Oncorhynchus keta

Author: (Walbaum, 1792)

Oncorhynchus keta (Walbaum, 1792)

Status in World Register of Marine Species:
Accepted name: Oncorhynchus keta (Walbaum, 1792) (updated 2009-06-25)

Diagnosis: elongate, becoming deeper with age, spawning males becoming slightly hump- backed. Tip of upper jaw reaching to somewhat behind eye; snout and lower jaw becoming somewhat hooked in spawning males (less so than in O. gorbuscha). Gillrakers 19-25. Pyloric caeca numerous, 135-185. Dorsal finrays iii-iv 9-11, and an adipose fin behind it; pelvic finrays i-ii 8-11, base below about middle of dorsal fin; anal finrays iii 12-15; caudal fin slightly forked, scales small, 125-150 in lateral line. Vertebrae 69-71. Colour: bright silvery with no distinct black spots; spawning males dark olive, flanks reddish grey with crimson or lilac bars, females less distinctly marked. Size: to 100 cm and 4.9 kg, usually 60-75 cm.

Habitat: pelagic at 0-50 m, but deeper in winter, forming dense shoals during spawning run and making considerable migrations; juveniles in mouths of rivers and bays. Food: fishes (herring, sand eels, smelt), also crustaceans; young at sea on crustaceans (harpacticoids, calanids, amphipods); in freshwater, adults do not feed. Reproduction: summer population enters rivers early July to late August, spawning from mid-August; autumn population enters rivers from mid-August, spawning from mid-September at 2-8 years old (usually 3-4); adults die after spawning; rarely migrate far, except up large rivers; fry soon descend, forming shoals in estuarine areas and often remaining near the shore for several months and at sea for 3-5 years.

Distribution: autumn populations from Pacific introduced into rivers affluent to White and Barents Seas (1930-45, 1957-62), but maturation too late in year (September - October) and none have survived; planting of summer populations will be attempted in the future.

Eggs, larvae and young stages. Disler, 1953: 354, fig. 1-9; 1957: 9-15, fig. A-G (col.), 1-16 | Soin, 1956: 1364, fig. 1(2), 2 (1) | Mahon and Hoar, 1956: 1, pl. 1-8 (fig. 1-84).
Otoliths (sagitta). No data.