Science Spotlight

  • September 17, 2021
burned landscape after low severity fire

As Californians continue to face devastating wildfires, researchers are lending their expertise by producing data to inform fire policy.

CDFW contributed an article to a recent special-edition journal featuring fire studies from around the world. CDFW’s paper shows that a mix of fire intensities, and low severity fires in particular, promote a diversity of forest carnivores like bears, fishers and bobcats. The results of the study support the value of prescribed burning in advancing ecological and societal objectives including wildlife diversity and human health and safety.

“Wildfire is a natural part of the landscape, and we probably can’t stop it,” said the paper’s lead author, CDFW Senior Environmental Scientist Dr. Brett Furnas. “But prescribed burning is a tool we have to mimic low severity fires, which are less destructive. It’s a win-win because low severity fires have the added benefit of improving biodiversity.”

Dr. Furnas and his team conducted the research by analyzing data from 1,500 camera traps that have been placed by scientists in Northern California forests since 2009.

“We pulled together a large data set and compared the occurrence of 15 species of forest carnivores — including bears, fishers and bobcats — to the fire history of the landscape during that time period. The study shows our forest carnivores are well-adapted to low severity fires,” said Furnas.

Unlike high intensity fires which tend to eradicate all trees in a given area, low intensity fires tend to thin out forests and burn mostly the understory. Prescribed burning mimics the effects of low intensity fires which are associated with ecological benefits. Other research has shown that mixed intensity fires in California have ecological benefits for birds, bees and plants.

“The goal of the study was to use science to help inform conservation decisions,” said Furnas. “The science can help policy makers decide the best course of action and how to balance the needs of the state.”

Media Contact:
Ken Paglia, CDFW Communications, (916) 825-7120

Categories: Science Spotlight, Wildlife Research
  • June 22, 2021
monarch butterfly on a milkweed leaf

A male adult monarch on a milkweed leaf

Scientist Hillary Sardiñas, who works as CDFW’s pollinator coordinator in the Wildlife Diversity Program, recalls a moment several years ago when she showed her young daughter a monarch caterpillar, and realized it’s a species her daughter might not grow up to enjoy.

“It really hit home in a personal way how important it is to conserve the species,” said Sardiñas.

The population of migratory western monarchs has declined more than 99 percent since the 1980s when millions overwintered in groves along the California coast. By the mid-2010s, the population had dropped to the hundreds of thousands. Just a few years ago, scientists estimated there were only 30,000 left. Now there are only about 2,000 migratory western monarchs left statewide.

“Western monarchs may be headed toward extinction in California, and we need to take drastic and immediate action to help recover the population,” said Sardiñas.

Western monarchs overwinter along the California coast from San Diego to Mendocino County, expanding during springtime along the Central Coast and Central Valley. They ultimately migrate into other states west of the Rocky Mountains to breed.

The drastic population decline has been attributed to several factors including habitat loss, climate change and exposure to pesticides. Western monarchs’ overwintering habitats continue to be destroyed or altered by human development, especially along the Central Coast. Development is also reducing nectar resources. Climate change may be causing monarchs to leave overwintering sites earlier than usual and before milkweed, their host plant, has fully bloomed. This causes what scientists call a “phenological mismatch,” meaning monarchs at times don’t have a place to lay eggs and lack the ability to create the next generation in their multi-generational life-cycle.

In addition to population decline, scientists are seeing a new and possibly dangerous phenomenon—an increase in resident monarchs that remain along the coast year-round and don’t migrate. These monarchs are encouraged to stick around by a non-native milkweed which allows them to breed all throughout the year. The phenomenon might seem like a novel adaptation, but scientists are finding that resident monarchs can have up to 10 times the occurrence of a protozoan parasite known as OE (Ophryocystis elektroscirrha). OE can be transmitted through contact with milkweed leaves, and leads to wing deformation, poor health, decreased reproductive ability or death.

To conserve the population, CDFW is taking action on several fronts:

  • In partnership with the Western Association of Fish and Wildlife Agencies, CDFW helped develop a 50-year management plan for western monarch conservation, published in 2019. Two major focus areas of the plan are management of overwintering sites on the California coast and restoration of breeding and migratory habitat in the Central Valley.
  • In partnership with nonprofit River Partners and with funding from the Wildlife Conservation Board’s Monarch Butterfly and Pollinator Rescue Program, CDFW is restoring and enhancing 500 acres of land for monarchs and pollinators in the Central Valley.
  • On its properties throughout the state, CDFW is enhancing and restoring 1,500 acres of habitat for pollinators and monarchs through management actions and planting milkweed and nectar plants.
  • CDFW is improving management strategies on four department-owned overwintering sites.
  • CDFW is increasing milkweed availability for habitat restoration projects by collecting seed from our properties and partnering with local nurseries.
  • CDFW is also helping coordinate conservation action among stakeholders by participating in the Rangeland Monarch Working Group and co-leading the Monarch Plant Materials Working group with the Xerces Society for Invertebrate Conservation.

Julea Shaw, an environmental scientist in CDFW’s Lands Program, helps coordinate the department’s conservation and restoration efforts. Through her work, she is often reminded how California residents have a personal connection to the western monarch species.

“I speak to so many people who remember growing up seeing thousands of monarchs. It shows how impactful the species can be and how they capture peoples’ imaginations,” said Shaw.

There are several actions that residents can take to help conserve western monarchs.

First and foremost, residents can help by planting locally native milkweed and nectar plants. When choosing nectar plants, conservationists recommend choosing plants that bloom in early spring and late fall when resources tend to be scarce.

Second, residents can help by reducing or eliminating pesticide use in their own gardens.

Third, monarch enthusiasts can help conservation efforts by participating in community science projects. There are multiple organizations which train volunteers to count western monarchs at overwintering sites. In fact, much of the current data on declines in western monarch populations was collected in part by community scientists.

