Accidents at two Sitka hatcheries over the weekend have killed more than one million juvenile salmon in the US state of Alaska.

Northern Southeast Regional Aquaculture Association (NSRAA) lost 950,000 chinook juveniles at its Medvejie hatchery on July 2 when a water valve was mistakenly turned off, according to reports.

The crew was cleaning a salmon pit and shifting from one fresh water source to another when a valve was inadvertently closed, said Steve Reifenstuhl, NSRAA's general manager. The salmon hatched last year and would have been released next spring.

NRSAA produces about 4 million chinook eggs a year.

At the Sheldon Jackson College hatchery, staff on July 5 discovered that an alarm system failed to indicate that the water level in the rearing tanks had fallen, resulting in the deaths of 115,000 chinook and 115,000 coho.

Staff managed to save about 5,000 fish.

The hatchery released 10 million chum and one million pink salmon in the spring.