Science Spotlight

  • July 20, 2020

Biologist, Paul Divine releasing a bass fish back in to the lake off the side of a boat
Paul Divine, Lassen County district fisheries biologist for CDFW, releases Largemouth Bass fry into Mountain Meadows Reservoir in 2018 as part of the effort to rebuild a trophy bass fishery that existed before the reservoir went dry in 2015.

scientist hold a bass fish while on a boat on a lake with tall trees in background and blue sky above
Former CDFW Scientific Aid Joshua Faughn holds up a chunky Largemouth Bass that turned up in one of CDFW’s electrofishing surveys of Mountain Meadows Reservoir. CDFW has electrofished the reservoir five times since water returned following the 2015 drought.

biologist holding a small green and yellow pumpkinseed perch fish in his hands on a boat on a lake
Pumpkinseed Sunfish have recolonized Mountain Meadows Reservoir on their own. Biologists believe they survived the drought and the reservoir going completely dry by holding out in one of the reservoir’s creek arms.

Monty Currier’s heart sank when an excited angler told him recently of catching trophy-sized crappie at Mountain Meadows Reservoir in Lassen County.

For the past five years, Currier, a California Department of Fish and Wildlife (CDFW) environmental scientist assigned to reservoir fisheries in the north state, has been working to rebuild the fishery at Mountain Meadows Reservoir after the Pacific Gas and Electric (PG&E) impoundment went dry in 2015 from the combined effects of maintenance work and the drought. Crappie were not part of the restoration plan.

Currier’s spirits lifted when the angler pulled out his phone. The photos he proudly showed off were not of crappie – but rather of good-sized Sacramento Perch, California’s only native sunfish and the result of CDFW transplants from Biscar Reservoir in Lassen County, Lake Almanor in Plumas County and Clear Lake Reservoir in Modoc County.

Anecdotal progress reports such as these have had to sustain Currier of late along with his CDFW colleagues Paul Divine, a district fisheries biologist for Lassen County, and Amber Mouser, who oversees fisheries issues in Plumas County and has worked closely on the Mountain Meadows Reservoir restoration. Plans to formally survey and electrofish Mountain Meadows Reservoir this past spring and next fall have been postponed as a result of COVID-19-related social distancing mandates preventing the work, which typically requires three people working in close proximity aboard an electrofishing boat.

The unfortunate 2015 fish kill at Mountain Meadows Reservoir presented Currier with something of a dream opportunity.

“It’s pretty special because you don’t often get the chance to start from scratch and build up a fishery,” he said. “It takes a lot of diligence, multiple agencies and groups working together to make things happen. There are a lot of moving parts.”

In addition to Sacramento Perch, stocking largemouth bass and seasonal rainbow trout have also been part of the restoration efforts. But before any fish were introduced, CDFW added 600 fish habitat structures in 2016 consisting of brush piles and recycled Christmas trees to jump-start the habitat.

Although Mountain Meadows Reservoir today brims with 5,800 acres surface feet of water, the lake is shallow – at no more than 15 or 16 feet at its deepest point – and heavily vegetated. It offers good habitat to support a self-sustaining largemouth bass fishery and a put-and-take recreational trout fishery in cold weather months. Prior to going dry in 2015, the reservoir offered a trophy largemouth bass fishery and hosted several tournaments and other fishing contests each year.

Rebuilding the popular largemouth bass fishery began in earnest in 2017 with captured bass transplanted from Antelope Lake in Plumas County. In 2018, 2,000 fingerling largemouth bass were purchased from a private hatchery and stocked through the combined efforts of PG&E, the Mountain Meadows Conservancy, local anglers and community sponsors. Last year, largemouth bass were transplanted from Biscar Reservoir. Currier works with CDFW fish pathologists to ensure that the fish are disease-free and safe to translocate.

A spring electrofishing survey would have provided insight on how many bass were now spawning in Mountain Meadows Reservoir. A fall survey would reveal how successful the spring spawning had been.

The last time CDFW had a chance to monitor the recovery was in August of 2019 when two electrofishing boats sampled the western portion of the reservoir. The results were encouraging: 718 fish were captured, the highest catch overall compared to the four previous electrofishing surveys since the reservoir was rewatered.

Fifty-six largemouth bass were captured last August, many being juveniles indicating natural spawning was occurring. Twenty-four Sacramento perch turned up – compared to just three of the fish captured in two previous surveys combined earlier in the year, though well below the 80 Sacramento perch captured in 2018.

The most plentiful species of sport fish in the August 2019 survey was the pumpkinseed sunfish at 417. The pumpkinseed sunfish fishery is very popular at the reservoir, said Currier, and appears to be recovering without the aid of stocking or transplants from CDFW. Currier said the fish likely repopulated the reservoir from one of the creeks that feeds into it.