Finally, a note on captive rearing. CDFW would like to remind California residents that a scientific collection permit is required to handle and/or conduct research on western monarchs. Rearing monarchs without proper training can lead to health problems that further exacerbate the species’ decline. Recent research shows that captively reared monarchs can be weaker, have smaller wingspans, and be less adapted to migrate.

“It’s going to take a collective effort between residents and conservation scientists to turn the species around. We’re diligently working to expand our efforts—but the work won’t be done anytime soon,” said Sardiñas.

CDFW Photo

Categories: Science Spotlight
  • June 21, 2021
Scientist, Michael Mammola holding a fish on a lake with blue sky

Michael Mamola, CDFW’s Statewide Trout Management and Stocking Coordinator, shows off a Lahontan cutthroat trout before its release into Echo Lake earlier this spring.

hand holding a fish for release in a lake
The Lahontan cutthroat trout is the largest inland trout species in the world and the only trout native to the Lake Tahoe Basin.

Visitor fishing off the side of a pier in a lake
Few visitors to Echo Lake pause to fish and probe the waters for the Lahontan cutthroat trout that live within.

fish in a lake
Lahontan cutthroat trout grow large in Echo Lake, El Dorado County, thanks to the large population of forage fish, principally the Lahontan redside minnow.

California anglers looking to target the native but elusive Lahontan cutthroat trout may want to put Echo Lake in El Dorado County on their summer itinerary.

For the past several years, the California Department of Fish and Wildlife (CDFW) has managed the deep blue waters of Echo Lake exclusively as a Lahontan cutthroat trout sport fishery.

That’s the same fish that has turned Nevada’s Pyramid Lake and its monster-sized cutthroats into a global fishing destination and created a cult following at Heenan Lake in Alpine County among fly anglers looking to tangle with a trophy cutthroat.

Located just minutes off U.S. Highway 50 near South Lake Tahoe at an elevation of 7,500 feet, Echo Lake may offer California anglers their best chance to encounter the Tahoe Basin’s native trout species given the combination of an easy drive, a plentiful fish population supported through a generous stocking regimen, and wide-open fishing access without the restrictions on seasons, take or tackle methods found at some other Lahontan cutthroat trout fisheries.

Adding to the overall experience, Echo Lake receives relatively little fishing pressure. The 300-acre lake is best known as a jumping-off point for the southern portion of Desolation Wilderness. Few of those backcountry travelers, however, pause to wet a line at Echo Lake.

“It’s sort of a hidden gem,” says Mitch Lockhart, CDFW’s District Fisheries Biologist for El Dorado, Placer and Nevada counties. “You’ll not be combatting for space to fish here.”

Echo Lake received a recent stocking of 100 brood stock Lahontan cutthroat trout from nearby Heenan Lake. Resplendent in their crimson spring spawning colors, the fish ranged in size from two to nine pounds with an average weight of two to three pounds. CDFW followed up that trophy stocking with a plant of some 20,000 “sub-catchable” Lahontan cutthroat trout in the seven- to nine-inch range.

Echo Lake’s recent history as a Lahontan cutthroat trout fishery resulted from a collaboration between lakeside property owners and CDFW. Cabin owners were seeking improved fishing opportunities given recent cutbacks and elimination of hatchery stockings of rainbow trout, brown trout and brook trout. At the same time, CDFW fisheries biologists were looking for suitable locations to stock Lahontan cutthroat trout into their historic range in the Tahoe Basin and expose more anglers to the unique, native fish.

Echo Lake fit the criteria. Its steep-sided granite cliffs, clean, cold deep waters are reminiscent of Independence Lake in Nevada County and Fallen Leaf Lake in El Dorado County, two historic and active Lahontan cutthroat trout fisheries.

Echo Lake also is relatively isolated from other waters and protected from infiltration by non-native trout species. The lake holds some small, remnant populations of brook and brown trout with little opportunity for wild rainbow trout to access the lake and colonize it from surrounding waters. Displacement, hybridization and competition from non-native trout is largely what earned the Lahontan cutthroat trout listing under the federal Endangered Species Act 51 years ago and what mostly prevents large-scale recovery efforts today.

And unlike some other high Sierra lakes where trout eke out a meager existence in near-sterile conditions, Echo Lake is rich with food in the form of the Lahontan redside, a native minnow that has proven an important forage fish responsible for Lahontan cutthroat trout growth rates of two to three inches a year in Echo Lake.

Anglers reported catching Lahontan cutthroats to 26-inches last year with the average size being closer to 12 to 14 inches with an occasional 16-, 18- and 24-inch fish in the mix. CDFW biologists say they are seeing anecdotal evidence of natural spawning, but plan to manage Echo Lake primarily for recreational fishing and not species recovery.

CDFW has stocked two strains of Lahontan cutthroat trout into Echo Lake, the Pilot Peak strain of Pyramid Lake fame that can reach sizes in excess of 20 pounds, and the smaller Independence/Summit Lake strain of fish from eggs collected at Heenan Lake and raised at the American River Trout Hatchery outside of Sacramento.

A Lahontan cutthroat trout caught and documented from Echo Lake qualifies for CDFW’s Heritage Trout Challenge, which incentivizes and rewards anglers for catching six different forms of California native trout from their historic drainages.

In addition to easy drive-to access, Echo Lake features a popular marina, boat launch and convenience store where kayaks and canoes can be rented. Private boats and other waterfcraft can be launched only after mandatory inspection and certification that they are free of aquatic invasive species.

