Menu
Contact Us Search

Science Spotlight

Science Institute News

rss

Recent accomplishments of CDFW's scientific community


Bringing the Paiute Cutthroat Trout Home

Bringing the Paiute Cutthroat Trout Home

a woman wearing a California Fish and Wildlife uniform, standing in waist-high grasses, connects cables in a 1-foot-square, plastic box.
CDFW Scientific Aide Aimee Taylor prepares electrofisher to harmlessly catch Paiute cutthroat trout in North Fork Cottonwood Creek.

an irridescent gray, purple, pink and white cutthroat trout hovers in the sunlit water of a shallow creek
The extremely rare Paiute cutthroat trout (PCT). Photo by William Somer for CDFW.

Two people wearing Fish and Wildlife uniforms stand in a shallow mountain stream, surrounded by lush Alpine vegetation
Aimee Taylor and Senior Environmental Scientist Jeff Weaver electrofish PCT in North Fork Cottonwood Creek.

Four people kneel in green grass next to a stream, huddled around something on the ground
Jeff Weaver, USFWS Biologist Chad Mellison and others take genetic samples from the fish.

At a pack station with horses in the background, two men transfer fish by net, into an old-fashioned milk can.
The project’s lead biologist, Bill Somer, and Chad Mellison transfer the trout from CDFW’s tank truck to cans for the ride to Silver King Creek, by pack mule.

A pack train of seven loaded mules and three riders on horseback traverse a high mountain plain under a partly cloudy sky
The CDFW-FWS-USFS team packs pure PCT in milk cans through the Silver King drainage.

A man wearing hip waders and a California Fish and Wildlife uniform stands knee-deep in a stream that runs through a green meadow, where he lowers a white bucket into the water to release two small fish.
Bill Somer releases Paiute cutthroat trout into Silver King Creek, above Llewellyn Falls.

A trout lies in an elongated net with measuring marks, held next to a white bucket with water and other live fish in it.
Team members measured each Paiute cutthroat trout caught at White Mountain.

The California Department of Fish and Wildlife (CDFW), U.S. Fish and Wildlife Service (FWS), and U.S. Forest Service (USFS) have returned a rare trout species to its home water after a 71-year absence.

In 1946, poachers were decimating the Paiute Cutthroat Trout (PCT), a species whose native range was limited to a nine-mile section of Silver King Creek (Alpine County). To ensure the species’ survival, the USFS and Eastern Packers Association translocated 401 of these fish to North Fork Cottonwood Creek in Inyo County’s White Mountains. This population has persisted in isolation from other forms of trout and has recently provided important restoration options for resource managers. None of this would have been possible without the foresight of concerned biologists seven decades ago.

The conservation history of this rare trout is complex. The initial “conservation” measure was entirely inadvertent. In the early 1900s, Basque sheepherders in the area caught and transported PCT into the previously fishless portion of Silver King Creek above Llewellyn Falls. This early within-basin transfer was the salvation of the PCT, since non-native species were later introduced below the falls. The falls prevented non-natives from reaching the habitat above and protected PCT from hybridization and competition.

The FWS listed PCT as endangered under the Endangered Species Preservation Act of 1966 – the precursor to the federal Endangered Species Act (1973). The species was down-listed to threatened status in 1975, in order to facilitate management and restoration and to allow regulated angling. In 1994, CDFW, FWS and USFS began developing a restoration plan to remove non-native fishes from Silver King Creek and return the PCT to its native waters. From 2013 to 2015, the partner agencies treated 11 stream miles of Silver King Creek and three tributaries below Llewellyn Falls with a fish toxicant, rotenone, to remove all non-native fish species.

The PCT population in Upper Fish Valley, an area of Silver King Creek above the falls, has been considered a primary source for restocking the recovery area. Unfortunately, that population was heavily impacted by the extreme 2012-2016 drought. During this extended drought, lack of snow cover resulted in the stream freezing almost solid during cold snaps. In order to offset the resulting population decline, the partner agencies caught 86 pure PCT in North Fork Cottonwood Creek. On August 23, 2017, the fish were planted back into Silver King Creek above Llewellyn Falls.

Agency staff met in the White Mountain Wilderness (Inyo National Forest) and, along with volunteers and pack mules, hiked from their campsite to North Fork Cottonwood Creek. There, the team used electrofishers to retrieve descendants of the fish moved back in 1946. The fish were hauled out by mule, put in a specialized transport truck, and driven approximately 100 miles to the Carson Iceberg Wilderness. Another mule team then hauled them back to Silver King Creek. Thanks to careful handling by the collection and transport teams, every fish survived the trip home.

Due to its limited habitat, the Paiute Cutthroat Trout has been called the rarest, but most recoverable, form of trout in the United States. With the most recent success of this partnership, and due in large part to the foresight of conservationists in the past, the future looks bright for this beautiful native salmonid.

Learn more on the Paiute cutthroat trout web page.

Photos by Joe Barker, courtesy of U.S. Fish and Wildlife Service, except as noted.

Top photo:
Liz Vandentoorn, from the Inyo National Forest Region 5 Center of Excellence, leads a pack mule team and state and federal scientists to North Fork Cottonwood Creek to capture Paiute cutthroat trout and return them to Silver King Creek.


