Science Spotlight

Kelly McCulloh loads evidence samples onto a DNA extraction robot.


Jillian Adkins prepares samples for DNA extraction.


Erin Meredith uses a dissecting microscope to isolate hair roots for nuclear DNA extraction.


Ashley Spicer prepares a Polymerase chain reaction used in DNA sequencing.

If they weren’t so busy or their work wasn’t so mission-critical, you might find CDFW’s Wildlife Forensics Laboratory team on loan to the California Department of Education.

The four-person scientific team is all women with undergraduate and advanced degrees in biochemistry, genetics, molecular biology and forensic science.

Jillian Adkins, Kelly McCulloh, Erin Meredith and Ashley Spicer would be stars of state education initiatives to attract more girls to STEM (Science, Technology, Engineering and Mathematics) fields. They would be celebrated at school tours, asked to provide their personal stories at education conferences and inspirational messages in science classrooms across the state.

Instead, this team works mostly out of the spotlight, their scientific analysis critical to CDFW’s law enforcement mission to protect California’s natural resources and provide public safety. Increasingly, CDFW’s Wildlife Forensics Laboratory is being counted on to protect some of the most sensitive animal species on the planet.

“We just don’t lose these cases supported by forensic evidence. It’s amazing,” said Tony Warrington, a recently retired assistant chief who has managed CDFW’s crime lab for more than a decade. “Our forensic specialists do a fantastic job utilizing advanced scientific methods to support wildlife officers with poaching investigations and public safety wildlife incidents.”

Meredith, a senior wildlife forensic specialist with nearly 20 years at the lab, said the mere suggestion by a wildlife officer of sending evidence in for DNA analysis will sometimes prompt poachers to confess to their crimes. The lab is one of only about 10 wildlife forensic labs in the nation, giving CDFW wildlife officers a major crime-fighting assist. Every CDFW wildlife officer can access the lab, which processes evidence in about 100 criminal cases every year.

The white lab coats, antiseptic setting, high-tech equipment and talk of DNA sequencing invite comparisons to “CSI” – Crime Scene Investigations – the long-running night-time television drama that firmly implanted forensics in the public consciousness.

“My joke is always that human forensics is boring – you only work on one species,” Meredith said. “With wildlife, the possibilities are essentially endless.”

First established in the 1970s, CDFW’s Wildlife Forensics Laboratory has taken on a more prominent role with advances in genetic research and technology and the widespread acceptance of forensic evidence in the court system.

“If there’s blood on a knife, not only can we tell whether it’s from a deer, we can also tell whether it’s from a doe or a buck,” Meredith said. “We can tell if the blood on the knife originated from the same deer or evidence taken from a kill site or meat in a suspect’s freezer.”

Said Adkins, “DNA evidence has been a game-changer in determining guilt or innocence – in both people and wildlife.” Adkins’ work in providing quick turnaround of DNA samples allows wildlife officers to use the results to make critical enforcement decisions.

CDFW’s Wildlife Forensics Lab plays a key role in public safety and animal attacks that may involve great white sharks, coyotes, bears or mountain lions. With even minimal DNA evidence, offending species and animals can be identified with certainty in most instances.

“We literally free the innocent – and it’s happened a number of times,” Meredith said. “Our wildlife officers may trap what they think is the guilty bear, draw its blood and bring it to the lab for comparison with saliva from a bite wound or even a scratch mark on the victim. And if that DNA is not a match, that bear gets released.”

Retired assistant chief Warrington said, “This lab completely changed the way we deal with public safety wildlife. DNA matching has allowed CDFW to protect the innocent and positively identify the offending animal in these cases – a big step forward in protecting California’s wildlife.”

The lab marked another milestone in 2015 with the adoption of Assembly Bill 96, which closed a loophole in the state’s ban on ivory and made it illegal to purchase, sell, possess with intent to sell or import with intent to sell ivory or rhinoceros horn – with limited exceptions.

The legislation tasked a state wildlife agency with helping to combat the global ivory trade in order to protect ivory bearing species from poaching, exploitation and extinction worldwide. AB 96 provided funding for CDFW’s Wildlife Forensics Lab to add a fourth scientist in McCulloh.

McCulloh arrived with a master’s degree in forensic science from UC Davis. She has pioneered California’s genetics test for ivory products. It’s so accurate, it can distinguish African elephant ivory from Asian elephant ivory and even ivory from a long-extinct woolly mammoth.

Spicer, a native of British Columbia with degrees in biochemistry and forensic science, specializes in the physical characteristics of ivory that distinguish it among the many different ivory-bearing species – from elephant and hippopotamus to sperm whale and warthog – and also from non-ivory products such as synthetic ivory or plastics made to look like ivory. 
Spicer personally has worked on 17 of the 18 criminal ivory cases that have come through the lab since AB 96 was enacted. Her work has included serving as an expert witness and testifying at trial.

The lab’s contributions were heralded recently in the conviction of a Los Angeles County business owner on charges of selling two ivory tusks from Arctic narwhal whales. The tusks measured 79 and 89 inches long.

CDFW’s forensic scientists don’t necessarily mind all the newfound recognition – as long as the focus remains on their work.

Said Spicer, “We are really committed to the highest standards and ideals of science.”

YouTube Video Link: https://youtu.be/4KS4e3ILKOw

CDFW Photos. Top Photo: The four-woman forensics team.

California Fish and Game, Volume 104, Issue 2, is now available online! California Fish and Game is CDFW's official, quarterly, scientific journal devoted to the conservation and understanding of the flora and fauna of California and surrounding areas, and the eastern Pacific Ocean.

