Recent accomplishments of CDFW's scientific community
Working late, Mojave River hatchery staff apply FDA-certified epoxy coating to hatchery rearing ponds.
CDFW fish transportation truck at Fillmore Hatchery
Acting Mojave River Hatchery Manager Forest Williams at work
A hatchery crew releases trout into the Feather River
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
For some public properties, livestock grazing can be an important land management tool to help maintain specific habitat conditions, control invasive weeds and reduce fire hazards. In areas invaded by non-native vegetative species, it is necessary to control vegetation height and density in order to keep habitats functioning for certain sensitive species. For instance, the burrowing owl requires low vegetation cover in order to forage for prey effectively and prevent predators from approaching unseen. Other species that have been known to benefit from managed livestock grazing include California tiger salamander, Yosemite toad and certain sensitive butterfly species.
Controlling the height and density of non-native annual grasslands through grazing has also been shown to help increase forage efficiency for many species of raptors, and it’s used as a tool in some areas of California to maintain sensitive vernal pool habitats.
For years, local, state and federal agencies, as well as non-government organizations, have utilized livestock grazing on public lands. It is important to have many tools available for habitat management because it can sometimes be complicated. Factors such as the presence of listed or protected species, compatible public land uses and erosion -- as well as other land management practices such as herbicide application, mowing and prescribed fires -- must all be considered.
CDFW’s Rancho Jamul Ecological Reserve in San Diego County recently hosted a livestock grazing workshop presented by Rancher to Rancher (R2R) program spokesperson Kent Reeves, and UC Davis researcher Dr. Christina Wolf. The goal of the R2R program is to provide information and educational resources to private ranchers about evolving livestock management practices intended to promote native ecosystem health, and therefore, more sustainable grazing programs. More than 40 participants, including local private ranchers and representatives from about a dozen government and non-government organizations attended the workshop. Participants learned about developing progressive management practices, such as the use of increased stocking densities for shorter, more frequent durations, in order to increase carbon sequestration in the soils. This method is currently being studied as a way of encouraging native grass species as well as combating changing climate conditions.
California’s coastal waters are home to seven species of abalone, and all but one are endangered or listed as species of special concern. The white abalone in particular has been nearly decimated by overfishing and disease, and scientists can find no evidence that the remaining population is reproducing in the wild. In order to avoid loss of the entire species, CDFW and partner agencies have formed the White Abalone Recovery Consortium, which will employ captive rearing and restoration stocking efforts and extensive public outreach in order to save these animals from extinction. It will be an ongoing, long-term project, but all signs point to future success – already there are more white abalone thriving in the captive breeding program than the entire population living in the wild.
Read more about the efforts to restore California’s white abalone – and learn what you can do to help! – on the CDFW Marine Management News Blog.
A California red-legged frog sits motionless at the edge of McClure pond at the Sparling Ranch Conservation Bank. Photo by Ashley Spratt/USFWS
McClure pond is one of the most productive California red-legged frog ponds at the Sparling Ranch Conservation Bank. Like many of those on Sparling Ranch, it was named after the family who homesteaded in site in the late 1800s. Photo by Ashley Spratt/USFWS
Since the mid-1980s, California has been using a system of conservation and mitigation banking to protect valuable natural resources and critical habitat for fish, wildlife and plants. These banks are generally large, connected, ecologically meaningful areas of preserved, restored, enhanced or constructed habitat (for example, wetlands) that are set aside for the express purpose of providing mitigation for project impacts. Conservation banks provide mitigation for impacts to listed species and habitats, while wetland mitigation banks primarily provide mitigation for wetland impacts. Together, they serve to prevent inadequate, fragmented reserves that can result when mitigation projects are carried out individually.
Banks work by establishing credits for sensitive species or habitats found on a given site. These credits can then be sold to developers or other project proponents who need to meet permitting requirements or are otherwise required to compensate for environmental impacts. For those parties needing to mitigate for project impacts, banks serve to streamline the regulatory process by providing a pre-established mitigation site that the regulating state and federal agencies have already confirmed will provide adequate and appropriate mitigation for certain habitats or species. By mitigating at a bank, project proponents can avoid the time and cost of searching for a suitable mitigation site and protecting it in perpetuity themselves.
