What is a steelhead?

What is a steelhead?

Steelhead are migratory rainbow trout (<em>Oncorhynchus mykiss</em>). Sea-run steelhead migrate between freshwater and the ocean. In the Great Lakes, fish commonly called steelhead live in freshwater lakes and return to tributaries to spawn; they do not migrate to the ocean. Steelhead and rainbow trout are the same species, with different migratory life histories. Anadromy means migration between the sea and freshwater. Great Lakes steelhead remain in freshwater, moving between lakes and tributaries; their lake-run life history should not be described as an ocean migration. They belong to the Pacific salmon genus Oncorhynchus, alongside Chinook, coho, and others. Unlike true Pacific salmon that usually die after spawning, steelhead can survive and return in later seasons (iteroparity), though many Great Lakes fish are harvested or do not make multiple trips. Anglers usually tell a fresh fish by silvery, "steel" flanks that shift toward olive and rainbow coloration after time in the river; a pink to red lateral band that strengthens as the fish colors up; dark spotting on the dorsal fin, adipose fin, and the upper half of the body and tail; and a larger, more elongated shape than resident rainbows of the same age. Great Lakes steelhead are not ocean-going. They use the lakes as the saltwater equivalent — foraging in Lake Erie or Lake Ontario, then ascending tributaries on cooling water and rain pulses. Ohio stocking records list changing strain mixes by year. Other jurisdictions mix stocked and wild reproduction depending on the watershed.