According to the report, the most threatened of California’s native salmonids are the southern steelhead, the winter-run Sacramento River Chinook salmon and the Central California coho salmon. The bull trout, last seen in California in the McCloud River in 1975, is already locally extinct. The coastal rainbow trout, the biologists said, may be California’s only native salmonid to survive for the long haul in any abundance.

The scientists wrote that agricultural demands for river water, population growth and alteration of the San Francisco Bay and Delta ecosystem are major factors affecting salmonids’ long-term survival odds.