CDFW Creates Lahontan Cutthroat Trout Sport Fishery at Echo Lake (Video)

CDFW Photos:

Categories: Science Spotlight
  • May 14, 2021
bobcat on a dirt path

Young bobcat photographed for project, San Diego County

four scientists observing bobcat scat on a dirt path - click to enlarge in new window
Bobcat project staff (left to right) Liam Jasperse-Sjolander, John Nettles, Rudolplh Mena, Jessica Copeland using stick in process of determining if scat came from bobcat

bobcat trail camera on a dirt path with brush - click to enlarge in new window
Bobcat project camera station, Inyo County

bobcat in the snow with brush - click to enlarge in new window
Bobcat in snow, San Diego County

bobcat in sandy path with brush - click to enlarge in new window
Bobcat in sandy terrain, San Diego County

In the field of wildlife management, one of the most common and sometimes most difficult tasks is to obtain information about a particular species of animal in order to properly manage that species. The California Department of Fish and Wildlife (CDFW) was recently tasked by the State Legislature to conduct a demographic study of a particular species of animal that is known to be elusive and generally secretive, bobcats (Lynx rufus).

Officially known as the California Statewide Bobcat Population Monitoring Project, the study is happening because of a bobcat hunting ban that took effect in 2020. Part of the legislation requires the issue be revisited in 2025, but only after CDFW conducts a statewide population assessment, which will then lead to a science-based bobcat management plan.

Performing this study is complicated by a short timeline due to funding and personnel issues. Because the funding and the positions for those hired to conduct the study both end on June 30, 2022, the challenges of accomplishing this study become even greater. The effort began with forming the Bobcat Management Oversight Group (BOMOG), comprised of key individuals from around the state. That team includes the Deputy Director of Wildlife and Fisheries, the Chief of the Wildlife Branch, and key Regional and Program Managers. The BOMOG quickly realized that for the study to be successful, they would need to bring together a team of individuals from around the state. This resulted in the formation of the Technical Advisory Group (TAG), comprised of some of the top scientists and researchers within CDFW.

“The two groups will ensure project staff are employing consistent field protocols and methods, so the project is a success,” said Wildlife and Fisheries Division Deputy Director Stafford Lehr. “Instead of one unit being responsible, the entire department is responsible for this project.”

The TAG was asked to quickly (within two months) develop a study plan to guide the implementation of the study. The group not only met that deadline but also provided a draft capture plan as well as planned and initiated a pilot project to test the plan prior to its full implementation.

“The TAG’s accomplishments in this very short timeline are a testament to their talent and dedication,” said South Coast Regional Wildlife Program Manager and TAG project lead Rick Mayfield. “This project would not have been possible without their hard work.”

With the planning process completed, CDFW hired a team of 20 people specifically for the project. One was Senior Environmental Scientist Rachel Roberts who, as the lead over this group, faces the challenge of implementation and completion of the study by June 30, 2022. At that point, the data collection will end, and the analysis and creation of a statewide bobcat management plan will begin. This plan, due to be completed by January 2025, will cover all aspects of bobcat management, from demographic information to the effects of habitat loss, wildfires and urbanization on the species.

“It’s kind of funny because we know a lot about bobcats and nothing at the same time,” said Roberts.  “We see them in a lot of places and we think that they tend to do well on the edges of urban areas. There have been projects across that state that have collared bobcats, so we have some idea of a home range, but we don’t know specifically all of the different habitats they’re residing in. We have anecdotes of them in orchards, or at high elevations, but that’s one study in one area. This project is trying to get truly to where bobcats are and where they aren’t.”

A few things we do know about bobcats in California: they’re about one fourth the size of a mountain lion, weighing between 12 and 25 pounds depending on environmental conditions. They prey on rabbits, rodents, birds, insects, reptiles and occasionally chickens. Their current population is estimated between 70,000-100,000 statewide. Pelage (fur) markings on their body, legs and face make it possible to distinguish one from another.

To get the most accurate information on California’s bobcat population, Roberts and her team will collect scat samples for fecal DNA analysis. This analysis allows for the individual identification necessary for determining population size via a capture/recapture model. Complementing the scat analysis in assessing the bobcat population, the teams will gather data and photographs in 48 different study areas. Each study area will be 40 square kilometers (just over 15 square miles) and have 80 cameras mounted to record still images of anything that moves in that area, day and night. The motion-activated cameras will shoot images in each study area for six weeks, before being relocated to the next study area.

“We're taking a three-shot, rapid-fire burst with two cameras facing each other at each camera station,” said Roberts. “We're hoping to be able to get photos of the pelage patterns on each bobcat, especially on the insides of their legs – that’s how you can really identify individuals. We're hoping to see these cats more than once so that we may be able to run the capture/recapture model to estimate bobcat density with the camera data as a complement to the scat data.”

“To get their densities and to be able to keep track of individual bobcats, so we know we’re not double-counting them, the DNA in scat is definitely the gold standard,” said Brett Furnas, a biostatistician with the CDFW Wildlife Investigations Lab. “If it’s not a bobcat sample we’re collecting it might be a coyote instead. We confirm that with genetic analysis to make sure what we’re counting is indeed from a bobcat, so we can determine individuals to count them.” Furnas is no stranger to this kind of work. “I’ve worked a lot on deer, so this method of going around and picking up bobcat scat is what we first applied to deer,’ he said. “I’ve also been working with Justin Dellinger (lead of CDFW’s mountain lion monitoring project), so this is the third project in which we’re using genetic information.”

There’s one key difference between the gathering of scat DNA and taking of photographs. Project team members will control how much scat they gather and submit for DNA analysis. Team members won’t have control of the amount of photos that are taken by the nearly 500 hundred motion-activated cameras scattered around the state. The number of photographs to sort through and categorize would be overwhelming, if not for a new company, Wildlife Insights, which stores the images and identifies the animals photographed in the study area.

“All of those photos are uploaded to the cloud and when you open the interface, it has already tagged the animals,” said Roberts. “If it sees turkeys, it has already tagged it. We’re just going in and making sure it’s correct. And, you can just pull out the species that you are interested in. Before, this was all super clunky. We did a pilot study and there were hundreds of thousands of photos, just from two cameras set up for eight weeks.”

Roberts said she’ll visit most of the study areas over the course of the study, but she’d be perfectly happy making it to all 48. The challenge of measuring California’s bobcat population is exactly what she wants to be doing.