In order for the banking system to be effective, state and federal agencies must work closely together to align processes and practices. Since 1993, CDFW has been participating in the planning, review, approval, establishment, monitoring and oversight of 81 banks statewide. Other agencies that typically participate in the regulation and approval of conservation banks include the U.S. Army Corps of Engineers (USACE), U.S. Environmental Protection Agency (USEPA), Natural Resources Conservation Service (NRCS), U.S. Fish and Wildlife Service (USFWS) and the National Oceanic and Atmospheric Administration National Marine Fisheries Service (NOAA NMFS).
To read more about one of these successful partnerships, please visit USFWS’ newsroom.
Learn more about CDFW’s Conservation and Mitigation Banking program, on our website.
All photos courtesy of U.S. Fish and Wildlife Service.
Top photo: A herd of cattle graze atop a hillside at Sparling Ranch near Hollister, Calif. Photo by Ashley Spratt/USFWS.
For more than a century, CDFW’s Trout Hatchery and Stocking Program has been providing recreational fishing opportunities to anglers throughout California. Today, the trout hatchery program is composed of 13 hatcheries, which oversee 20 distinct fish production programs to produce 17 strains, species and subspecies of trout.
McCloud River Redband Trout (Oncorhynchus mykiss stonei) is the latest addition to the CDFW’s production and release efforts. McCloud River Redband Trout is a unique sub-species of rainbow trout endemic to the upper McCloud River area of Shasta and Siskiyou counties of northern California. This fish has beautiful coloration and unique adult characteristics – a pronounced crimson lateral stripe, adult parr marks, relatively large black dorsal spotting, yellow-white hues on the underbelly and white-tipped fins.
The new production and stocking program for McCloud River Redband Trout at Mt. Shasta Fish Hatchery will focus on the upper McCloud River, including McCloud Reservoir. Given that stocking will occur solely within the historic watershed of McCloud River Redband Trout, the program is distinguished by CDFW as a Heritage Trout Production Program. A Heritage Trout is defined as a species of trout native to California, in its native habitat and area. This type of fishery represents the most natural form of aquatic habitat, species and angling opportunity available. Many anglers seeking additional challenges and goals will specifically pursue heritage trout fisheries.
While modern genetics management and conservation hatchery methods are utilized in the McCloud River Redband program, the hatchery-produced fish are primarily for recreational angling and not for release to areas containing wild and genetically pure McCloud River Redband Trout in their natural habitat. This ensures that the most wild populations remain in their native habitat and can continue local adaptation without hatchery influence. CDFW expects the McCloud River Redband Trout program to reach full implementation by 2019-20. The McCloud River Redband program demonstrates CDFW’s progress and commitment to conservation efforts and fisheries management.
CDFW trout hatcheries will continue to produce and stock several strains and species of trout statewide to promote trout angling opportunities, and contribute to the conservation of California’s native species and sub-species of trout. One of the next priorities for the department’s trout hatchery program will commence in 2018, and focus on advancing the Kern River Rainbow Trout program at CDFWs’ Kern River Planting Base.
CDFW Fish and Wildlife Technician Beau Jones stocking McCloud River Redband Trout in August 2017. CDFW photos by hatchery staff.
This summer marked the end of an incredible journey for four dozen of California’s designated state freshwater fish, the golden trout, as they returned home after 10 months away. The fish traveled more than 500 miles in tanks and buckets, by hand and by mule, en route to their native waters 9,000 feet up in the Sierra Nevada range.
The journey began last fall after CDFW scientists observed that ongoing drought conditions were severely impacting the rare trout’s mountainous habitat. A decision was made to rescue 52 fish – a representative population that could repopulate the stream and save the species if drought conditions worsened.
Golden trout are one of California’s most iconic trout species. They are native to only two stream systems in the southeast Sierra Nevada – Golden Trout Creek, and the South Fork Kern River in Tulare County. Volcanic Creek, which is home to the rescued fish, connects with Golden Trout Creek during runoff and high-water level years.
The journey began in September 2016, when fisheries biologists made the two-day trek into the mountains to gather the trout. The captured fish were transported to the American River Trout Hatchery near Sacramento, where technicians monitored them, often around the clock. After nine months at the hatchery, the fish were ready to start the long trek back to their home waters. Crew members transferred the fish from the hatchery to a fish tanker truck and hauled them more than seven hours overnight to the trailhead at an elevation of 10,000 feet in the southern Sierra.
The crew met up with a CDFW team that would escort the fish on horseback, 16 miles into the Inyo National Forest. Federal laws forbids motorized vehicles on wilderness land, which left the team no option but to transport the fish by mule train in fish cans.
