The science of the sucker fish is still not well understood, and the coho salmon downstream are unquestionably under pressure.
Smaller salmon also found the Elwha to their liking, and coho, steelhead, sockeye and other fish once numbered close to half a million: until, that is, two dams were built across the river in 1913 and 1924.
The unfinished structure is getting in the way of the dwindling population of endangered coho salmon and steelhead which want to swim up the Rogue river.
The oceanic prairie has been sectioned and buffalo have been replaced by cattle and slaughter-houses; the coho salmon that Lewis sketched with such interest is nearly extinct in the rivers where the expedition found it in abundance.
Another officially endangered species, the coho salmon, spawns in the Klamath river.
The coho also favours the larger rivers.
The coho may weigh up to 16 kg (35 pounds) and is recognized by the small spots on the back and upper tail-fin lobe.
The introduction of Pacific coho and chinook salmon and other game fish into Lake Michigan, however, met with surprising success and caused a boom in the sportfishing industry, which now surpasses commercial fishing in economic importance.
Five species pink, chum, coho, sockeye, and chinook are found in the streams draining the mountains, each with its own distinctive range and environmental conditions.
The restocking of lake trout and the introduction of coho salmon have rejuvenated recreational and commercial fishing on the lake while also greatly reducing the population of alewives (small saltwater fish that entered the Great Lakes via the St .Lawrence Seaway and created many problems when large numbers died off in springtime).
The deep, cold waters of Lake Superior contain lake trout, whitefish, coho and chinook salmon, steelhead, smelt, herring, and ciscoes.
