Science Spotlight

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  • April 12, 2019

Laminated sign with fish that reads attention anglers attached to old wooden sign on metal post in grassy area with lake and mountains in background
Lake-side signage lets anglers know Kirman has recently been stocked with wild brook trout and asks for help from anglers in competing a brief survey about their fishing experience.

Seven people in waders and machine backpacks holding nets and yellow poles in stream.
CDFW fisheries biologists electrofish Silver Creek in Mono County to remove non-native brook trout to reduce competition with native cutthroats.

Hand palm facing up with several water bugs in palm
The tremendous amount of aquatic life within Kirman Lake provides a nearly unlimited food supply for transplanted brook trout from Silver Creek and transplanted Lahontan cutthroat trout from Heenan Lake. Kirman itself has no spawning habitat and is dependent on trout plants from CDFW to maintain the trophy trout fishery.

Small speckled fish laid on top of measuring tape and wooden board.
Before release into their new home in Kirman Lake this fall, brook trout were measured and their adipose fins clipped. CDFW scientists plan to track their growth rates with the help of voluntary angler surveys.

It’s a question that has been asked by more than a few eastern Sierra trout anglers: What happened to the fishing at Kirman Lake?

Kirman, a small backcountry lake north of Bridgeport in Mono County, has long been heralded as one of the very few places in the state where anglers could catch trophy brook trout.

While many high-elevation waters hold overpopulations of stunted brook trout measured in inches, the brook trout in Kirman were measured in pounds. Fish in the 2- to 4-pound class were common with numerous reports of brookies exceeding 5 pounds.

The lake requires a moderate, 3-mile hike to reach – just enough distance and difficulty to discourage casual anglers and help minimize some of the fishing pressure, particularly with so many great trout fishing options nearby. The lake is a special-regulations water with limited harvest. It is open to fishing during the state’s traditional trout season from the last Saturday in April to Nov. 15. Only artificial lures with barbless hooks may be used. Only two trout can be kept – with a minimum size limit of 16 inches.

Kirman was a destination known well beyond the confines of Mono County.

Fly fishing author and instructor Denny Rickards included Kirman in his book “Fly Fishing the West’s Best Trophy Lakes.”

Rickards writes, “Those who have made the trek and landed one of these beautiful trout know what a delicate lake it is. Part of the promise here is more than just big brook trout – the lake also harbors big cutthroat. However, the cuts aren’t the primary focus of those who fish here. It’s those big, beautiful brookies that bring fishermen up the trail.”

Author Bill Sunderland likewise highlighted Kirman in his book “Fly Fishing California Stillwaters.” He writes, “The fish here, both brook trout and Lahontan cutthroats from Heenan Lake, grow exceptionally fast. A four-year-old brookie can be twenty inches long and weigh four pounds. Many of them are football-shaped, the result of their rapid growth.”

In recent years, however, the brook trout seemingly disappeared with anglers reporting fewer catches with no brookies in the mix. Fishing reports from Kirman dried up as well at local tackle shops with fewer anglers apparently making the trek.

What happened to Kirman Lake and its trophy brook trout is no mystery to CDFW fisheries biologists, who are committed to restoring the lake to its former glory.

“There’s no spawning habitat,” explained Jeff Weaver, a senior environmental scientist with CDFW who oversees the department’s Heritage and Wild Trout Program. “All the fish in Kirman Lake have been stocked to provide the recreational fishery.”

Brook trout were planted annually by CDFW until 2015 when hatchery problems prevented the raising and delivering of the fish.

What Kirman lacks in spawning habitat it makes up for in food abundance. Unlike many high-mountain lakes where trout eke out an existence in near-sterile conditions, Kirman is the equivalent of a 24-hour, all-you-can-eat buffet. The lake is loaded with all manner of aquatic invertebrates -- water boatman, dragonflies, mayflies and midges – along with high-protein leeches and shrimp-like scuds. The heavy population of scuds accounts for the tremendous growth rate and size of Kirman brook trout.

When Russell Black, CDFW’s new fisheries supervisor for the Inland Deserts Region, learned about the lack of hatchery plants and the poor state of the once-great fishery, he came up with a simple yet creative solution.

This past fall, work was underway at nearby Silver Creek to prepare the water for the eventual restoration of native Lahontan cutthroat trout. CDFW biologists electrofished Silver Creek to remove the non-native brook trout there to minimize competition with the native cutthroats.

