Sludge Spill Kills 150,000 Eagle Trout in California


The California Department of Fish and Wildlife (CDFW) announced on Wednesday that more than 150,000 Eagle Lake trout died in American River Hatchery after routine maintenance on a pipe caused a flow of dirty water and gunk to flood the hatchery, causing a chiller to fail. Officials attributed the fish kill to rising temperatures afterwards.

“We already had less inventory than we wanted for this hatchery,” CDFW hatchery systems manager Bill Cox told The Sacramento Bee. “Now, if we lose those fish, that’s a big hit. Now, we’re going to have to figure out what we’re going to do about it.”

Officials speculated that the incident may have been caused by a nearby dredging operation. The US Bureau of Reclamation, which also owns the hatchery, was conducting maintenance on a pipe connected to the Nimbus Dam when some sort of failure occurred and allowed sludge from the pipe to flow into the hatchery. The thick substance clogged the hatchery’s cooling and filtration system, which caused the fish to overheat and suffocate in their holding ponds.

The incident killed off more than 78 percent of the hatchery’s Eagle Lake trout and did minor damage to the population of Shasta and Lahontan cutthroat trout. Officials said that due to the fish kill, the hatchery will likely be unable to stock streams and lakes in the Sacramento region at an ideal level.

“Additional losses are expected because of stress to the fish and continuing elevated water temperatures,” stated a press release from the CDFW.

That is because the surviving fish in the hatchery are now languishing in higher-than-average water temperatures. The ideal water temperature for Eagle Lake trout is near 55 degrees Fahrenheit, but the current water temperature is closer to 70 degrees. Officials are currently working on repairing at least one of the chillers on site. An investigation is also underway to determine the cause of the pipe failure.

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