Five species of Pacific salmon (genus Oncorhynchus) are known from watersheds tributary to the San Francisco Estuary (Estuary), exclusive of the Sacramento and San Joaquin rivers and their tributaries that drain the Central Valley of California (Leidy 2004). Salmon species either historically or recently recorded from Estuary streams include coho salmon (O. kisutch), chinook salmon (O. tshawytscha), chum salmon (O. keta), pink salmon (O. gorbuscha), and the non-anadromous and anadromous life-history forms of rainbow trout (O. mykiss). Recent status reviews indicate that natural populations of coho and chinook salmon and steelhead within coastal California have declined dramatically over the last 50 years, and populations apparently are continuing to decline in other regions. The focus of this report is on the status of rainbow trout.
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