but differing in having the frontal bones meeting on the middle line of the skull, thus excluding the frontals from contact with the supraoccipital. The anterior half of the very high dorsal is made up of unbranched simple rays. There is but one genus, Thymallus, comprising very noble game-fishes characteristic of subarctic streams.
Fig. 80.—Alaska Grayling, Thymallus signifer Richardson. Nulato, Alaska.
The grayling, Thymallus, of Europe, is termed by Saint Ambrose "the flower of fishes." The teeth on the tongue, found in all the trout and salmon, are obsolete in the grayling. The chief distinctive peculiarity of the genus Thymallus is the great development of the dorsal fin, which has more rays (20 to 24) than are found in any of the Salmonidæ, and the fin is also higher. All the species are gaily colored, the dorsal fin especially being marked with purplish or greenish bands and bright rose-colored spots; while the body is mostly purplish gray, often with spots of black. Most of the species rarely exceed a foot in length, but northward they grow larger. Grayling weighing five pounds have been taken in England; and according to Dr. Day they are said in Lapland to reach a weight of eight or nine pounds. The grayling in all countries frequent clear, cold brooks, and rarely, if ever, enter the sea, or even the larger lakes. They congregate in small shoals in the streams, and prefer those which have a succession of pools and shallows, with a sandy or gravelly rather than rocky bottom. The grayling spawns on the shallows in April or May (in England). It is non-migratory in its habits, depositing its ova in the neighborhood of its usual haunts. The ova are far more delicate and easily killed than those of the trout or charr. The grayling and the trout often inhabit the same waters, but not altogether in harmony. It is said that the grayling devours the eggs of the trout. It is certain that the trout feed on the young grayling. As a food-fish, the grayling of course ranks high; and it is beloved by the sportsman. They are considered gamy fishes, although less strong than the brook-trout, and perhaps less wary. The five or six known species of grayling are very closely related, and are doubtless comparatively recent offshoots from a common stock, which has now spread itself widely through the northern regions.
The common grayling of Europe (Thymallus thymallus) is found throughout northern Europe, and as far south as the mountains of Hungary and northern Italy. The name Thymallus was given by the ancients, because the fish, when fresh, was said to have the odor of water-thyme. Grayling belonging to this or other species are found in the waters of Russia and Siberia.