Black’s idea: Take those brook trout and transport them to Kirman.

More than 1,300 Silver Creek brook trout in a variety of sizes were relocated to Kirman. Prior to release, the fish were measured and their adipose fins clipped. CDFW biologists encourage anglers at Kirman this upcoming trout season to record their catch and fishing experiences at angler survey boxes lakeside so they can track the transplanted Silver Creek brook trout.

Given the exceptional growth rate at Kirman, CDFW biologists expect anglers to get into some quality fish by the fall.

Even as CDFW shifts its statewide trout hatchery focus to raising and stocking native trout as opposed to non-native brown trout, brook trout or even domesticated strains of hatchery rainbow trout, biologists see a future for trophy brook trout in Kirman and are exploring options to resume annual hatchery stocking.

“Kirman Lake is one of those celebrated fisheries where we weigh management in favor of continuing that recreational fishery,” said CDFW’s Weaver, who himself has fished Kirman a dozen or so times over the past 20 years. “Kirman Lake is managed as a trophy trout fishery and we intend to continue to manage it as a trophy trout fishery. We’ve just been on pause as a result of the lack of stocking.”

The pause may be over, though, as CDFW intends to maintain the supplemental stocking from Silver Creek until regular hatchery plants can resume.

CDFW Photos. Top Photo: This small brook trout was one of many relocated this fall from Silver Creek to Kirman Lake, where it could potentially grow into a trophy-sized fish awaiting anglers this trout season.

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

Categories: Wildlife Research
  • April 2, 2019

The latest issue of California Fish and Game, Vol. 105, Issue 1 (PDF), focuses on marine species, bringing new insights and understanding of several fish species found off the California coast.

In A very long term tag recovery of a California scorpionfish (Scorpaena guttata) (PDF), Roberts and Hanan report the remarkable recovery of a tagged scorpionfish that had been at liberty far longer than any previously recaptured scorpionfish. The recovery was made during a four-year mark-recapture study on nearshore groundfish off southern and central California. More than 32,000 fish were recaptured, with an average of 408.8 days at liberty. The study results indicate that scorpionfish demonstrate strong site fidelity, given that a majority of the fish were recaptured within 5k of their original tagging site. The scorpionfish that is the subject of the article was tagged in 2004. It had been at liberty for nearly 14 years (5,048 days). After removing the tag, the fisherman who captured the fish reported that he released it “unharmed and looking very healthy.”

Another paper reports on a method for estimating the age of roosterfish using dorsal fin spines (PDF). According to authors Chavez-Arellano et. al, the roosterfish is considered a prized species by the sport fishing community and provides a significant economic benefit to the Mexican tourism industry. However, little is known about its biology, ecology, and movement patterns. The authors embarked upon a study to assess which sections of roosterfish dorsal fin spines have the most legible indicators of growth for use in future aging studies. Their work provides the initial basis from which future aging studies can be conducted.

Finally,Primary and secondary nursery areas for leopard and brown smoothhound sharks in San Francisco Bay, California (PDF), summarizes a 31-year study to determine primary and secondary nursery habitats for leopard and brown smoothhound sharks within South San Francisco Bay, adding new knowledge to the biology of both species.

As it has for the past 105 years, California Fish and Game continues to publish high-quality, peer-reviewed science that contributes to the understanding and conservation of California’s wildlife. We look forward to witnessing the contributions of the next installment.

CDFW Photo.
Media Contact:
Lorna Bernard, CDFW Communications, (916) 322-8911  

Categories: California Fish and Game Journal
  • March 25, 2019

Partial map of the State of California with area marked in black outline and covered in small black dots.
CDFW scientists conducted a groundbreaking survey of lizards across the entire Mojave Desert. CDFW graphic.

One might say that a groundbreaking new study conducted by two CDFW scientists and their research partners provides a leap forward in lizard research.

Dr. Brett Furnas, a senior environmental scientist with CDFW’s Wildlife Investigations Lab, is the lead author on a paper entitled link opens in new tab or windowHierarchical distance sampling to estimate population sizes of common lizards across a desert ecoregion. The co-authors on this paper are Scott Newton and Griffin Capehart, both formerly contractors for the Wildlife Branch at CDFW, and Dr. Cameron Barrows with the Center for Conservation Biology at the University of California, Riverside.