Currier and CDFW biologists are particularly interested to see whether the pumpkinseed sunfish and Sacramento perch can co-exist over time. Native Sacramento perch, which evolved in the Sacramento-San Joaquin Delta prior to the introduction of non-native sunfish and other predatory species from the Midwest and East Coast, have trouble competing for food and habitat with more aggressive, non-native sunfish such as the pumpkinseed and crappie.

Sacramento perch are an otherwise hardy and adaptable sport fish appreciated by anglers for their fine table fare. CDFW fisheries biologists are constantly on the lookout for suitable waters to expand their range, expose them to more anglers and ensure the species genetic diversity and survival.

Overall, pumpkinseed sunfish accounted for 64 percent of the electrofishing catch in Mountain Meadows Reservoir from 2017 to 2019 compared to Sacramento perch that represented just 7.6 percent of the sampled fish. Three 2019 electrofishing surveys resulted in lower Sacramento perch numbers than in 2018, but CDFW scientists such as Currier note that Sacramento perch can be difficult to electrofish and net due to their dark coloration that makes them difficult to see and their tendency to hold in heavy cover. Other factors such as different water temperatures at the time of the surveys could explain some of the drop-off in Sacramento perch numbers from 2018.

One hundred forty-three Sacramento perch were translocated to Mountain Meadows Reservoir from Biscar Reservoir as recently as June 2019 in an attempt to boost the breeding stock. That anglers are now catching Sacramento perch worth bragging about – even if they are sometimes mistaken as black crappie – is something Currier and his colleagues can take pride in for now.


CDFW Photos. Top Photo: CDFW Environmental Scientist Monty Currier proudly shows off a Mountain Meadows Sacramento Perch, which CDFW introduced into the reservoir to provide an exciting sport fishery for local anglers.

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

Categories: Science Spotlight
  • July 9, 2020

Hallprint, spaghetti-style fish tags provide visual identification for Feather River Fish Hatchery staff that returning salmon are spring-run Chinooks that can be used for spawning and perpetuating the run of fish.

Spring run Chinook salmon receives a fish tag in the Feather River Fish Hatchery
An early arrival to the Feather River Fish Hatchery receives a Hallprint, spaghetti style fish tag identifying it as a spring-run Chinook salmon before it is returned to the Feather River.

Two Feather River Fish Hatchery employees sort and prepare spring run Chinook salmon for tagging
Feather River Fish Hatchery staff prepare spring-run Chinook salmon for tagging before these early arrivals are returned to the Feather River.

group of spring run Chinook salmon swim inside a holding tank within CDFW's Feather River Fish Hatchery in Butte County
Spring-run Chinook salmon inside the Feather River Fish Hatchery.

The California Department of Fish and Wildlife’s Feather River Fish Hatchery in Butte County recently completed the tagging of 2,746 spring-run Chinook salmon in May and June.

The fish were early arrivals to the hatchery. After being outfitted with two external Hallprint, spaghetti-style fish tags on either side of their dorsal fin – two tags in case one comes out and is lost – the fish were returned to the Feather River. Unlike Passive Integrated Transponder (PIT) tags injected into many Chinook salmon smolts in order to monitor their movements, returns and hatcheries of origin, the external Hallprint tags are intended to provide visual identification to hatchery staff of returning spring-run Chinook salmon.

In September and October, the hatchery will spawn spring-run Chinook salmon, selecting among only those returning, externally tagged fish as broodstock in order to preserve the integrity of the spring-run fish and not mix genes with returning fall-run Chinook salmon. The ladder to the Feather River Fish Hatchery was closed July 1 to ensure only the early arriving spring-run Chinook salmon were tagged.

This process helps the hatchery achieve its goal of selecting and spawning salmon that represent the entire timeline of returning fish while keeping spring-run and fall-run salmon separated.

Feather River spring-run Chinook salmon are classified as threatened under both the state and federal endangered species acts. Tagging and spawning efforts help mitigate their decline. The goal is to ensure these native California fish can be enjoyed by generations to come.

CDFW Photos

Categories: Science Spotlight
  • July 6, 2020

Isaac Chellman, high mountain lakes environmental scientist for CDFW’s North Central Region, nets non-native trout from a lake to restore native frog habitat.

Sierra Nevada yellow-legged frog sits among the reeds in its high mountain lake environments with trees and blue sky in the background
The Sierra Nevada yellow-legged frog is listed as a threatened species under both the California and federal endangered species acts.

close up look of a Sierra Nevada yellow legged frog, which blends in well into its native, high mountain lake habitat. The frog is on a dark rock partially in a lake
Non-native trout introduced into high mountain lakes prey upon native Sierra Nevada yellow-legged frog tadpoles and young frogs. Removing these trout from select lakes is an important step in recovering native frog populations.

In the Tahoe National Forest, California Department of Fish and Wildlife scientists are working to balance native species restoration with recreational fishing.

