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Inconnu
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The inconnu is a large, coarse salmonid inhabiting the larger streams of Alaska and northwestern British America. It is known from the Yukon and Mackenzie rivers, and the tributaries of the latter below the cascades; locally abundant and reaching a large size, usually 5 to 15 pounds, but sometimes 30 to 40 pounds. Its large size and comparative abundance render the inconnu of considerable commercial importance, especially in the Yukon since the great development of the gold-fields of that region. Little or nothing is known of the habits of this species.
Head 4 5/6; eye 6; D. 12; A. 14; scales 100; gillrakers 7+17. Eye less than snout, nearly equalling the narrow interorbital; maxillary reaching the vertical of posterior edge of pupil, its length very slightly more than 1/3 head; supplemental bone long and narrow, nearly as wide as the maxillary, the anterior end notched, the angle above the notch sharply pointed, the lower angle bluntly rounded; the gillraker in the angle very stiff and bony.
GENUS ONCORHYNCHUS SUCKLEY
The Pacific Salmon
Body rather long, subfusiform, and compressed; mouth wide, the maxillary long, lanceolate, usually extending beyond the eye; jaws with moderate teeth, which become in the adult male enormously enlarged in front during the spawning season; vomer long and narrow, flat, with a series of teeth both on the head and the shaft, the latter series comparatively short and weak; palatines with a series of teeth; tongue with a marginal series on each side; teeth on vomer and tongue often lost with age; no teeth on hyoid bone; anal fin comparatively long, of 14 to 20 rays; pyloric coeca very numerous; gillrakers numerous; ova large and comparatively few. Sexual peculiarities very strongly developed, the snout in the adult males greatly distorted during the breeding season, the premaxillaries prolonged, hooking over the lower jaw, which in turn is greatly elongate and somewhat hooked at the tip; the body becomes deep and compressed, a fleshy hump is developed before the dorsal fin, and the scales become embedded in the flesh, and the flesh, which is red and rich in the spring, becomes dry and poor.
The American species of this genus, 5 in number, are mostly salmon of large size, ascending the rivers tributary to the North Pacific in America and Asia. The genus is very close to Salmo, differing chiefly in the increased number of anal rays.
Concerning the habits and distribution of the salmon we quote (with such modifications as later observations necessitate) the following, based upon investigations made by Jordan, Evermann, and Gilbert.
Of the species of Oncorhynchus, the blueback (O. nerka) predominates in Fraser River and in the Yukon River, the silver salmon (O. kisutch) in Puget Sound, the quinnat (O. tschawytscha) in the Columbia and the Sacramento, and the dog salmon in most of the streams along the coast. All the species have been seen by us in the Columbia and Fraser River; all but the blueback in the Sacramento, and all in waters tributary to Puget Sound. Only the quinnat or king salmon has been noticed south of San Francisco. Its range has been traced as far as Ventura River. Of these species, the king salmon and blueback salmon habitually "run" in the spring, the others in the fall. The usual order of running in the rivers is as follows: nerka, tschawytscha, kisutch, gorbuscha, keta. According to early authors, the tschawytscha precedes nerka in Kamchatka.
The economic value of the spring-running salmon is far greater than that of the other species, because they can be captured in numbers when at their best, while the others are usually taken only after deterioration. To this fact the worthlessness of Oncorhynchus keta, as compared with the other species, is probably chiefly due.