Wildlife

Drought pushes endangered California salmon to the brink

Chinook salmon were already endangered in California's Sacramento River, but the record drought parching the western United States has brought the iconic fish even closer to extinction. Chinook, also known as king salmon, need very cold water for their eggs to develop.

If everything goes right, the young salmon hatch and eventually make their way downstream toward the ocean, before later returning to the rivers to spawn and die. But the migration has dropped off in recent years.

There were 4.4 million juvenile Chinook in 2009 – half the number of four years earlier.

Last year, the number of juveniles passing by the dam in Red Bluff, at the northern end of California's Central Valley, was just 411,000.

To date, only 217,000 juveniles have been counted passing through Red Bluff in 2015, versus 280,000 over the same period last year.

The Sacramento Chinook, designated an endangered species in 1994, have been struggling for years, for a number of reasons, but the drought has only exacerbated the problems. Access to the historical spawning habitat of winter-run Chinook salmon on the Sacramento is cut off by the Shasta and Keswick dams, built in the 1940s.