King salmon in Issaquah Creek in Issaquah, Wash.
About 1,100 king salmon died returning to a hatchery in Southeast, and officials suspect the cause was warm weather.
KFSK reports the fish died sometime last week at the Blind River rapids on southern Mitkof Island, south of Petersburg. The fish were returning to the Crystal Lake Hatchery.
Alaska Department of Fish and Game sportfish biologist Doug Fleming said he found the dead fish after last week's warm weather, when temperatures were in the 80s.
He suspects a combination of factors led to the die-off, including hot water, low oxygen levels in the water and a large number of fish trapped at Blind Slough.
Fleming says they were expecting 1,800 adult kings to return this year. Officials will have a better estimate later this year of how many survived.
MORE: Deadly Fish
These fish have a switchblade embedded in their tail, which could slash a swimmer and lead to amputation or a life-threatening loss of blood. (Photo: Wikimedia commons)