CDFW News

Invasive Bat Fungus Confirmed in Five California Counties

Mon, 28 Oct 2024 11:58:00 GMT

The fungus that causes white-nose syndrome in bats has been detected in several counties across California this year, although bats with visible signs of the disease have yet to be observed in the state.

White-nose syndrome has killed millions of bats across North America and decimated entire colonies. Hibernating bats like little brown myotis, Yuma myotis, and cave myotis are especially vulnerable. While white-nose syndrome is often fatal to hibernating bats, it does not infect humans, pets, livestock or other wildlife.

White-nose syndrome develops when the fungus Pseudogymnoascus destructans invades the skin cells of bats, resulting in damage to delicate wing membranes. The infection typically appears as white fuzz on the faces of infected bats, giving the syndrome its name. Bats with white-nose syndrome often end winter hibernation early, when water and insect prey resources are scarce, causing them to deplete their fat reserves and become dehydrated. As a result, infected bats often perish.

In 2023, the California Department of Fish and Wildlife (CDFW) first confirmed definitive presence of the fungus in a bat roost in Humboldt County. In 2024, the fungus was also confirmed present in Sutter, Placer, Amador, and Inyo counties. Inconclusive laboratory results suggest the fungus may also be present in Trinity, Siskiyou, Shasta, Plumas, Alpine, San Diego, and San Bernardino counties. Additional results are still pending for several other counties around the state. The fungus has been detected on several bat species in California, including the little brown myotis, Yuma myotis, long-legged myotis, big brown bat, Mexican free-tailed bat, and Western red bat.

This is the first time a Western red bat has been reported with presence of the fungus. The positive sample was returned from a female bat captured on May 9, 2024, in Sutter County. Both Western and Eastern red bats occur in California and can be difficult to differentiate, so CDFW used genetic sequencing to confirm this individual as Western red bat (Lasiurus frantzii, previously recognized as L. blossevillii).

While white-nose syndrome has not yet been observed in any bat in California, the presence of the fungal pathogen suggests the disease could manifest in California’s bats within the next few years. Such progression has been observed in other states, as the fungus and disease have been spreading across North America since discovery in 2006. The fungus was first detected on the West Coast in 2016 when it was discovered on a bat in King County, Wash.

While the fungus is primarily spread from contact between bats, humans can unintentionally spread it as well. People can carry fungal spores on clothing, shoes or recreation equipment that has come into contact with the fungus at bat roosts. To learn more about limiting the spread of white-nose syndrome, see the National White-nose Syndrome Decontamination Protocol (updated March 2024).

Biologists with CDFW, the National Park Service and U.S. Fish and Wildlife Service have been sampling California’s bats for the presence of the fungus and clinical signs of white-nose syndrome since 2016 in support of national surveillance efforts led by the U.S. Geological Survey National Wildlife Health Center. When bats at monitoring sites emerge from hibernation each spring, biologists swab their faces and wings to test for the fungus. Swabs are analyzed by the USGS National Wildlife Health Center and the Pathogen and Microbiome Institute at Northern Arizona University.

Sustained efforts to monitor bat populations will be critical to understanding and managing this devastating disease. CDFW and its partners will continue conducting white-nose syndrome surveillance and bat population monitoring across the state to assess potential impacts of the disease and inform research and management actions. The U.S. Fish and Wildlife Service leads the collaborative national response effort for white-nose syndrome through which scientists are continuing to develop and test innovative tools to manage the disease

California is home to 25 species of bats. A single bat can eat thousands of insects each night. California’s bats keep insect populations in check, benefiting rural, suburban and urban communities as well as a wide variety of natural landscapes that range from forests to deserts to grasslands. The pest control services that bats provide also protect crops and benefit California’s agricultural economy – the largest in the nation. Across the country, bats contribute approximately $3.7 billion worth of insect pest control for farmers each year and their guano can be used as fertilizer to improve soil health. Robust bat populations are vital to a healthy environment and economy.

CDFW urges people to not handle wildlife, especially dead wildlife or individuals that appear sick. If you find sick or dead bats, or notice bats acting strangely, please report your sighting. Bats flying or roosting outside during the winter is an example of noteworthy behavior that can sometimes, but not always, be associated with white-nose syndrome.

You can help watch for white-nose syndrome in California by reporting bat sightings to CDFW:

Report a Sick or Dead Bat
Report a Bat Colony

For more information about white-nose syndrome, visit www.whitenosesyndrome.org.

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Media Contacts:
Katrina Smith, CDFW Wildlife Branch, (916) 207-5573
Peter Tira, CDFW Communications, (916) 215-3858
Sydney Giuliano, U.S. Fish and Wildlife Public Affairs, (413) 658-4613

CDFW to Supplement Fish Stocks for Anglers as Bacterial Outbreak Leads to Further Losses at Two Eastern Sierra Trout Hatcheries

Mon, 20 Jun 2022 10:45:31 GMT

Two California Department of Fish and Wildlife (CDFW) trout hatcheries in the Eastern Sierra are continuing to fight an outbreak of Lactococcus petauri, a naturally occurring bacteria that sickens fish. The current outbreak was first detected in April 2022. CDFW fishery managers announced this week that approximately 350,000 infected catchable rainbow trout are now showing signs of disease and must be humanely euthanized.

The affected facilities – Black Rock and Fish Springs hatcheries – usually provide fish for stocking waterways in CDFW’s Inland Deserts Region. Because this is a significant loss of fish that would normally be stocked for anglers in the 2022 season, CDFW is working to contract with an external vendor to provide catchable rainbow trout for planting in Mono County. Approval of this contract is anticipated in July and stocking could begin soon after. In addition, other CDFW hatcheries across the state are supporting the eastern Sierra by providing and stocking fish in priority waters.