According to Furnas, monitoring programs that survey many wildlife species at the same time across large geographic regions are important for informing conservation decisions, but reptiles are often missing from these efforts because they are difficult to survey. Therefore, the researchers applied a new distance-sampling approach to more accurately count lizards across the entire Mojave Desert within California (25,803 square miles in total).

“As far as we know, this is the first time a lizard population has been accurately enumerated over such a large area of desert,” said Furnas.

Visual surveys of lizards were conducted in 2016 along quarter-mile long transects at 229 widely dispersed sites throughout the desert. The surveys were repeated several times during the same month, which allowed CDFW scientists to correct for lizards that were missed during any one visit due to hot weather and other factors. The researchers validated their results by comparing them against a different set of surveys conducted by Barrows over a much smaller area at Joshua Tree National Park.

After using advanced statistical models to extrapolate survey results across the entire desert, CDFW estimated 82 million lizards for the three most common species of lizards across an area amounting to 16 percent of the total land area of the state. The population numbers reflect an average of 3,170 lizards per square mile.

“Having a good measure of population size for any species is important because it allows us to make more effective conservation decisions when we know how abundant a species is, what habitats is uses, and whether it is increasing or declining in numbers,” Furnas said. “These are often the first questions decision-makers want answers to.”

This is especially important in the deserts of California and the Southwestern United States, which are already experiencing severe increases in temperature and reductions in rainfall due to climate change. There is concern that these increases in temperature may already be exceeding the physiological limits of some lizard species, thereby increasing their risk of extinction. 

“Lizards and other reptiles are particularly sensitive to temperature, in part because they are ‘ectothermic,’” explained Furnas. “Unlike mammals, reptiles cannot use their metabolism to regulate body temperature; instead they may need to take shelter on very hot days, which may limit the time they can spend foraging for food.”

In addition to demonstrating the value of a new method for monitoring reptiles, the study was able to map the distribution of lizards throughout the Mojave Desert and show how population levels and the behavior of lizards vary with differences in vegetation cover, human land use, and temperature. Of the three species studied, Western Whiptail (Aspidoscelis tigris) and Common-side Blotched Lizard (Uta stansburiana) were more abundant in cooler places found at higher elevations or where there was greater vegetation cover. On the other hand, Zebra-tailed Lizard (Callisaurus draconoides) was more tolerant of high temperatures, but was the most sensitive to human development and disturbance.
CDFW Photo and Graphic. Top Photo: This common side-blotched lizard (Uta stansburiana) was surveyed at Joshua Tree National Park. CDFW Photo by Cameron Barrow.

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Media Contacts:
Kyle Orr, CDFW Communications, (916) 322-8958
Brett Furnas, CDFW Wildlife Investigations Laboratory, (530) 227-3998  

Categories: Wildlife Research
  • March 20, 2019

Side of boat with two men wearing white hard hats leaning over the railing reaching for large black and green machine held up by a crane.
The ROV Beagle (CDFW photo)

Orange fish with very few white dots in dorsal region underwater next to large pinkish red sea plant
Starry Rockfish from the Channel Islands (CDFW photo)

Red and orange fish with spiny dorsal fin underwater. Red fish in background.
Yelloweye and Vermilion rockfishes from the North Coast (CDFW photo)

Orange fish with white stripes across head and down body underwater.
Canary Rockfish from the North Coast (CDFW photo)

Gray speckled fish underwater on top of rock covered in round white anemone
Lingcod, white-plumed anemones, female kelp greenling (CDFW photo)

Orange fish with thick white bands and spiny dorsal fin underwater over large rock covered in salmon pink creature with narrow, long spiraling limbs.
Quillback Rockfish and Basket Stars from the North Coast (CDFW photo)

Orange-pink creature shaped like a ball underwater with hundreds of long hair-thin extensions extended toward rock.
Benthic siphophores use threads to walk and anchor to the seafloor (CDFW photo)

Black and green machine with two yellow tanks on top above water, suspended by chain.
ROV Beagle (CDFW photo by Michael Prall)

Marine scientists from the California Department of Fish and Wildlife (CDFW) and Marine Applied Research and Exploration (MARE) recently completed an unprecedented three-year survey of deep-water habitats off the California coast using a remotely operated vehicle (ROV). Beginning in 2014, MARE’s ROV Beagle was deployed throughout the state to survey and record the species and types of habitats associated with marine protected areas (MPAs) and nearby, comparable rocky habitats.

Surveys were video-based and provided a first look at the many recently established MPAs throughout the state and generated much needed data on abundance and distribution of fish species harvested from rocky habitats.