Deputy Director Stafford Lehr sees the importance of this work for years to come. “We are striving for a more cohesive approach to applied management throughout the department and we hope this is an improved method of program delivery,” he said. “The importance of having a robust management plan that withstands scientific review and public scrutiny will pay dividends in future programs for the department.”

CDFW Photos

Categories: Science Spotlight
  • May 10, 2021
Bear in a tree

A female black bear takes in her surroundings from the safety of a pine tree after being trapped, tagged and hazed by state parks and wildlife personnel last fall.

As the Lake Tahoe Basin’s black bears emerge from their winter slow-down and slumber, campground managers, biologists, park rangers and wildlife officers hope to have a new tool at their disposal to help manage the human-bear conflicts certain to arise this spring and summer: a growing catalogue of Tahoe’s bear population.

Since the fall of 2019, the California Department of Fish and Wildlife (CDFW) and California State Parks have teamed up to trap, tag and haze as many Tahoe bears as possible to identify individual bears, build a genetic database of the population, study its overall health, and whether related bears are passing down problem behaviors from one generation to the next. Eighteen bears have been trapped to date – four of those being recaptures. Genetic material is collected and each bear is outfitted with an identifying ear tag before release.

This May, CDFW will broaden the effort and team up with the U.S. Forest Service to trap, tag and haze additional bears within the Tahoe National Forest. The trapping takes place in short windows during the early spring and late fall off-seasons at Tahoe-area campgrounds. The bears are hazed – but not harmed – upon release to provide a negative human interaction and to see whether the experience will keep them away from campgrounds and people in the future.

In this video, Shelly Blair, CDFW’s wildlife biologist for El Dorado and Alpine counties, and Sarinah Simons, California State Parks Sierra District human-bear management specialist, explain the innovative collaboration and scientific work during trapping efforts last fall.


CDFW Photo

Categories: Science Spotlight
  • May 6, 2021
tractor plowing a field preparing the field to plant

A three-acre field is planted with a combination of sunflower and safflower seeds to provide food for mourning doves – and a place for dove hunters to hunt come Sept. 1.

Scientist Brian Young sitting in the back of a truck with seeds
Oroville Wildlife Area Manager AJ Dill sits on the back of a flatbed truck stacked with sacks of safflower and sunflower seed and fertilizer for the spring planting season.

Scientist Brian Young holding soil in a field
Fish and Wildlife Technician Brian Young holds handfuls of safflower and sunflower seeds prior to planting.

Field of safflower and sunflower seeds
Upland habitat planted in the fall is lush and colorful in the spring providing important nesting habitat for wild mallards and Canada geese near the shores of the Thermalito Afterbay.

It only took Brian Young about two laps around the freshly plowed, three-acre field before the red-winged blackbirds started showing up.

A fish and wildlife technician at the Oroville Wildlife Area in Butte County, Young was piloting a John Deere 5075M utility tractor along the shores of the Thermalito Afterbay in mid-April, scattering a mix of sunflower and safflower seeds behind him. The red-winged blackbirds were taking full advantage of the easy meal.

Once seeded, Young would retrace his route, distribute fertilizer and hope for the best. A quarter-mile away along a gently sloping hillside another John Deere tractor was at work covering up with soil another plowed, seeded and fertilized field.

Spring is planting season at the 12,000-acre Oroville Wildlife Area and at dozens of other California Department of Fish and Wildlife (CDFW) properties up and down the state as crop fields are prepared for mourning doves – and the dove hunting season that begins in September. And while planted to attract doves and provide public land dove hunting opportunities, the crop fields also will provide food and habitat for all manner of wildlife, including those red-winged blackbirds.

“Native songbirds, tricolored blackbirds, wild turkeys – you name it. Just about anything that flies – with the exception of our raptors – will be out here feeding in these fields throughout the fall,” explained AJ Dill, the Oroville Wildlife Area manager since 2013.

Safflower and sunflower are mourning dove favorites. A couple weeks before the Sept. 1 dove season opener, the Oroville Wildlife Area’s tractors will be back to knock down the safflower and sunflower stalks and scatter the seeds to the ground where doves can access them more easily.

Mourning doves are especially attracted to harvested agricultural fields and the food plots at Oroville and other CDFW properties can provide fast action for public land dove hunters on opening day and places to hunt throughout the season. At Oroville, however, hunters have to do their homework. Unlike some other wildlife areas, Oroville does not provide hunting maps or directions to its dove fields. Hunters have to scout and find them on their own. A Type C wildlife area, Oroville is open daily to dove hunting during California’s two dove seasons. No special permits, reservations or fees are required provided hunters are otherwise properly licensed.

This spring, the Oroville Wildlife Area will plant about 60 acres of safflower and sunflower among 16 different fields varying in size throughout the wildlife area. The dove fields are spaced out to spread out the hunters, prevent overcrowding and foster safer hunting conditions.

How productive the fields ultimately become will depend on many factors – but none more so than weather.

“Everything we do out here is dryland farming. We don’t irrigate. So we really need a shot of water – just a little bit of rain – to get things going,” Dill said.

A significant portion of the Oroville Wildlife Area’s upland habitat work also takes place in the fall when 80 acres of nesting cover are planted annually – typically some combination of vetch, barley, peas, wheat, oats, clover and grasses – along the shores of the Thermalito Afterbay to benefit nesting ducks and geese in the spring. The wildlife area maintains about 240 managed acres of upland nesting habitat in total, the dense cover providing nesting hens, their eggs and newborns safety and protection from predators.

As with the planted dove fields, the lush, colorful, nesting habitat provides secondary benefits to other grasslands-dependent species, particularly pollinators such as bumblebees, honeybees and butterflies. The loss of grassland and upland habitat throughout California has contributed to the decline of wild mallards, wild pheasants, pollinators and other species and adds a sense of urgency and heightened importance to the upland habitat work at the Oroville Wildlife Area and other CDFW properties throughout the year.


