Science Spotlight

The 2020 Slink Fire burns part of the Slinkard/Little Antelope Wildlife Area, Mono County. Photo © Jeff Sullivan Photography


Fire damage in the Slinkard/Little Antelope Wildlife Area, Mono County. CDFW Photo


CDA and CDFW prepare a helicopter for aerial seeding. California Deer Association Deer photo


CDA using tractor for mechanical seeding. California Deer Association photo


A helicopter shortly after takeoff, on its way to aerial seeding. California Deer Association Photo

The eight largest fires in California history have consumed more than 4 million acres and burned more than 7,000 structures. And because all those fires happened just within the last five years, the state of California recently approved spending hundreds of millions of dollars through its Wildfire and Forest Resilience Action Plan (PDF).

For the California Department of Fish and Wildlife (CDFW), that means being able to significantly expand the scope of wildfire resiliency projects such as fuel reduction and forest health projects, as well as to restore habitat on CDFW lands that have burned recently. In northern Mono County, where the 2017 Slinkard Fire and 2020 Slink Fire together burned nearly 40 percent of the 11,700-acre Slinkard/Little Antelope Wildlife Area, CDFW is working hard with project partners to implement restoration and fuel reduction projects. That work includes seeding a mix of shrubs and grasses, planting nursery-grown bitterbrush, reforestation of Jeffrey pine and white fir, mowing fuel breaks and removal of invasive species.

“For the last century, fire suppression and climate change have led to larger fires that burn hotter and can leave the landscape more vulnerable to invasive nonnative plants, making natural recovery more challenging,” said Senior Environmental Scientist Aaron Johnson. He explained that the work being done at the wildlife area has two purposes: to improve habitat for mule deer, and expedite recovery of the desired natural communities, thus mitigating the potential transition to non-native annual grasses that contributes to the severity of fires.

“Cheatgrass does very well in the post-fire burned landscape, and once established, it increases the frequency and severity of wildfires on the landscape,” Johnson said. “Parts of Slinkard have burned enough times that there’s nothing but cheatgrass, and even the smallest lightning strike that might have historically burned a single tree can now lead to thousands of acres burned.”

California’s Wildfire and Forest Resilience Action Plan guides the work done by Johnson and Graham Meese, a new CDFW employee hired specifically for this purpose. Part of Meese’s job involves coordinating with groups and agencies outside CDFW that bring specific expertise such as fuel reduction or seeding.

“By building partnerships, we’re able to effectively increase the scale of work that we’re able to do,” Meese said. “I could spend all year seeding one meadow by myself, but with the state funding CDFW has received, we’re able to contract with nonprofits like the California Deer Association (CDA) to get landscape scale projects done.”

CDA has directed the aerial seeding on more than 2,000 acres within the Slinkard/Little Antelope Wildlife Area, while also conducting site surveys and the removal of hazardous burned trees. “The amount of work that CDA has completed in such a short period of time is impressive,” he said, adding that CDA staff and contractors will significantly increase CDFW’s capacity to tackle such projects over the next several years.

CDA describes itself as a wildlife conservation organization whose goal is improving the state’s deer herds and other wildlife. They have roughly 12,000 members – 10 of whom spent about a week last November repairing damage from the Slink Fire.

“We’re starting to see where repetitive fires burning within the same footprints are causing changes in vegetation and promoting invasives,” said CDA Communications Manager Cherise MacDougall. The CDA also sees changes in climate and the makeup of California as reasons to step in and help nature recover after a fire roars through. “In many of our areas, many wildlife species are in distress. It doesn’t matter if it’s yellow-legged frog, sage-grouse, spotted owl, mule deer or blacktail – it’s important our organization works for all of them,” she said. “We look at ourselves as being a part of the environment.  We have a role in stewardship so we can’t just throw our hands in the air and walk away. We’re in a different position than we were before 40 million people lived in California.”

On the Slinkard/Little Antelope site, mechanical seeding involving tractors was conducted where access was possible. In areas of the property that are too steep for tractors to operate, aerial seeding was employed. Johnson is hoping that weather, a variety of approaches and repeated treatments over the three-year term of the project will contribute to its success.

“We are sort of at the whim of the weather. We waited until we saw precipitation in the forecast (last November) and we lucked out. We managed to get the seed down right before the first winter storm and a lot of it got buried under snow, so I think we’re likely to get good germination,” said Johnson.