This summer, for the first time in the Tahoe National Forest, CDFW will begin work to restore Sierra Nevada yellow-legged frog (Rana sierrae) habitat by removing introduced trout from four alpine lakes and four small ponds within the Five Lakes Basin area. The Sierra Nevada yellow-legged frog is listed as threatened under California’s Endangered Species Act and endangered under the federal Endangered Species Act. 

The Five Lakes Basin is located in Nevada County, south of French Lake and Faucherie Lake within the Grouse Ridge non-motorized area of the Tahoe National Forest. The area is a popular destination for backcountry recreation. The small lakes and ponds targeted for fish removal include Glacier Lake and are typically accessed from the Grouse Ridge Campground and Faucherie Lake.

“These types of projects highlight CDFW’s dual mission to both provide recreational opportunities and recover native species,” said Sarah Mussulman, Sierra fisheries supervisor for CDFW’s North Central Region. “In this case, we want to ensure anglers have a chance to catch a fish at a beautiful lake while simultaneously ensuring this iconic native frog remains on the landscape for generations to come. Because the fish are a major driver of frog declines, we’ve chosen one area near Grouse Ridge to recover frogs and a nearby area to plant fish.”

To remove the fish, which consist of non-native brook, rainbow and hybridized golden-rainbow trout, CDFW will use mechanical methods including monofilament gill nets and backpack electrofishing units. This project is funded by the U.S. Fish and Wildlife Service through its endangered species recovery grant program and will be conducted in collaboration with the Tahoe National Forest. Work is scheduled to begin by mid-summer and will continue through the fall 2022.

The Sierra Nevada yellow-legged frog was once one of the most abundant species in the Sierra and a critical part of the natural food chain. Non-native trout, which were introduced into historically fishless lakes and ponds throughout the range for many decades, consume young frogs and tadpoles. This predation has been a major contributor to the decline of these native amphibians. The restoration project will provide additional fishless habitat, which is needed for the long-term survival and eventual recovery of this species.

At the same time, CDFW is committed to promoting and maintaining the unique recreational fishing opportunities nearby. CDFW will continue to stock trout into many lakes in the Grouse Ridge area, including Carr, Culbertson, Feeley, Long, Milk, Upper and Lower Lindsey, Big and Little Island, and Lower and Upper Rock lakes. These locations provide fishing opportunities at beautiful, high elevation lakes within a few miles of the Five Lakes Basin.


CDFW Photos

Categories: Science Spotlight
  • July 3, 2020

CDFW is a department with about 1,200 employees in scientific classifications, spread from Yreka in the north to Blythe in the southeast. Their expertise spans a broad spectrum of subjects – wildlife management, fisheries management, marine issues, habitat conservation and restoration, veterinary science, pathology, genetics, invasive species and so much more.

Coordinating the efforts of a department with such a wide range of specialties is no small task. But back in 2006, CDFW released its Strategic Initiative, which laid the groundwork to do just that. The document outlined the strategies and actions that the department should take in order to increase its effectiveness across the board. One specific goal was to expand the department’s scientific capacity – to establish best standards and practices, to improve access to scientific literature, and heighten visibility and awareness of scientific efforts.

CDFW Science Institute was launched in May 2012 as the means to accomplish those goals. Initially, it was led by a team of dedicated scientist that put the Science Institute on the map with a public website, a scientific lecture series, science symposium, policy and guidance documents on scientific practice, and ultimately hiring a Science Institute Lead in 2018. Since then, the Institute has grown to include a committed scientific staff of five employees who work to support CDFW’s scientists and scientific efforts.

CDFW’s Science Advisor and Science Institute Lead, Christina Sloop, points out that climate change and biodiversity conservation are two issues that affect all facets of the department -- yet specific resources on these topics are not readily available to many field staff. The Science Institute employs staff who are specifically trained to advise on these topics, and can provide a statewide, long-term perspective.

“We are ready to provide guidance and help connect the dots when climate change or biodiversity conservation principles could be incorporated into a study or a project,” Sloop explains. “We play a departmentwide facilitation role, so CDFW’s scientists and scientific programs can better respond to these challenges and be as efficient as possible as they work to support our important mission.”

CDFW recently published the link opens in new windowScience Institute Progress Report 2018-2019 (PDF), which highlights the tools developed so far. The 2020-2025 Science Institute Strategic Action Plan will be released this summer. This document reflects input from the CDFW science community and lays out goals and strategies to guide the Science Institute’s priority actions in the next five years. Each year, the plan will be reassessed, reevaluated and updated as necessary, in order to keep one step ahead of current challenges. “Our goal is to be proactive and anticipatory rather than reactionary,” Sloop said. “We’ll always be on the lookout for new ways to build capacity, promote transparency and foster scientific excellence.”


Media Contact:
Kirsten Macintyre, CDFW Communications, (916) 804-1714

Categories: Science Spotlight
CDFW Science Institute logo


Receive Science Institute news by email.