Southern California trout hatcheries resume stocking after Lactococcus detection

Additional information and strategies were developed including two new vaccines. 

Southern California trout hatcheries resume stocking after Lactococcus detection
Fish and Wildlife technician at Mojave River Hatchery applying hydrogen peroxide to raceways. Over 224,000 square feet of raceway were treated between the three hatcheries.
June 18, 2021

Hot Creek Hatchery is resuming the stocking of trout for recreational angling opportunities. The hatchery was recently placed under a temporary quarantine because of the discovery of a single fish infected with Lactococcus garvieae, the bacterial strain that led to the closures of three other Southern California hatcheries last year. The fish carrying the bacteria was not diseased. 

Following the discovery, California Department of Fish and Wildlife (CDFW) pathologists tested over 780 fish in the hatchery raceways and did not find any other fish carrying the bacteria. This pathogen can result in significant losses of fish within a hatchery. 

Since last year, CDFW has gained much additional information about this new pathogen and developed strategies partnering with the UC Davis Aquatic Animal Health lab to contain its spread. The work included using two new vaccines to protect fish from contracting this pathogen. Since the pathogen was discovered in just a single fish at Hot Creek Hatchery, CDFW was able to effectively monitor and contain its prevalence at the hatchery. Hot Creek Hatchery annually stocks around 600,000 trout per year across eight different waters in Inyo and Mono counties.