GRANTS PASS — Scientists think toxins from a blue-green algae plaguing lakes and rivers around the West are harming an endangered fish in the Klamath Basin, adding another obstacle to restoring species that have forced irrigation shut-offs for farmers.

U.S. Geological Survey fish biologist Scott VanderKooi said Wednesday that liver damage detected in young Lost River and shortnose suckers in Upper Klamath Lake appears to have been caused by the algae known as microsystin.

He says more research is needed to say the toxin is actually in the fish.

The lake is the main irrigation reservoir for more than 1,000 farms in the upper Klamath Basin. A drought in 2001 forced irrigation cutbacks to keep enough water in the lake for the endangered fish.