The chum salmon is the second largest of the Pacific salmon; they have been recorded up to 33 pounds, although the average weight is 10 to 15 pounds.
Because of the large and fearsome-looking canine teeth the chum salmon develops during spawning runs, the name dog salmon is often applied. Oncorhynchus means hooked snout; keta is the Russian name for this fish.
The body is elongate, somewhat compressed, depth about 3.8 into standard length, and deepest behind tip of pectoral fin. The head is conical with head length about 4.4 into standard length. Mouth is terminal, large, and directed upward. The upper jaw reaches almost to the posterior margin of the orbit. Snout is narrowly rounded in profile (in spawning males the snout is greatly enlarged and hooked). Lips are fleshy with well developed teeth in both jaws, on the head and shaft of the vomer, palatines, and tongue. There are no teeth on the basibranchials. Teeth in both jaws become large and canine (fang-like) in spawning males (hence the vernacular name of dog salmon).
Interorbital space is high, wide, convex, rounded, its width about 2.6 into head length. Eye diameter is about 6.7 into head length. Gill membranes are free of each other and of the isthmus. The first gill arch has from 18 to 26 smooth and widely spaced gill rakers. Caudal peduncle is moderately compressed, rather slender, its least depth about 14 into standard length. Pyloric caecae count is about 140. Scales are cycloid with 130 to 153 scales above the lateral line, and 126 to 151 on the lateral line.
Adipose fin is small, slender, and fleshy. The number of rays in each of the fins are: dorsal, 10-13; anal, 13-17; pectorals, about 16; and, pelvics , about 10 (each of the abdominal fins have a free tipped fleshy appendage above its insertion). The caudal fin is slightly forked.
In spawning males the upper jaw forms an elongated hooked snout and the teeth are enlarged. In spawning females the upper jaw is not strongly hooked
Chum salmon are not well distributed along the West Coast. California, Oregon, and Washington have some small runs in a few streams and rivers, but the only state which has large chum runs is Alaska, where chum are an extremely important commercial fish and provide a limited but growing sport fishery. Their southern range extends as far south as the San Lorenzo River in California, and ocean catches have been made as far south as Del Mar, California. Chum occur as far north as north eastern Asia and in north western North America from the Mackenzie River in Canada to the Aleutian Islands. California still has remnant chum spawning runs in a few tributaries of the Sacramento River; a few chum are found in the Klamath River at times as well. Other north western runs of chum salmon are found in the Tillamook Bay drainage of Oregon, the Kilchis River, and several other coastal rivers, especially where private salmon ranches have released them. Most of the very small commercial catch of chum from California’s coastal waters originate from streams farther north, primarily in Alaska. This is probably true of much of Oregon’s commercial chum catch, as well. In Alaska, however, chum are considered third in value of all Pacific salmon, such is the strength of their runs. In some rivers chum salmon have both a summer and a fall run. The summer run chum tends to average smaller in size and generally spawns closer to the estuary – sometimes in it if estuary streams are present – than does the fall run, The nor- mal life cycle is 3 to 5 years, but 2 year cycles are also en- countered.