CDFW Photos

Categories: Science Spotlight
  • March 29, 2021
Buena Vista Lagoon surrounded by dry grass with blue sky

Buena Vista Lagoon Ecological Reserve, San Diego County

Mouth of the Buena Vista Lagoon bordered by rocks and cloudy sky
Mouth of Buena Vista Lagoon

Buena Vista Lagoon weir bordered by a wooden wall and trees
Weir near the mouth of Buena Vista Lagoon

cat tails weeds in Buena Vista Lagoon
Cattails growing on edge of lagoon

Buena Vista Lagoon sign #Free The Lagoon Saltwater Heals Naturally
Sign encouraging the reopening of lagoon

The Buena Vista Lagoon Ecological Reserve in San Diego County sits between the cities of Oceanside to the north and Carlsbad to the south. It’s historic because it was the state’s first-ever reserve, created in 1968. Recently it has become considered noteworthy, if not historic, for another reason. Homeowners in that area, the San Diego Association of Governments (SANDAG), CDFW and several other groups came to an agreement after years of dispute on how the lagoon should be altered so it thrives well into the future.

“It’s a really exciting situation, and it leads me to believe that people will do the right thing when push comes to shove and not just look out for their own personal interests,” said CDFW Reserve Manager Gabriel Penaflor.

“To me, it's a good-news story in terms of bringing polarized stakeholders that had disparate views, together to say, we are now moving forward together,” said Planner Keith Greer of SANDAG.

“It’s been a contentious issue for decades,” said Buena Vista Audubon Executive Director Natalie Shapiro. “It’s just wonderful that we’re all on the same page.”

Like lagoons up and down that part of San Diego County, Buena Vista took in runoff from hills to the east and fed water to the west into the Pacific Ocean. But in the ‘40’s a weir was added at the mouth by nearby landowners, so the lagoon essentially became freshwater only. In the ‘70’s that weir was replaced with an even stronger blockage that made the lagoon even more like a lake, and not a body of water with an ocean connection.

But what may have been a beautiful sight for residents, became an environmental, health and flooding concern for others. As the lagoon grew increasingly shallow because of increasing sediment and silt, cattails exploded in growth, taking away about 60 acres of open water over the last 30 years. Over the next 30 years the entire lagoon would more likely resemble a marsh as the open water areas as sediment continued to rise and vegetation continued to spread. Fresh water and thick cattails also bring another problem.

“There's a large mosquito breeding ground in the lagoon and a lot of that has to do with all the cattails there, so a big concern is public health,” said CDFW’s Penaflor. “The cattails are just choking out the lagoon. They’re so big and thick they stop the larvicide that the county drops from reaching the water and affecting the mosquito larva. It’s a very arduous process to remove the cattails – they come back very fast. If it’s a saltwater lagoon the cattail wouldn’t be able to thrive in a saltwater environment. So hopefully this restoration can address public health concerns with the mosquitoes as well as improve the overall environment,” he said.

It was 2001 when CDFW started feasibility studies about restoring the lagoon to allow saltwater back into the system, but that process would prove to be anything but a simple fix. Because the weir is on private property, those property owners would have to be part of any solution to remove the device and introduce saltwater, and early suggested improvements weren’t well received. When CDFW discussions with landowners stalled, the cities of Oceanside and Carlsbad reached out to SANDAG for assistance in getting the weir-removal project re-energized. But being involved and making progress can be two very different things.

“It was going to be a big showdown between these two sides. One wanted saltwater, one wanted fresh water,” said Greer of SANDAG. “It was property owners versus stakeholders, and agencies versus everybody. Our board did something very smart, looking back. They stopped any kind of action on the project and said, ‘we’re going to give you guys one year, and you come back to us with a solution, or we’re going to make a decision at the SANDAG level.’ That did two things. First, it showed all the stakeholders that our board was serious and that if everyone couldn’t get on the same page, they were going to make a decision. The second, it gave the stakeholders time to reconvene and have access to our technical information to have meaningful conversations about the best thing to do. We sat with the homeowners and crafted a process moving forward. We met with wildlife agencies, and environmental groups and moved forward to allow the lagoon to get open to the ocean, while still meeting property owners needs out there.”

Though CDFW involvement in the negotiations met with resistance early on, Regional Manager Ed Pert played a major role in the discussions roughly 15 years later.

“He and I sat down with the owners and kind of crafted a process going forward,” said Greer. “We listened to their needs and to how we could help meet them. At the beginning, the homeowners felt like they weren't being listened to, they felt like the government was steamrolling them. I think Ed’s demeanor makes him really open to listening to people.”

Pert is quick to deflect the credit.

“It has been a long road in getting to the point where we can take concrete steps to restore the lagoon, and I very much appreciate the perseverance and efforts from those who made this happen,” said Pert. “Keith Greer and landowners who own the weir at the mouth of the lagoon in particular. Keith brought everyone to the table and kept us talking. Those folks deserve all the credit for finding a path forward,” he said.

The agreement reached on what’s called the Modified Saltwater Alternative would accomplish two things. First, it would reintroduce saltwater to the lagoon through a larger channel and the removal of the weir. Second, the lagoon will maintain a freshwater feel through a dredging operation that removes more than 900,000 cubic yards of sediment. Those deeper sections of the lagoon will remain filled with seawater at low tide. The agreement also calls for significant amounts of vegetation to be removed, which will help solve the mosquito issue.

“We're elated that the saltwater alternative has been approved, because it'll allow the lagoon to be reconnected with the ocean,” said Shapiro. “Returning the lagoon to a saltwater environment will greatly enhance the biological diversity, which will be very beneficial to bird populations. At the Audubon Society we're interested in bird habitat and currently, it's just not providing enough habitat diversity for birds. For example, there's an endangered species called the Ridgway’s rail which adapted to freshwater habitat, but it does really well with saltwater habitat. The big thing that's lacking right now are mudflats which will be created once there are tidal flows and that's important for shorebirds, like the Snowy Plover.”

