Can A New Fish Vaccine Save Hot Creek Hatchery?

Jon Klusmire
Special to the Times

This sounds eerily familiar: Experts are hoping new vaccines can come to the rescue by stopping a deadly disease and heading off a large-scale tragedy.
But the vaccines in question have nothing to do with the coronavirus.

Instead, fish pathologists are assessing whether new vaccines can be deployed to help save the lives of hundreds of thousands of trout that have been exposed to a bacterial infection at the Hot Creek Trout Hatchery in Mono County.

“We’re hoping we can use a vaccine to treat and save many of these fish,” said Peter Tira, public information officer for the California Department of Fish and Wildlife, regarding the department’s plans for dealing with the outbreak of Lactococcus garvieae.

The bacterial outbreak was detected the Hot Creek Trout Hatchery last week, prompting the department to suspend all fish plants from the hatchery. The same disease showed up in the summer of 2020 and caused DFW to kill about 3.2 million trout in its Warm Springs and Black Rock hatcheries in Inyo County and the Mojave River Hatchery.

Since that outbreak, “we have some new tools we didn’t have last year,” Tira said, “so we’re hoping for the best” which would be to avoid the largescale fish euthanasia used at the three other hatcheries. Those new tools include the new vaccine and other techniques to combat the potentially deadly outbreak. The DFW “rolled out” the recently developed vaccines in May at the three previously infected hatcheries, said Jay Rowan, Acting Fisheries Branch Chief for DFW.

On Wednesday, June 2, fisheries experts and hatchery opera- tors were still monitoring the Hot Creek hatchery, testing the fish, the hatchery facilities and the water for the bacteria, and assessing the extent and severity of the infection, Tira said. Once those initial assessments are complete and a detailed plan is in place, “we hope we can prepare the hatchery and fish for using the vaccine,” he said.

The Hot Creek Trout Hatchery produces and stocks about 500,000 catchable trout a year in Inyo and Mono counties. “It’s definitely one of our major hatcheries,” Tira said. Several large plants were scheduled in the coming weeks from Hot Creek, but they have been put on hold. “Anglers in the Eastern Sierra will definitely” see fewer trout being stocked by DFW in local waters.

Since the first three hatcheries were taken offline, the DFW fall in stocked trout in the Eastern Sierra, Tira said, and that effort will continue. The department estimates about 400,000 trout from other DFW hatcheries have been planted in the Eastern Sierra. “But there are only so many fish you can produce. It take a long time for trout to grow,” Tira said, so additional “re- allocations” of trout are unlikely.

Tira pointed out that local businesses and governments also buy and stock trout.

Mono County spends about $100,000 a year to bring in trout from a hatchery in Oregon, according to Alicia Vennos the county economic development direc- tor. Mammoth Lakes Tourism also buys and stocks trout in the area, she added. Vennos said the county will be monitoring the situation and assessing if it can step up its fish stocking efforts.
The Bishop Creek Canyon businesses also buy and bring in larger, trophy trout to stock in South Lake, Sabrina and Intake II. The group recently brought in about 700 pounds of trout for the three lakes and Bishop Creek.

The Hot Creek Trout Hatchery raises four species of trout – rainbow trout, brown trout, Eagle Lake trout and Lahontan cutthroat trout – which are stocked in Inyo and Mono counties. The potential loss of the Hot Creek Trout Hatchery would deal another major setback to the effort to lure anglers back to the Eastern Sierra after a year of pandemic lock-downs and then the loss of millions of hatch- ery trout which curtailed stocking in both counties for the second half of 2020.

It typically takes between 10 months and two years to grow “catchable” trout of about a half pound in a hatchery. Trout eggs generally start arriving at the hatcheries in December. Catchable fish from Mojave could be ready by the end of 2021. At Black Rock and Fish Springs, DFW estimated catchable trout will not ready for stocking until the spring of 2022.

The outbreak of Lactococcus garvieae, which is similar to streptococcus, has been reported in cattle and poultry farms as well as fresh and saltwater fish and shellfish hatcheries around the world, according to DFW. Fish-to-human transmission of the bacteria is rare and unlikely.