LEWISTON, Idaho -- A vital food source the struggling southern resident orcas depend on is predicted to be in short supply.
An early forecast by fisheries managers in Idaho suggests a poor outlook for the upcoming chinook salmon season there.
A group of federal, state and tribal fisheries managers is predicting that just over 48,000 spring chinook are expected to return to the mouth of the Snake River. Only about 8,200 of those are predicted to be wild salmon.
In 2018, more than 100,000 Snake River chinook were expected to return. Only about 67,000 did.
Spring and summer chinook are an important food source for the orca. In the first few months of the year, the southern resident orca can be found at the mouth of the Columbia River to feast on chinook as the salmon migrate upstream to spawn.
Historically, adult salmon returns to the Columbia Basin were believed to be between 10 and 16 million fish per year.
There are only 75 southern resident orcas left.
The group's report claims adult salmon returning in 2019 were exposed to ocean conditions that "may have been unfavorable for salmon survival." A number of ocean indicators - such as sea-surface temperature and plankton abundance - were detrimental to salmon survival, according to the report.