Second Outbreak Bacterial Outbreak Found in Hot Creek Trout Hatchery

MONO COUNTY一 The California Department of Fish and Wildlife has temporarily suspended fish planting from the Hot Creek Trout Hatchery in Mono County after a bacterial outbreak of Lactococcus garvieae was discovered in the hatchery’s trout population.

Hot Creek Trout Hatchery raises three species of trout, rainbow, brown, and Lahontan cutthroat. The hatchery is south of Mammoth Lakes and stocks some eastern Sierra fisheries including, Crowley Lake, Pleasant Valley Reservoir, and portions of Owens Rivers.

Fifteen percent of the hatchery’s total trout population tested positive for the bacteria, 118,000 rainbow trout and 52,000 brown trout including, 2,000 brood stock brown trout weighing two to three pounds each.

The bacterial outbreak was first detected in California in 2020 and caused quarantine and suspension of fish planting in three hatcheries throughout California. The previous outbreak forced the euthanizing of 3.2 million trout.

Fish that have been infected with Lactococcus garvieae can express symptoms like bulging eyes, lethargic or erratic swimming, and increased mortality. Some fish present asymptomatic due to factors like water temperature and stress.

Fish-to-human transmission is rare and unlikely, but cases have been documented where immunocompromised people consumed infected raw fish.

The CDFW has quarantined the facility and suspended fish planting while it prepares to euthanize the infected fish and vaccinate the uninfected stock through injections or a bath immersion process.