The work being done at the Slinkard/Little Antelope Wildlife area is just one of many wildfire resiliency projects CDFW is implementing across the state, aimed at improving the ecological resiliency of its wildlife areas, ecological reserves and the surrounding communities from potential wildfires. Managing wildfire resilience requires a landscape-scale perspective that is made possible by developing partnerships with other organizations, such as CDA, that share a common goal.

By CDFW Information Officer Tim Daly

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Faded black and white photos are all that’s left of the Owens River Gorge’s glory days as a trophy brown trout fishery. Biologists expect the fish to make a comeback following near-annual pulse flows that begin in September to improve habitat.




CDFW crews electrofish the Owens River Gorge two times per year to assess the health of the river’s brown trout.

From boom to bust to decades of angler indifference, few California fisheries have experienced such wild swings of fortune as Mono County’s Owens River Gorge.

The latest chapter in the long saga of the Gorge unfolds this month when the Los Angeles Department of Water and Power (LADWP) sends a relatively brief burst of water known as a “Channel Maintenance Flow” down the 10-mile stretch of river between the Upper Gorge Power Plant and Pleasant Valley Reservoir to benefit fish habitat.

From Sept. 9 to Sept. 17, water flows will rise from the relatively placid 35 to 55 cubic feet per second (cfs) typical in the Gorge to 680 cfs before gradually ramping back down. Access to the Gorge will be closed by LADWP during the nine-day “pulse flow” event for public safety.

The temporary boost in water flow represents the successful resolution of decades of legal battles involving LADWP, Mono County and CDFW. The high flows are expected to breathe new life into the Owens River Gorge ecosystem and its once-storied brown trout fishery. Court settlements mandate the pulse flows continue almost annually -- 18 out of every 20 years.

The flows are intended to replicate seasonal scouring that occurred naturally in the Gorge long before dams, power plants and water diversions were constructed in the last century. In fact, these alterations dried up the Owens River Gorge from 1953 to 1991 until years of litigation restored some minimal flows and attempts to restart a once-fabled brown trout fishery.

The Owens River Gorge is paradoxical – so close yet so far away. Just northwest of Bishop and within sight of Highway 395, it is difficult to access with limited and steep trails to reach its waters 500 to 900 feet below the rim. Since water returned to the Owens River Gorge in 1991, it has been more popular with hikers and rock climbers than trout anglers.

It was a much different story prior to the construction of the Long Valley Dam in 1941, which created Crowley Lake, and the subsequent addition of a number of power plants along the stretch of river. Before then, the Owens River Gorge was a destination brown trout fishery with a worldwide reputation. So good was the fishing it was one of the few waters in California with limits based on weight – 25 pounds plus one fish per angler per day.

CDFW Environmental Scientist Nick Buckmaster is based in Bishop and conducts twice-yearly electrofishing surveys in the Gorge along with macroinvertebrate sampling.
“Right now, the fish populations are pretty stunted,” Buckmaster said. “We just don’t have large brown trout in the Gorge anymore.”"

The Gorge is home almost exclusively to wild brown trout and the populations are high. Buckmaster estimates between 1,500 to 5,000 trout per mile, numbers that compare favorably to many blue-ribbon trout fisheries in the state.

“The problem is they are all small. Their growth really slows down around 5 inches, and most of the fish in the Gorge are less than 8-inches long. Their growth really plateaus,” he said. “By the time they get to 8 inches, they are geriatric fish.”

Buckmaster explained that brown trout undergo an important life change once they reach between 8 and 14 inches in size. They mostly stop eating aquatic insects and transition into apex predators, preying on other fish and just about anything else of substance they can eat. The diet change leads to rapid growth and turns them into a prize for any trout angler skilled enough to catch them.

Plateauing at 5 inches, however, most of the brown trout in the Owens River Gorge never reach that important developmental milestone or achieve it only toward the end of their lives.

“If you want big brown trout, they need something to eat,” Buckmaster said. “And they usually need a lot of something to eat.”

CDFW fisheries biologists expect the pulse flows to provide just that by dramatically altering the ecosystem. The big burst of water will scour pools and restore the deep-water holding and ambush habitat needed by large brown trout. The flows will flush out years of accumulated sediment, exposing gravel beds critical for trout breeding while fostering a broader diversity of aquatic life than what’s present in the Gorge today.

Mayflies and stoneflies are largely absent from the ecosystem, and caddisflies – safely encased and underneath rocks in their larval stages – provide a limited food source. Small populations of native Owens suckers exist in the Gorge. Their numbers are expected to grow with an increase in aquatic insect life following the pulse flows, incidentally providing important forage for growing brown trout.