According to Marine Environmental Scientist Mike Prall, “Many of the areas visited by the ROV Beagle during the surveys had probably never been directly observed by human eyes before our surveys. And all data gathered from video and still imagery collected during the expeditions have provided much needed information about California’s vast deep-water habitats.”

This statewide survey was funded by a $1.9 million research grant awarded to CDFW in 2013 to survey underwater habitats from Mexico to the Oregon border using state-of-the-art underwater technology operated by MARE. In all, five deployments visited over 130 locations and collected hundreds of hours of video in standard and high definition formats, as well as over 50,000 digital still photographs.

Working through MARE’s video processing laboratory in Eureka, trained technicians methodically characterized habitat and identified hundreds of species of fish and invertebrates from high definition video and still photography. Detailed information was also collected from the ROV’s path across the seafloor, which was then used to accurately identify the location of each observation. CDFW scientists used that data for future analysis of abundance, size estimates and patterns of distribution for important species, among other applications.

Preliminary examination of observations from the first ROV deployments have already uncovered interesting findings about species and habitats. In Southern California, small reef patches surrounded by soft sediments showed a high abundance of rockfish in many locations. These habitats are sparsely scattered throughout Southern California’s nearshore waters and may be important to overall fish abundance in areas lacking prominent rocky reefs.

Not surprisingly, the northern California surveys uncovered different findings from those in southern California. Rocky reefs in northern California had patchy distributions of fish, with some areas surprisingly devoid of common species. Strong ocean currents, large waves, and increased sedimentation from rivers created complex dynamics on the north coast and may have influenced the patchy distribution. One striking observation throughout all areas visited statewide was the high abundance of the predatory lingcod.

“Participating in this survey has been a high point of my career at CDFW,” Prall said. “As we continue to work with the massive amount of data gathered, I am excited to see what new results emerge and to see how this work will inform our understanding of California’s amazing underwater resources.”

CDFW scientists and MARE have been collaborating and have explored underwater habitats together throughout California waters since 2003 and have developed highly refined ROV survey methods and processing techniques. Since completion of this endeavor in 2016, this project has provided the most comprehensive and most thorough visual survey of California’s deep water rocky habitats ever attempted.

Information gathered from the data will provide insights into how species may be benefiting from protections afforded by MPAs and give resource managers greater knowledge of managed marine species. CDFW and MARE are currently partnering to survey warty sea cucumber populations in and around Anacapa Island State Marine Reserve. Two deployments funded by the Resources Legacy Fund were completed in 2018. Thanks to this work, scientists now better understand the biology of this important harvested invertebrate species, and in addition, the role of MPAs in the sustainability of the fishery.

Photos taken from the ROV Beagle during the project surveys can be seen on link opens in new windowCDFW's Flickr site. For more information about marine protected area monitoring efforts, visit the CDFW website.

Top photo: The ROV Beagle (CDFW photo by Michael Prall)


Media contact:
Carrie Wilson, CDFW Communications, (831) 649-7191

Categories: Wildlife Research
  • March 12, 2019

Monarch butterfly with wings closed hanging off of purple spikey flower.
USFWS Photo by Brett Billings

Map of North America titled Monarch Migration highlighting the United States with orange and yellow arrows, a legend, and a butterfly
Figure 1 from The Xerces Society’s link opens in new windowConservation Status and Ecology of the Monarch Butterfly in the United States (PDF)

For residents of many coastal California towns, the colorful Monarch butterfly (Danaus plexippus plexippus) migration has been a welcome wintertime sight for generations. The beautiful and distinctive orange-and-black patterned insects have historically congregated at more than 400 known sites in the Golden State. Visitors flock to see them, and some towns – such as Pacific Grove, Big Sur and Pismo Beach -- have built entire economies around the return of the butterflies.

The life history of the Monarch butterfly is fascinating in that none of the individuals that arrive each winter have ever been there before. Each year, the Monarchs that were born throughout western North America flutter to the warmer climates of the California coast, typically in mid-October, but sometimes as early as September. They form dense masses high in the trees, where they remain relatively dormant (scientifically known as reproductive diapause) until February or March, when flowers with nectar and the milkweed needed by their young (caterpillars) become plentiful. At that time, they mate and begin to disperse and lay their eggs. The offspring then grow into butterflies, which in turn mate and lay eggs while continuing to disperse over a two to five week period. The process continues until fall when temperatures drop, triggering migration of the current generation of butterflies back to the west coast.

