PORTLAND, Maine (AP) The federal government has outlined an ambitious, potentially costly new plan to restore populations of Atlantic salmon in the eastern United States.

American rivers once teemed with the salmon, but populations have declined to the point where the last remaining wild populations of Atlantic salmon in the U.S. exist only in a handful of rivers in Maine. The National Oceanic and Atmospheric Administration and U.S. Fish and Wildlife Service are offering a new recovery plan to bring back those fish, which are listed under the Endangered Species Act.

The plan would take decades to fully implement, and focuses on strategies such as dam removals and installations of fish passages.

The estimated cost is about $24 million per year, not including money federal departments already spend on salmon recovery work.