The operation took tremendous teamwork from multiple divisions in CDFW and the National Forest Service. Ultimately, the CDFW team successfully returned 48 fish to their natural element. Four died in captivity over the winter. CDFW officials consider that a normal mortality rate. Scientists remain optimistic that these iconic fish will continue to thrive and perhaps even be on-track for a brighter future.
See related VIDEO.
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 imperiled in California due to the two-pronged impact of introduced (non-native) trout and chytridiomycosis, a disease that is affecting amphibians worldwide.
Past introduction of non-native fish, including rainbow trout and golden trout, to benefit sport fishing in the High Sierra took a heavy toll on the species. High-elevation lakes where these frogs once flourished were largely fishless until fish stocking came into vogue. As the years passed, scientists determined that these introduced fish were depopulating the frogs by competing for food sources (primarily insects) and by predation (trout ate both adult frogs and their tadpoles). Chytridiomycosis, which affects many frog species, also impaired the ability of the Sierra Nevada yellow-legged frog’s skin to exchange vital nutrients, which often leads to death.
As a result, Sierra Nevada yellow-legged frogs are believed to have vanished from approximately 92 percent of their historical habitat, and halting and reversing that decline has become an important goal of CDFW, as well as other state and federal entities.
“This is an animal that only lives in the Sierra Nevada,” said Sarah Mussulman, a CDFW senior environmental scientist. “It is one of our unique California species that lives in high-elevation areas, and as an amphibian it serves as an important link between the terrestrial and aquatic ecosystems. This link is especially critical in the low nutrient, granitic basins of the High Sierra, where frogs and tadpoles consume insects and algae and are themselves consumed by a variety of snakes, birds and mammals.”
CDFW recently completed two projects as part of its ongoing efforts to reverse the population decline of Sierra Nevada yellow-legged frogs.
The efforts took place at two sites: Highland Lake and Clyde Lake, located approximately seven miles apart on the Rubicon River in the Desolation Wilderness area of El Dorado County. The projects were completed with federal grant funds earmarked for the recovery of endangered and threatened species (the species is listed as threatened by the State of California and as endangered by the U.S. Fish and Wildlife Service).
Highland Lake, along with its outlet, an unnamed stream, and two small adjacent ponds, supported a small population of rainbow trout when the project began in 2012. Trout abundance had declined in the absence of stocking in recent years but sufficient natural reproduction occurred in the inlet to Highland Lake to sustain the population. CDFW began using gill nets to remove rainbow trout -- the descendants of fish planted in the lake by CDFW from 1935 to 2000 -- in 2012, in partnership with Eldorado National Forest personnel.
During a frog-monitoring survey at Highland Lake in 2016, approximately 800 adult frogs were observed, as compared to a 2003 survey in which only a few tadpoles were observed. Because the frogs have consistently survived in this area despite the presence of chytridiomycosis, scientists believe they have a good chance at persisting in the area for a long time.
“Highland really had a population explosion over the past five years and can be counted as one of the most successful projects of this type ever undertaken,” Mussulman said.
The project at Clyde Lake was smaller and had somewhat different factors.
Golden trout, which frequently have the same negative impacts on Sierra Nevada yellow-legged frogs as rainbow trout, including predation and competition for food sources, were planted by CDFW at Clyde Lake from 1932 through 2000.
Once stocking was halted, the golden trout proved less resilient then the rainbow trout at Highland Lake, due to habitat factors.
“Clyde Lake sits in a north-facing granite bowl bordered by 1,000-foot cliffs, and no flowing streams enter the lake,” explained Mussulman. “There was no spawning habitat, which is likely why golden trout did not persist there after stocking was halted.”
The stream flowing out of Clyde Lake and four nearby ponds did support a small population of golden trout after plants were halted. The fish in the stream and ponds, which are self-sustaining populations, are precluded from moving from the stream into Clyde Lake by a fabricated dam. In 2013, frogs and a few tadpoles were observed in the stream alongside fish, and CDFW began removing the fish from the stream with gill nets to provide additional habitat for the frogs.
Nine years of monitoring data collected by CDFW scientists indicate that the area’s Sierra Nevada yellow-legged frog population, while small, is slowly increasing. Surveyors observed more than 120 frogs in 2016, compared to a low of six observed in 2005. Moreover, in 2016, for the first time, dozens of tadpoles were observed in the newly fish-free lower reaches of the stream.
“It is great to see these populations recovering,” Mussulman said. “It is a great privilege doing this work that helps keep these frogs on the landscape.”
CDFW photos: Highland Lake in the Desolation Wilderness, and a Sierra Nevada yellow-legged frog
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