As recently as the 1990s, an estimated 1 million butterflies would overwinter along the California coast each year. But over the past several decades, that figure has rapidly plummeted. Recently, the Xerces Society, an international nonprofit focused on the conservation of invertebrates and their habitats, released the results of its Western Monarch Thanksgiving Count, and the news is dire – just 28,429 overwintering Monarchs were counted in California, which is an 86 percent decrease from the count at the same time the previous year.

Washington, Oregon, Idaho, Utah, Nevada and Arizona are seeing similar drops in numbers during the breeding season.

“In addition to fewer monarchs, we’re losing the phenomenon of the migratory behavior,” explains Karen Miner, chief of CDFW’s Biogeographic Data Branch. Miner serves as the chair of the Western Monarch Working Group, a task force consisting of biologists from the seven state agencies. The biologists have been working with experts for months to identify possible causes of the decline, as well as actions that could be undertaken to encourage Monarch population growth.

Unfortunately, there are no easy answers, or easy solutions. According to the Xerces Society report, “the factors that influence Monarch population dynamics in the Western U.S. are still not completely understood.”

In California, some specific factors contributing to the decline of the Monarchs include:

  • Loss of overwintering habitat along the coast. Favorable weather conditions along the California coast attract people as well as the butterflies, and urban development has removed or crowded many of the sites traditionally used by monarchs in the winter. Many of these sites feature eucalyptus trees, originally introduced from Australia in the 1800s. These towering giants historically provided shelter to overwintering Monarchs. But now, the trees are dying of old age as well as the effects of recent drought conditions and disease. Nectaring plants that provide food for overwintering butterflies are also becoming scarce. Protecting and restoring these coastal sites to meet the needs of wintering Monarchs is a top conservation need.
  • The loss of native milkweeds and flowering plants, particularly in the areas where the first eggs would be laid in the spring. Milkweed is a Monarch staple. Butterflies lay their eggs on it, and the emerging caterpillars use it as a food source. Adult butterflies rely on flower nectar for their source of food. As with overwintering habitat, development and land management practices have reduced the amount of milkweed and nectar sources available for Monarchs and other pollinators. Many nurseries and hardware stores sell milkweed, which seems like a Monarch-friendly practice on the surface. But much of the milkweed that’s commercially available to gardeners is non-native, and scientists have noticed that the butterflies attracted to it are more prone to disease, and less likely to migrate to overwintering sites.
  • Complications of a changing climate. Based on annual counts at overwintering sites, the Monarchs that do overwinter are arriving later and leaving earlier. Scientists are concerned that food resources and milkweed for egg laying are not yet available for the Monarchs when they need it. CDFW urges the public to report sightings of Monarchs and the plants they are feeding on to link opens in new windowWestern Monarch Milkweed Mapper. This tool, which also allows citizen scientists to upload photos, will help biologists better understand the distribution and life cycle of both the butterflies and their host plants.

“Can we reverse this? It’s a complicated issue, and it’s going to be hard,” Miner says. “We need to take a number of different approaches. We have to protect overwintering groves, educate the landowners and neighbors of these sites, and we need to improve pollinator habitat including milkweed availability. Each state in the west has a role to play, and so many people can contribute to this effort – citizen scientists, educators, garden club members, agricultural growers, and rights-of-way managers such as utilities or transportation agencies.”

The US Fish and Wildlife Service is currently reviewing a petition to list the monarch under the Endangered Species Act, but the member states of the Monarch Working Group are wasting no time in moving forward with their own efforts to conserve the butterflies. At a meeting of the Western Association of Fish and Wildlife Agencies in January, the group finalized its link opens in new windowWestern Monarch Butterfly Conservation Plan (PDF), which establishes population size and habitat conservation goals, strategies and specific actions. Specific goals include creating an additional 50,000 acres of Monarch-friendly habitat in the Central Valley and foothills, establishing protection and management for half of all currently known overwintering sites, and, ultimately, achieving an average count of 500,000 overwintering butterflies in the west by 2029.

Photos courtesy of USFWS and Xerces Society. Top Photo: USFWS Photo by Ryan Hagerty

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Media Contact: 
Kirsten Macintyre, CDFW Communications, (916) 322-8988

Kyle Orr, CDFW Communications, (916) 322-8958

Categories: Wildlife Research
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