SPOKANE, Wash. (AP) — The eggs of endangered Kootenai River white sturgeon in Idaho and Montana are less likely to hatch because of river flow changes caused by Libby Dam and other human actions.

That's according to a new study released this week by the U.S. Geological Survey. The study concluded that sturgeon eggs hatch best in places where rocks are washed clean of algae by river flow.

The report, prepared in cooperation with the Kootenai Tribe of Idaho, examined hatch success in the laboratory on various surfaces, such as clean rocks, algae-covered rocks and sand. Sturgeon eggs settle and adhere to those surfaces in the wild while they develop into larvae. White sturgeon in the Kootenai River were listed as endangered in 1994.