BOISE, Idaho (AP) — Federal officials say changes in how dams on the Snake and Columbia rivers are operated are needed to improve migratory conditions for protected runs of Snake River chinook salmon and steelhead.

A proposed recovery plan released Thursday by the National Marine Fisheries Service also says habitat needs to be improved in tributaries where fish spawn and in the Columbia River estuary where young fish transition to ocean life.

Officials say the Snake River and its tributaries in Idaho, Oregon and Washington state at one time supported more than half of the Columbia River basin's summer steelhead and more than 40 percent of the spring and summer chinook salmon. But in the 1990s the runs were listed as threatened under the Endangered Species Act.