The high waters will inundate and benefit riverside riparian growth, offering shade and cover and additional insect habitat. The flows also are expected to flush out invasive  New Zealand mud snails that have infested the Gorge over time. The snails provide little benefit to fish and are a source of competition for other macroinvertebrate life.

Buckmaster said biologists could see positive changes in the Gorge as quickly as three months after the flows. And bigger brown trout could start turning up in Buckmaster’s electrofishing surveys – and at the end of anglers’ lines – as early as next year.

CDFW Photos. Top Photo: CDFW scientific aids Christi Kruse and Emma Hewitt identify some of the macroinvertebrate life taken from the Owens River Gorge.

A long, wet winter has been good for Junction Reservoir and CDFW’s Kamloops rainbow trout that live there.


The June Lake Marina graciously offered up its net pens to CDFW’s Kamloops rainbow trout program when the drought forced CDFW to rescue its brood stock from a shrinking Junction Reservoir.


CDFW hatchery staffers Jimmy Sparks, left, and Drew Klingberg prepare to sex and sort Kamloops brood stock for later spawning, separating males from females as well as those females ready to spawn immediately versus those that need more time to ripen. The fish are returned to Junction Reservoir after spawning.


The offspring from these Kamloops will be raised at CDFW’s Fish Springs Trout Hatchery and stocked by airplane as fingerlings into backcountry waters across the state approved for trout stocking.


Resplendent in their spring spawning colors, Kamloops rainbow are raised and bred for their hard-fighting ability and wild nature that allows them to thrive in California’s remote backcountry waters and provide a thrill for anglers who catch them.

Junction Reservoir in Mono County is CDFW’s brood lake for the Kamloops rainbow trout, a hard-fighting strain originally from the Kamloops region of British Columbia.

The 20-acre lake sits on a private cattle ranch off-limits to fishing. It provides a secluded setting for the brood stock, whose progeny are used almost exclusively for the aerial stocking of backcountry waters throughout the state.

“We try to keep them raised in a more wild condition so they do better in the wild,” said Hot Creek Trout Hatchery Manager Mike Escallier. “They are a really fun fish to catch. They jump a lot. They will jump 3 feet out of the water when you hook one.”

And Junction Reservoir has never looked better. This spring, the lake was filled to the brim after a long, cold, wet winter. Near the mouth of the lake’s one small inlet, Kamloops were staging for a spawning run, their feisty nature on full display in the clear waters, breaking the surface occasionally and fighting each other over territory.

Kamloops further up the inlet were blocked from moving upstream by a concrete and metal trap. That’s where CDFW’s hatchery staff collect and sort the fish each spring, spawning them manually to produce the offspring that will be deposited as fingerlings this summer by airplane into backcountry waters approved for stocking.

The entire scene is a welcome sight after California’s drought nearly collapsed CDFW’s backcountry fish-stocking program. During the darkest days of the drought, the small inlet feeding into Junction Reservoir dried up. Combined with the years-long shortage of rain and snow, Junction Reservoir withered to about half its size. In 2013, CDFW conducted an emergency fish rescue to save about 2,000 of the brood fish and its backcountry trout stocking program altogether.

The rescued fish were relocated to CDFW trout hatcheries and other nearby waters for safe-keeping. The owners of the June Lake Marina provided a major assist, offering up some of their net pens on June Lake to CDFW and its Kamloops at no charge. The June Lake net pens continue to hold some Kamloops, which CDFW spawns each spring until the program transitions back fully to Junction Reservoir and CDFW’s Fish Springs Trout Hatchery south of Big Pine where the baby Kamloops are raised.

CDFW returned brood fish to Junction Reservoir in the spring of 2017 following a wet winter and heavy snowpack. CDFW is rebuilding production toward its annual goal of collecting and fertilizing 1.4 million eggs. Some of the offspring are put back into Junction Reservoir to add genetic diversity and different age classes to the rebuilding brood population as no natural spawning occurs in the lake.

One benchmark hatchery managers and biologists are striving toward is the return of Kamloops to Crowley Lake, where more anglers will have a chance to enjoy them.

Before the drought wreaked havoc on CDFW’s Kamloops program, a portion of the Kamloops produced each year were allocated to Crowley Lake. While the backcountry trout are sterile – or “triploid” – the fish stocked into Crowley are “diploids” capable of spawning naturally.

“They spawn at different times than other strains of rainbow trout,” explained Escallier. “They give anglers fishing the creeks opportunity. They tend to be running up the creeks from Crowley right around the trout opener.”

CDFW Photos. Top Photo: The inlet to Junction Reservoir is blocked by a fish trap where CDFW hatchery employees catch fish in the spring for spawning.