Stacking the Odds to Stock California’s Waters

Stacking the Odds to Stock California’s Waters

Three men brush a white epoxy on a 600-foot-long by 5-foot wide concrete channel
Working late, Mojave River hatchery staff apply FDA-certified epoxy coating to hatchery rearing ponds.

a tank truck parked next to a concrete fish hatchery raceway with palm trees in background
CDFW fish transportation truck at Fillmore Hatchery

An African American man in a California Fish and Wildlife uniform squats to read something on a low concrete wall at a fish hatchery
Acting Mojave River Hatchery Manager Forest Williams at work

Seven people watch fish come out of a 10-foot pipe from a CDFW tank truck, into a root beer-colored river
A hatchery crew releases trout into the Feather River

view from river-level of water and fish pouring from a tank truck, through a pipe
A fishy view of trout planting on the Feather River

The beginning of trout fishing season in Southern California is just around the corner, and CDFW biologists and hatchery staff are striving to maximize hatchery trout availability for the many anglers who will cast lines in coming weeks. Trout angling in lower-elevation waters of Southern California generally begins in November and continues through April, to correspond with colder water temperatures that can sustain stocked trout.

Precise temperatures are just one of the criteria that must be met before trout stocking begins. Currently, these conditions are approaching optimal levels, but CDFW is running about two weeks behind schedule due to unforeseen circumstances at Mojave River and Fillmore trout hatcheries, two of CDFW’s southernmost facilities.

The Mojave River Hatchery, built in 1947, raises and stocks a ten-year average of 340,000 pounds of catchable trout per year. Beginning in June of this year, extensive maintenance and facility upgrades necessitated turning off the water for a six-month period. While the completed upgrades will ultimately result in better and more efficient trout production for Southern California, the project ran about two months behind schedule. Water is scheduled to flow again at Mojave River Hatchery in late November and the hatchery will be populated with fingerling trout for fast growth. Mojave’s year-round water temperatures yield fast trout growth resulting in maximized yield in minimal time.

While the Mojave River Hatchery was closed, Fillmore Hatchery, built in 1941 on the Santa Clara River, experienced a significant loss of trout inventory intended for Southern California angling due to gas bubble disease. Gas bubble disease is a result of supersaturated gasses (oxygen, nitrogen and carbon dioxide) present in well water pumped from a deep aquifer. While Fillmore Hatchery is equipped to aerate this water and make it suitable for trout, an unknown variable (possibly a drought-depleted and then recharged aquifer) overwhelmed that ability. In an average year, Fillmore Hatchery produces about 400,000 trout for lakes and streams in Southern California. To reduce fish losses from gas bubble disease in the last several weeks, catchable fish were stocked from Fillmore to appropriate waters, and some fish were transferred to other hatcheries. Ultimately, the gas bubble disease at Fillmore resulted in a loss of about 50 percent of inventory. While emergency measures taken by Fillmore staff and

CDFW fish pathologists resulted in better conditions and lower gas super-saturation, the hatchery must be depopulated so that the issue can be addressed entirely. As soon as all trout are removed, hatchery staff and scientists will increase the gas diffusion capability of aeration towers at Fillmore, in order to handle supersaturated well water for the short and long term.

The status of these two hatcheries presented a substantial problem for trout stocking in Southern California that was solved in part by hatcheries in Central and Northern California. These hatcheries have sufficient catchable size trout to supply Southern California’s approved waters immediately and in coming weeks. Thanks to strategic planning and trout production at a statewide level, Northern and Central California can supply fish to Southern California without impacting originally scheduled trout releases in their respective areas.

Trout stocking for Southern California waters will begin this week and hatchery trucks are on the move. Hatchery staff will work quickly to distribute trout to as many approved waters as possible. Trout stocking to Southern California will initially be lighter than usual, but will likely pick back up in 2018. As Mojave River Hatchery comes back online, fish transferred to that facility will be fed and reared to maximize daily growth. We anticipate another large batch of catchable trout available for Southern California toward early spring 2018.

Hatchery staff will be doing everything possible, statewide, to maximize trout production and releases to approved waters in the coming months. Staff work diligently for the angling public and appreciate their continued support.

The statewide planting schedule is updated in real time online.

CDFW photos. Top: Steelhead trout at Mokelumne River Hatchery



Recent Posts

  • For 21 Years, Volunteer Has Kept Tabs on Morro Bay’s Black Brant Posted 6 days ago
    Banded black brant feeding on eelgrass Volunteer John Roser in the field at Morro Bay Flock of black brant in flight above Morro Bay Black brant in Morro Bay John Roser began hearing the stories shortly after he moved to Los Osos, San ...
  • CDFW Gets a Jump on Preserving Sierra Nevada Yellow-legged Frogs Posted 2 weeks ago
    It does not take a leap of faith to believe that CDFW scientists have gained the upper hand in bolstering the population of yellow-legged frogs in the High Sierra. Over the past three decades, Sierra Nevada yellow-legged frogs have become ...
  • California Fish and Game, Volume 103, Issue 3 Posted 3 weeks ago
    The latest issue of California Fish and Game, 103-3, makes a significant contribution to the body of research related to longfin smelt in California. A paper titled, “Historic and contemporary distribution of Longfin Smelt (Spirinchus thaleichthys) along the California ...
  • The Challenges of Studying Roosevelt Elk Posted 3 weeks ago
    For residents of Humboldt and Del Norte counties, the majestic Roosevelt elk is a common sight. Although Roosevelt numbers were dwindling in California by the 1920s, conservative management strategies and limited hunting opportunities have helped them to rebound. Today, ...
  • Badly Burned Ursines Get Back on their Feet – Thanks to Teamwork and Fish Skin Posted last month
    The tilapia skin is visible on the bottom of the bear's paw. Veterinarians perform an ultrasound to check on the progress of the second bear's pregnancy. Acupuncture needles assist with pain management. After placing the second bear, the team moved the first ...
Read More »

CDFW Science Institute logo