SPOKANE, Wash. (AP) — Washington officials have declared an early end to the sockeye salmon season on the upper Columbia River.

The Spokesman-Review reports anglers will not be allowed to keep any sockeye they catch from Rocky Reach Dam upstream to Chief Joseph Dam as of Sunday a half hour after sunset. The emergency closure is being called because of elevated water temperatures in the Columbia River.

The rule does not affect fishing for summer chinook. Officials with the Washington Fish and Wildlife Department say half this year's fish heading to the spawning grounds died on their way. Jeff Korth, the regional fisheries manager in Ephrata, says he's never seen anything like this year in his 29-year career.

He estimates at least 300,000 adult salmon have died or will die on the upper Columbia River before reaching their spawning grounds.