“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 CDFW Fisheries Supervisor Russell Black. “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.”

In addition to purchasing fish and redirecting existing stocks, CDFW’s plans to combat the outbreak and improve hatchery capabilities include:

The use of two different types of fish vaccines (immersion and injection) developed by scientists at the University of California, Davis, at the affected hatcheries.
Infrastructure improvements, including the installation of a new recirculation pump at Fish Springs Hatchery, and backup generators at Black Rock Hatchery and Hot Creek Hatchery.
Plans to modernize equipment, vehicles and facilities at other hatcheries throughout the state, both to improve drought resiliency and ensure that hatcheries are prepared to support each other when unexpected losses occur.
Pending proposals for five new hatchery technicians for the Inland Deserts Region, as well as an additional $5 million for fish food, water and electricity for the statewide hatchery system.

Lactococcus petauri occurs naturally in the environment and is usually spread by movement of fish or eggs. CDFW’s fish pathologists believe that it may have been carried into the hatcheries by birds that picked it up from an environmental source. Fish that are infected with the bacterium can show symptoms including bulging eyes, lethargic or erratic swimming and increased mortality, or be asymptomatic and show no signs of infection depending on several factors including water temperature and stress.

Fish-to-human transmission of this bacteria is rare and unlikely. As always, anglers should follow USDA recommendations on cooking fish to an internal temperature of 145 degrees F.

For additional information, please see CDFW’s frequently asked questions about the Lactococcus spp. outbreaks (PDF).

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Media Contacts:
Russell Black, CDFW Inland Deserts Region, (951) 852-6386
Ken Kundargi, CDFW Fisheries Branch, (916) 508-7788
Kirsten Macintyre, CDFW Communications, (916) 849-1714

New Bacterial Outbreak Confirmed at Two Eastern Sierra Fish Hatcheries

Thu, 21 Apr 2022 12:00:52 GMT

Two California Department of Fish and Wildlife (CDFW) fish hatchery facilities in the eastern Sierra have recently detected an outbreak of Lactococcus petauri, a naturally occurring bacteria that sickens fish. CDFW fishery managers are working to implement strategies that will help the facilities get the disease under control, without cancelling all trout plants prior to the traditional season opener on April 30.

The affected facilities – Black Rock Hatchery and Fish Springs Hatchery – usually provide fish for stocking waterways in CDFW’s Inland Deserts Region. Both facilities experienced a similar outbreak of Lactococcus garvieae in 2020, which led to the euthanization of approximately 3.2 million fish in order to stop the spread of disease (L. petauri is molecularly very similar to L. garvieae; the general abbreviation for both strains is Lactococcus spp.).

Earlier this month, the four raceways that hold catchable fish at Black Rock Hatchery tested positive for the Lactococcus bacteria. This accounts for approximately 120,000 trout, which would normally be stocked throughout the fishing season. At Fish Springs Hatchery, all lots of catchable fish (approximately 550,000 trout) tested positive. The current outbreak is among fish that have already received one round of vaccination.

In lieu of depopulating the affected hatcheries, non-diseased fish will be stocked into high-use waters that are hydrologically connected to the affected hatcheries and have cold water. This will mean increased plants for some locations and decreased plants for others. Diseased fish will be euthanized and not planted.

“This is unfortunate timing, as it affects our planting efforts in the weeks before the opener, but all is not lost,” said CDFW Director Charlton H. Bonham. “Fortunately, we learned much from the 2020 outbreak, and we have more knowledge and better tools to fight the bacterium this time around. We also believe we can continue stocking, with some adjustments and careful monitoring.”

Prior to the 2020 outbreak of Lactococcus, which is similar to streptococcus, the bacterium had never before been detected in fish in California, and thus there were no known effective treatments to employ. CDFW put three facilities under quarantine for more than a month, while pathologists and hatchery staff treated the affected fish. CDFW was successful in developing vaccines and continue to work on vaccine-related issues to improve efficiency.

Lactococcus spp. occurs naturally in the environment and is usually spread by movement of fish or eggs. CDFW’s fish pathologists believe that it may have been carried into the hatcheries by birds that picked it up from an environmental source. The current strain of bacteria is identical to one found in fish farms in central Mexico, which lends support to the hypothesis that birds using the pacific flyway are the likely vector for the spread of the bacteria. Fish that are infected with the bacterium can show symptoms including bulging eyes, lethargic or erratic swimming and increased mortality, or be asymptomatic and show no signs of infection depending on several factors including water temperature and stress. Fish-to-human transmission of this bacteria is rare and unlikely. As always, anglers should follow USDA recommendations on cooking fish to an internal temperature of 145 degrees F.

CDFW has initiated a phased priority stocking plan for the eastern Sierra. This plan will focus on planting high-use waters in southern Mono and northern Inyo counties. Similar to measures taken to handle the 2020 outbreak, CDFW will be investigating all available options to secure additional fish for increased planting opportunities, including redirecting fish plants from non-infected hatcheries. Results of the latest testing at Hot Creek Hatchery indicate that the fish in that facility’s upper raceways are cleared for planting at this time.

For additional information, please see CDFW’s frequently asked questions about the Lactococcus spp. outbreaks (PDF).

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Media Contacts:
Russell Black, CDFW Inland Deserts Region, (951) 852-6386
Ken Kundargi, CDFW Fisheries Branch, (916) 508-7788
Kirsten Macintyre, CDFW Communications, (916) 849-1714