California Department of Fish and Wildlife

Steelhead Trout

Oncorhynchus mykiss irideus

Summer Steelhead Trout (native)

Oncorhynchus mykiss irideus

Summer steelhead have a unique life history pattern, in contrast to other steelhead. Adult summer steelhead enter their natal rivers in the spring or summer, and hold there until winter or spring when they spawn. The majority of adult steelhead enter the river in the fall or winter and spawn in early winter or spring. Along with their vulnerability to poaching, the history of water diversions and other habitat alterations have taken a toll on the runs of summer steelhead. These altered conditions have reduced many runs to critically low numbers and some runs have been eliminated. Steps are being taken to protect these special runs by the Department and other federal and state agencies including protection under the Endangered Species Act.

Coastal Rainbow Trout (native)

Oncorhynchus mykiss irideus

Coastal rainbow trout are usually the first fish that comes to mind when people think of trout in California. From early fish culture programs the rainbow trout has been spread to other continents, making the rainbow well-known around the world. The native range of rainbow trout in California extends along the entire coast and to the Sacramento-San Joaquin system inland. The rainbow's interior range was limited usually by upstream migrational barriers, such as waterfalls and cataracts. Anadromous rainbows, or steelhead trout, spend a portion of their life cycle in the ocean, returning to freshwater streams to spawn. Coastal streams may support both steelhead and freshwater resident rainbows. Due to extensive, widespread stocking, movement, and hybridization, coastal rainbows stocks may have been genetically altered in much of their range. Coastal rainbow trout have been extensively cultured in hatchery programs and selectively bred to produce fish with a variety of characteristics for growth in hatchery environments and "catchability" for anglers.