Because this was never going to be a simple fix, huge hurdles remain before Buena Vista Lagoon is once again salty. While preliminary engineering is complete, state and federal permits must be obtained, and 5 million dollars is needed to make the project bid ready for construction. The final step is the highest of those hurdles; locating the 80 million dollars it will take for actual construction. Because SANDAG has recently restored another San Diego-area lagoon and is preparing to start work on another, Greer is confident the money will be found through state and federal sources.

“One year to be shovel-ready as we call it,” said Greer. “Within two years, I think we'll have a solid commitment for that 80 million dollars. Five years from now, we’ll probably be under construction.”

All those years of discussions and negotiations that eventually led to agreements and handshakes, on a project that would scare away many, is what makes Greer happy.

“Bringing all those groups together, that’s the fun part,” he said.


Media Contact:
Tim Daly, CDFW Communications, (916) 201-2958

CDFW Photos

Categories: Science Spotlight
  • January 28, 2021
Two hundred seventy gallon tank full of hydrogen peroxide for fish hatchery clean up

One of twenty-four 270 gallon totes of 10% Hydrogen Peroxide staged for raceway application. Hydrogen peroxide is used to kill the L. garvieae bacteria.

fish technician in personal protection equipment spraying hydrogen peroxide on the cement fish channels at the hatchery
Fish and Wildlife Technician at Mojave River Hatchery applying Hydrogen Peroxide to raceways. Over 224,000 square feet of raceway were treated between the three hatcheries.

fish technician in personal protection equipment spraying down the fish hatchery with hydrogen peroxide
Fish and Wildlife Technician at Mojave River Hatchery in his Personal Protective Equipment preparing to disinfect the raceways with Hydrogen peroxide.

fish technician hand scrubbing a fish settling tank
Hatchery worker cleaning debris from the hatchery settling pond to prepare for disinfection. Hatchery staff removed several yards of debris by hand to prevent tearing the rubber liner used to protect local ground water.

fish technician spraying hydrogen peroxide on the fish settling tank
Hatchery worker spraying hydrogen peroxide on the settling pond liner to kill L. garvieae bacteria.

Eight months after a bacterial outbreak in CDFW fish hatcheries led to the massive depletion of stocks, state fisheries biologists are still working hard on recovery efforts and a plan to stock California’s waters for anglers in 2021 and beyond.

Prior to the initial discovery at the Mojave River Hatchery in April 2020, the bacteria, Lactococcus garvieae, had not been found in California in aquaculture facilities or in the wild. Extensive testing of all CDFW hatcheries found the bacteria to be present in fish at the Fish Springs Hatchery and Black Rock Hatchery as well. Fish at all three hatcheries were immediately quarantined and ultimately 3.1 million trout were euthanized after treatment efforts were unsuccessful.

Over the following months, the three hatchery facilities have undergone intensive disinfection and a team of scientists has been working to test a vaccine developed to prevent infection from the bacteria. Meanwhile, fisheries managers at other state trout hatcheries are working on a joint effort to realign how the trout stocks statewide will be apportioned in order to continue to provide angling opportunities.

Most of the trout affected by the outbreak were destined for Eastern Sierra and Southern California waters. Seven state hatcheries not affected by the bacteria instituted a redistribution plan of healthy fish stocks making trout available to a subset of priority waters normally planted by the hatcheries that were quarantined.

Another priority has been to find or develop an effective vaccine, according to Jay Rowan, CDFW Statewide Hatchery Program Manager. Dr. Mark Adkison of CDFW’s Fish Health Laboratory is leading the state’s efforts in coordination with Dr. Esteban Soto of the UC Davis Aquatic Animal Health Lab in the UC Davis School of Veterinary Medicine. Although there are commercially produced vaccines available, scientists found that they most likely would not protect fish against the genetically distinct strain of L. garvieae bacteria affecting the fish in California’s hatcheries. Together, the scientists have been focused on making an “autogenous” vaccine, produced with the strain of L. garvieae bacteria that is unique to California. The vaccine is currently undergoing laboratory trials.

While the vaccine is being developed, hatchery managers have been hard at work disinfecting the affected facilities. After specialists from UC Davis ran experimental treatment scenarios to determine the most effective disinfectant options, CDFW was able to select and enact a comprehensive treatment plan. All surfaces and equipment were thoroughly cleaned and then disinfected with hydrogen peroxide at a concentration shown to remove biofilms and inactivate the bacteria. These measures were completed in December.

CDFW Fish Hatchery Manager Paco Cabral describes the effort as “lots of work.” Cabral was in charge of the massive and meticulous cleaning regimen to remove the bacteria from Mojave River Hatchery. Every surface that has come into contact with hatchery water requires disinfection -- including the hatchery building tanks, raceway holding ponds, settling ponds, pipes and all related fish rearing and planting equipment, and fixtures such as screens, nets and planting trucks. Even the staff’s waders and boots have to be disinfected.

To cleanse 6,000 feet of concrete raceways, staff utilized a 250-gallon high pressure spray washer to clean algae and dirt off each of the 10-foot by 1,000-foot structures. Once this is complete, backpack sprayers are used to apply a mixture of water and hydrogen peroxide to break down and kill the bacteria. Without these extensive measures, the bacterial will form a protective biofilm allowing it to survive even in the harsh dry conditions of the Mojave Desert in the summer and freezing cold conditions in Eastern Sierra in the winter.

Inside the hatchery buildings, all surfaces -- from incubation structures, tables and trays to faucets and hoses – must be disinfected. The cleaning process also includes all the hatchery plumbing, which is disinfected with the same hydrogen peroxide solution delivered via a gas-powered, high-pressure drain cleaner.

Over the summer, CDFW launched Phase 1 of the stocking plan by reallocating 40,000 catchable fish from central and northern California hatcheries to 16 waters in the Eastern Sierra and Southern California that would have normally been stocked by the infected hatcheries. Decisions about which waters would be stocked were not made lightly; fisheries managers carefully evaluated all options and selected locations based on angler accessibility and suitable water temperatures. Justin Kroeze, Fish Hatchery Manager at Moccasin Creek Hatchery, reports that during July, August and September, the staff from his hatchery were able to plant east side waters with 12,000 pounds of trout.

