California is set to "humanely euthanize" 350,000 rainbow trout due to disease rapidly spreading through the state's population.
Californian rainbow trout populations at two government hatcheries are currently seeing a spike in bacterial infections that threaten the species' long-term health. Approximately 350,000 trout are thought to be affected.
Lactococcus petauri is a natural bacterium that can cause bulging eyes, erratic movement and high mortality in fish populations. The bacteria very rarely jumps from fish to humans.
The state Department of Fish and Wildlife announced it would be using "two different types of fish vaccines (immersion and injection) developed by scientists at the University of California, Davis, at the affected hatcheries."
The state's fish and wildlife officials issued statements assuring fishing enthusiasts that authorities were doing everything possible to keep the population high enough for angling.
"This loss is a huge disappointment, but we were prepared for this possibility and are doing all we can to ensure to continued angling opportunity for the public," said California Department of Fish and Wildlife Fisheries Supervisor Russell Black.
Black stressed that replacement populations from hatcheries, government stock and private suppliers would be used to supplement the rainbow trout supply.
He added, "The fish from the private contractor and stocks from non-infected hatchery facilities will help bridge the gap while we work to vaccinate the remaining stocks at the affected facilities. We are doing all we can to stock as many fish as possible."
The bacterial outbreak was first reported in April 2022.