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Media Contact:
Peter Tira, CDFW Communications, (916) 322-8908

Lahontan cutthroat trout are a Crowley prize. In addition to natural spawning that occurs in the lake, CDFW plants the fish as fingerlings in the fall. By the spring opener, many like this fish are resplendent in their spawning colors.

Jim Erdman conducts creel surveys to see how many trout CDFW planted last fall turn up on opening day. Fish 15 inches or longer are determined to be from last fall's stocking when they were planted as fingerlings.

Mark Risco from Temecula shows off the 20-inch brown trout he caught opening day at Crowley Lake. In addition to natural spawning, CDFW's Hot Creek Hatchery stocks thousands of brown trout each year, which are very popular with Crowley anglers.

CDFW volunteer Carl Ronk conducted opening day creel surveys at Crowley Lake along with CDFW Environmental Scientist Jim Erdman.

Mono County’s Crowley Lake is a destination fishery that attracts trout anglers of all kinds – bait fishermen, lure casters, trollers and fly anglers – throughout the state during its open season.

The sprawling lake, situated at 6,700 feet and covering some 5,300 surface acres in the Eastern Sierra, also represents a huge investment for CDFW. The nearby Hot Creek Trout Hatchery raises hundreds of thousands of rainbow, brown and Lahontan cutthroat trout for Crowley each year that provide the backbone of the quality angling experience. Many of the fish are stocked as fingerlings in the late summer or fall and grow rapidly in the invertebrate-rich environment. Some go on to spawn in the lake’s many feeder creeks and supply wild progeny to the population.

All of which helps explain why CDFW Environmental Scientist Jim Erdman has been out conducting creel surveys at Crowley every opening day since joining CDFW in 2005. Based in Bishop, Erdman’s goal is to contact at least 300 anglers and see which hatchery fish are turning up in their catch, in what numbers, in what proportion of species, and in what condition. The report is an annual check to see whether CDFW’s management plan for Crowley remains on point or whether adjustments need to be considered. The opening day creel surveys have been taking place since 1997 when CDFW biologist Curtis Milliron wrote the Crowley Lake Management Plan.

CDFW volunteer Carl Ronk assisted Erdman this past opener April 27. The two split up at times – one checking anglers along the shoreline, the other awaiting returning boats to the Crowley Lake Fish Camp marina, the only formal boat launch at the lake.

Their tools for the day included a clipboard for note-taking and a 15-inch wooden “Crowley Stick” for measuring fish. CDFW biologists have determined that a fingerling trout stocked in the fall should be 15 inches or greater by opening day in the nutrient-rich waters. Erdman typically completes and submits his report by the afternoon of the opener and shares it with anyone interested. Local papers have been known to reprint it in its entirety.

For the 2019 Crowley opener, the creel survey found shoreline angler success was greatly improved from the previous year with an average catch per angler of 3.66 trout compared to last year’s average of just 0.71 trout. Overall, however, catch rates and total catch per angler were lower than 2018. Fish size was also down. Approximately 41.4 percent of the rainbow trout measured were greater than 15 inches, well below the annual average of around 70 percent. The catch rate fell below CDFW’s management goal of one fish per angler for each hour of effort.

A long, cold winter and late ice-out were cited as factors in a slower-than usual Crowley opener and smaller fish with less time to fatten up post ice-out.

“Crowley Lake did not ice-out until April 10, 2019, and this kept fish in deeper water than usual,” Erdman wrote. “No fish were seen in the McGee, Crooked or Whiskey Creek inlets and few to no fish were seen staging for a spawning run. Water temperatures in the inlets remained below 40 degrees.”

Rainbow trout made up the majority of the catch followed by brown trout. Lahontan cutthroats were scarce. CDFW annually stocks 100,000 Lahontan cutthroat fingerlings in the fall. Cutthroats represented just 0.9 percent of the shoreline catch and 1.6 percent of the boating catch compared to 2018 findings of 11.3 percent of the shoreline catch and 2.2 percent of the boating catch.

Opening day on Crowley Lake, with its big crowds and festive atmosphere, has always been about more than bag limits as reflected in Erdman’s creel survey report.

“Returning boat anglers were a bit slower than usual coming in off the lake probably due to the pleasant conditions on the lake. Relaxing in the sun and drifting in the slight breeze. A grand day to be on the water.”

CDFW Photos. Top Photo: CDFW's creel surveys play an important role in evaluating the lake's management and stocking allocations.

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Media Contact:
Peter Tira, CDFW Communications, (916) 322-8908