PORTLAND, Ore. (AP) — A judge has refused to block a plan to shoot more than 10,000 double-crested cormorants in the Columbia River estuary.

The plan was released earlier this year by the U.S. Army Corps of Engineers. It wants to stop cormorants from eating millions of baby salmon.

Conservation groups sought a preliminary injunction. They say hydroelectric dams — not cormorants — are the main threat to salmon. The groups filed suit in April against the Corps, the U.S. Fish and Wildlife Service, and the Wildlife Services agency in the U.S. Department of Agriculture.

The Corps said Wildlife Services will manage the killing.

The plan also calls for destroying 26,000 nests on East Sand Island.

The decision came Friday from U.S. District Judge Michael Simon.