In Phase II of the stocking plan, which took place in October and November, CDFW reallocated and completed planting approximately 30,000 sub-catchable brown trout and 125,000 sub-catchable rainbow trout from American River Hatchery near Sacramento to Eastern Sierra waters. These fish are intended to be “put and grow,” available to anglers for the spring 2021 trout openers. They were reallocated from the June 2020 high elevation air plants that were cancelled due to staff safety concerns for COVID-19.

In December, Moccasin Creek Hatchery and San Joaquin Hatchery transferred approximately 125,000 rainbow trout to Fillmore Hatchery for stocking into Southern California waters during the December-through-March timeframe. These transferred fish join the approximately 500,000 rainbow trout already at Fillmore Hatchery that are getting close to reaching planting size. Moccasin Creek Hatchery plans to transfer an additional 40,000 rainbow trout to Fillmore in the coming weeks to assist in stocking efforts.

“It feels good to be able to help out the closed hatcheries and plant fish for the anglers in the Eastern Sierra and Southern California,” Kroeze said. “We’ve been in a similar situation here at Moccasin with no fish to plant, so we understand the situation they are in.”

Anthony Holland, Fish Hatchery Manager at Fillmore Hatchery, said that his staff are working to do everything possible to provide fishing opportunities for anglers in Southern California by planting out and holding incoming fish from the northern hatcheries. These plants are being posted on the CDFW trout planting schedule one to two weeks prior to the stocking date.

“We’re getting these fish out as fast as we can to provide angling opportunities to Southern California,” Holland said. “It’s been a while since these waters have been planted, so it’s great to see fish going in and people catching fish.”

In addition, Moccasin Creek Hatchery and San Joaquin Hatchery are holding approximately 400,000 sub-catchable trout for future transfer to the three depopulated hatcheries to help give them a jump start in their efforts to return to planting the waters in their areas in 2021. These trout were made available due to the decision last year to hold and grow extra trout at Moccasin Creek Hatchery once the hatchery came back online after major flood repairs were completed. Once the three affected hatcheries are back online, the number of waters planted will increase dramatically as an annual cycle of rearing is completed. It takes approximately 9 months to 18 months to rear a trout to one-half pound, which is the targeted size for catchable planting.

For additional information, please see link opens in new windowCDFW’s frequently asked questions about the L. garvieae outbreak (PDF). Please email questions to


Media Contact:

CDFW Photos

Categories: Science Spotlight
  • January 19, 2021

Luis Santana, fisheries biologist for the Yurok Tribe, holds up a Chinook salmon carcass found in one of the side channels being constructed along the Sacramento River near Anderson in Shasta County.

Scientist, Doug Killam standing on the rocky banks for the Sacramento River with trees and shrubs in background
Doug Killam, senior environmental scientist with CDFW’s Northern Region, stands along the first of three side channels that was excavated and connected to the main stem of the Sacramento River in 2020.

Sacramento River with willow and cottonwood cuttings placed for a cooling canopy for salmon with rocky banks and dense shrub
Willow and cottonwood cuttings have been placed throughout the side channels construction site. They will ultimately provide a cooling canopy for salmon and steelhead and relief from the areas’ scorching summer heat.

Trucks on the side of the Sacramento River moving earth to create side channels along a rocky bank
Creating three meandering side channels off the Sacramento River near Anderson has involved heavy construction and earth-moving equipment over the past 12 months.

Sacramento River side channel of slow cooling water for salmon with rocky banks and dense shrub
An oasis of slow-moving, meandering, cooling waters with deep pools and oxygenating riffles off the Sacramento River near Anderson will offer new spawning and rearing habitat for both salmon and steelhead.

An oasis of meandering waterways with deep pools, shallow gravel beds, protective log overhangs, oxygenating riffles and a cooling canopy of willows and cottonwood trees is being created for salmon and steelhead along the banks of the Sacramento River on CDFW-owned property near the city of Anderson in Shasta County.

Three new side channels off the Sacramento River have been carved from a dense, 40-acre riparian zone and floodplain that is being reconnected to the river adjacent to the Anderson River Park. The new habitat will serve as a protective nursery for juvenile salmon and steelhead off the main river while providing additional spawning habitat for adult fish.

“This was designed for rearing habitat,” explained Doug Killam, a senior environmental scientist with CDFW’s Northern Region, on a recent tour. “The moment we opened up the first channel and connected it to the river, adult salmon started showing up right away.”

The side channel project at Anderson is one of two currently under construction along the Sacramento River – the other taking place in downtown Redding. Both projects are being overseen by the U.S. Bureau of Reclamation as part of the Central Valley Project Improvement Act to mitigate impacts from lost habitat resulting from the construction of the Shasta Dam in 1945. Rocks and gravel being added to the side channels for fish habitat historically would have been delivered from upper reaches of the Sacramento River and all of the tributaries above Shasta Dam.

The Bureau of Reclamation contracted construction of the Anderson-area project out to the Yurok Tribe, whose reservation is situated along the lower 44 miles of the Klamath River. The tribe’s culture is rooted in salmon and fishing along the North Coast. Construction began a year ago and is nearly complete.

Few outside materials were brought in. Almost everything used to create ideal and idyllic fish habitat – stumps and snags, gravel and stones, willow and cottonwood cuttings – were acquired locally at the construction site, repurposed and recycled. The side channels themselves were dug out and designed based on historic waterways that used to exist.

“The Yurok Tribe has been fishing for time immemorial and being a fisherman myself, we know what salmon want,” said Luis Santana, fisheries biologist for the Yurok Tribe. “Everything we’re doing here is in the best interest of native fishes.”


