An unusually low kokanee salmon spawning run on a Lake Tahoe tributary has wildlife biologists concerned about the effect on bald eagles and other species that feed on the fish.
Only an estimated 2,000 kokanee have made the run up Taylor Creek on the lake's south shore this fall, down from the usual 40,000 to 80,000 salmon. It's the lowest number since the mid-1980s.
"One season is not going to make a huge difference," U.S. Forest Service biologist Raul Sanchez told the Tahoe Daily Tribune. "The eagles know the fish are here, but it may catch on over time that if there are less fish, (the eagles) may or may not come back."
The Forest Service has found 10 of California's estimated 480 bald eagles in the Tahoe Basin - mostly on the south shore. Four are believed to remain year-round, and the rest are migratory.
Each fall, adult kokanee salmon return to Taylor Creek - two to four years after they were spawned - to mate, lay their eggs and die.
They leave behind eggs that hatch about 100 days later. The new stock remain in the creek over the winter and then swim downstream to Lake Tahoe in the spring.
Once it begins, the salmon run lasts about a month. The dead fish provide food for bald eagles, gulls, raccoons and other wildlife.
Warm weather, which has kept water temperatures unusually high, is being eyed as a factor in the low salmon run.
The Forest Service released more water from Fallen Leaf Lake this week to boost kokanee numbers, but it proved unsuccessful.
"We could have a run at the end of October, but I doubt it," wildlife biologist Jeff Reiner said.
Researchers said they'll consider seeking grant money to study the problem.
"It appears to be a small run. But our biggest concern is whatever it is that caused this low run might be a continuing problem," said fisheries biologist Brent Allen of the Tahoe Research Group.
"It usually takes something like this to get the funding," he added.
The fish is a nonnative species at Tahoe.