SUCHES, GA (AP) - The U.S. Fish and Wildlife Service says an estimated 51,000 rainbow trout being raised at a hatchery in Georgia were killed when the main water supply had been cut off.

News outlets report the fish being raised at the Chattahoochee Forest National Fish Hatchery were killed Monday.

Fannin County Sheriff Dane Kirby says employees noticed the valve had been turned off and that the fish died.

Dan Chapman with the U.S. Fish and Wildlife Service says the dead fish were only a fraction of those at the hatchery. Chapman says a tree branch got stuck in the water supply gate, allowing some water to continue flowing through.

An investigation is ongoing, but authorities say there are no leads. The hatchery produces 1 million trout annually.

This story has been corrected to show the name of the agency is the U.S. Fish and Wildlife Service.

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