Media Contact:
Peter Tira, CDFW Communications, (916) 215-3858

CDFW Photos

Categories: Science Spotlight
  • January 12, 2021
view of Salton Sea

Salton Sea, Riverside and Imperial Counties.

ditch in sand on the Salton Sea
Surface roughening at Salton Sea.

monitoring equipment on the beaches of the Salton Sea with mountains in background
Monitoring equipment.

Dust suppression signs on the beach of the Salton Sea
Dust suppression at Salton Sea.

two scientist looking in a creek for desert pupfish with rocks and bushes
Fishery biologists Sharon Keeney of CDFW (r) and Shauna Bishop of Barrett's Biological Surveys look for desert pupfish.

Stretching between Southern California’s Imperial and Coachella valleys, the Salton Sea is what one might call a landmark of untraditional beauty. At 33 miles long and 5 miles wide, it’s the state’s largest inland lake, serving a crucial role as a stopover for migratory birds using the Pacific Flyway.

But the Salton Sea lacks the conventional, inviting atmosphere of other lakes on the West Coast. Its waters are rapidly evaporating, leaving another few thousand acres of dry and dusty lakebed (playa) each year. That loss of water increases the lake’s already-high levels of salinity, and it occasionally emits a pungent rotten egg odor that permeates the air. And – of particular concern to scientists – the evaporation decreases habitat for the wildlife that has historically thrived in and around this important ecosystem.

“Since its formation, the Salton Sea has been fed by irrigation runoff in the Imperial and Coachella valleys and inflow from rivers,” explained CDFW’s Salton Sea Program Manager Gail Sevrens. “But water transfers and related agreements and measures have contributed to a reduced volume of runoff, and as the water evaporates, the Sea has lowered in elevation. This has led to a shrinking, saltier Sea, and those increased areas of exposed dry lakebed can emit dust, which is of concern to local communities.”

Sevrens oversees CDFW’s participation in the Salton Sea Management Program (SSMP), which seeks to address those concerns, both for the benefit of fish and wildlife and the humans that live in the valley. The SSMP is an effort between CDFW and the California Department of Water Resources, under the direction of the California Natural Resources Agency. The partners seek to implement projects that will slow the damage and aid in recovery, primarily through the construction of approximately 30,000 acres of habitat and dust suppression projects around the Sea.

The program has several priorities:

  • Making significant, visible progress in getting restoration and dust suppression projects accomplished as part of its 10-Year Plan;
  • Creating a long-term plan;
  • Building the team; and
  • Strengthening local partnerships.

Many Californians are unfamiliar with how the current Salton Sea came to existence – it’s not an exaggeration to call this an “accidental lake.” Though large seas have formed and dried here throughout history due to natural flooding from the Colorado River, the Salton Sea in its current iteration was born in 1905 when the Colorado River breached an irrigation canal being constructed in the Imperial Valley. The escaping water slowly filled a dry lakebed nearly 300 feet below sea level. At first, developers imagined the Sea as a popular lakeside resort. But it was not to last, as without a continued, reliable source of water supply, the lake’s waters could only evaporate, reducing conditions for wildlife and nearby residents. In fact, due to agricultural runoff and evaporation, the water in the Salton Sea is approximately twice as salty as ocean water.

This fall, work began on the nearly 4,000-acre Species Conservation Habitat (SCH) project. That work will create a series of ponds at the southern end of the Sea that will include nesting and roosting islands and areas of varying water depths to serve as fish and bird habitat. At its healthiest, the Salton Sea was host to a half dozen species of fish, while 400 species of birds visited the lake while traversing the Pacific Flyway.

The SSMP projects provide dust suppression benefits. For example, temporary dust suppression measures have been taken on the south side of the Sea at the SCH site, where, through a process called surface roughening, approximately 700 acres of land were manipulated to create ridges and furrows that are perpendicular to the prevailing wind direction. Additional dust suppression and habitat restoration projects are in development for areas of exposed dry lakebed around the Salton Sea.

According to CDFW Environmental Scientist Samantha Przeklasa, the seemingly simple approach of rearranging the ground can make an enormous difference. “When the wind comes across the surface-roughening furrows, they slow the wind and catch particulate matter in the air. That matter gets caught in the little furrows, in the low spots.

(Watch this link opens in new windowvideo tour of the Salton Sea with Environmental Scientist Samantha Przeklasa)

Though habitat work is just beginning, scientists are seeing the benefits for one species already. Przeklasa praises fellow CDFW Environmental Scientist Sharon Keeney for her work finding, relocating and ultimately saving desert pupfish. The only native fish species at the Salton Sea, the tiny pupfish are found in shoreline pools, agricultural drains and natural creeks. Though pupfish can survive low levels of dissolved oxygen, high salinity and high water temperatures, they won’t survive in ponds and ditches that go dry. That’s where Keeney’s work has truly made a difference.

“There are many irrigation drains across the entire Salton Sea, on the north and south. Sharon spends a lot of her time monitoring those drains to see where the pupfish are thriving, and then rescues them from small drains that may be about to completely dry up,” said Przeklasa. “From a small pond, we can get hundreds, if not thousands, of fish out of it.” The fish are relocated to nearby ponds that are fed by natural desert springs, or managed ponds. Desert pupfish have also been relocated to ponds at a local high school, UC Riverside’s Palm Desert campus, and the Living Desert Zoo and Gardens in Palm Desert. The latter has even named one of its newest desert pupfish refuge ponds after Keeney.

Ultimately it will be engineering and habitat construction that helps the pupfish and other species survive. The work being done brings joy to program manager Sevrens, who was first attracted to the unusual beauty of the Salton Sea through documentaries. Her affection for the lake grew even further while bird-watching and occasionally kayaking there.

“A lot needs to go on behind the scenes before you can actually do a project, and we are moving forward on multiple project tracks at a time,” she said. “It’s exciting to see the pieces coming together.”


Media Contact:
Tim Daly, CDFW Communications, (916) 201-2958

CDFW Photos

Categories: Science Spotlight