A mallard in flight appears on the cover of the newest installment of the journal. With its iridescent green head and school bus yellow legs, the male mallard is one of the most recognizable species of duck in California. It is also the most abundant breeding species of waterfowl in the state. However, California’s mallard population estimates have generally declined since the mid-1990s. In California mallards: a review, Feldheim et. al synthesizes volumes of research in an effort to identify long-term research needs and monitoring activities to help improve management of this iconic species.

In another paper, entitled Abundance, habitat and occupancy of Roosevelt Elk in the Bald Hills of Redwood National Park, Tolliver and Weckerly seek to understand the relationship between a species’ occupancy-abundance rate and its habitat use. Using elk sign surveys (i.e, counting tracks and feces at standardized locations) researchers found that, as population density increases, Roosevelt elk will move into other (lower quality) habitats. This was true for two herds of vastly different sizes, although the occupancy rate remained comparable.

Finally, Hiney et. al looks at recruiting experienced anglers and using citizen science to help document and survey the native Coastal Rainbow Trout population of Grass Valley Creek Reservoir. The authors look at methods of overcoming the time and resource limitations of assessing wild trout populations.

Also included in this issue are reviews of two books that make meaningful contributions to the field of wildlife research.

As it has for the past 104 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 staff and volunteers set a one-day record of 1.5 million eggs collected on the Little Truckee River earlier this month.


CDFW staff and volunteers use seine nets and electric fishing techniques to corral and capture adult Kokanee salmon.


Volunteers from the California Inland Fisheries Foundation, Inc. and Kokanee Power help CDFW personnel capture Kokanee salmon.

Each October, conditions permitting, CDFW staff and volunteers from the California Inland Fisheries Foundation, Inc. and Kokanee Power descend on the Little Truckee River, just upstream from Stampede Reservoir near Truckee, and get to work on the annual Kokanee Egg Take.

Using seine nets and electrofishing techniques to corral and capture adult Kokanee Salmon, staff and volunteers then collect eggs and milt (fish semen) add them together in specific ratios to complete the spawning process. The fertilized eggs are carried to an egg care station on the side of river where they are measured, enumerated, disinfected and finally placed in containers to be transferred to the San Joaquin Hatchery.

Staff at San Joaquin Hatchery incubate, hatch and care for the early-life stages of the resulting baby salmon. Some fertilized eggs are shipped to other CFDW hatcheries for hatching and rearing. Resulting fingerling fish are stocked to several approved waters in the state to provide recreational angling opportunities.

“By all accounts, this year set the one-day egg take record of 1.5 million eggs,” said Roger Bloom, CDFW’s Inland Fisheries Program Manager. “This was a collective effort from our scientists, hatchery staff and stakeholders that culminated into actions in support of fisheries across the state. Given the magnitude of eggs taken on that record day, it took a non-stop effort of over 23 straight hours to get the job done, which highlights the dedication and resolve CDFW personnel have -- especially the hatchery staff who now will care for these eggs that will eventually grow to be little salmon!”

Kokanee Salmon were introduced into California waters to provide diverse recreational angling opportunities for anglers and have become an extremely popular sport fish. They are typically smaller than the landlocked Chinook Salmon, with an average size of about 12 inches. This summer, CDFW will release the Kokanee Salmon fingerlings that emerge from this collection effort into lakes and reservoirs throughout the state.

The landlocked version of the Sockeye Salmon, the Kokanee (pronounced coke-a-nee) Salmon spends its entire life in fresh water. Instead of migrating to the ocean, adult Kokanee Salmon inhabit large lakes before returning to their natal streams or gravelly shorelines to spawn. Like all Pacific salmon, Kokanee die after spawning, the whole life cycle taking from two to four years.

CDFW Photos. Top Photo: Volunteer holds a Kokanee salmon during work on the Little Truckee River.

Close-up of adult spring-run Chinook salmon dorsal fin.


Adult spring-run Chinook salmon inform river restoration decisions by their habitat use and preferences.


Adult spring-run salmon are carefully selected for release based on their sexual maturity.


Spring-run Chinook salmon released into the San Joaquin River are outfitted with three tags including a colored T-bar tag for visual identification.

Fresno County may seem an unlikely setting for salmon restoration and research, but some of the California Department of Fish and Wildlife’s (CDFW) most ambitious work with salmon anywhere is taking place in the heart of the parched Central Valley.

Since September, CDFW fisheries biologists have been spawning spring-run Chinook Salmon broodstock in the shadow of Friant Dam on the San Joaquin River. This season, CDFW staffers spawned 100 mature females that ranged in age from 3 to 6 years old  producing about 290,000 eggs.

It’s all part of an unprecedented, multiagency effort to restore an extinct, spring-run Chinook Salmon run to the San Joaquin River that is happening alongside river restoration efforts to make the river more salmon-friendly for a fish listed as threatened under both the state and federal Endangered Species Act.

Historically, spring-run Chinook Salmon were the most abundant salmon species in the Central Valley. Today, there are so few fish broodstock used for spawning comes from eggs collected at CDFW’s Feather River Hatchery in northern California. Meanwhile, construction is underway on a spring-run Chinook Salmon hatchery at the base of Friant Dam to support future runs of San Joaquin River salmon. The hatchery is scheduled to be completed in 2019.

During spawning, each female is crossed with four males to maximize genetic diversity. Samples of ovarian fluid are collected and sent to the CDFW’s Fish Health Lab for virology and bacterial analyses. Any egg lots determined to be potentially infected with pathogens are excluded from CDFW’s captive rearing program.

In June and August, 179 captive-reared adult fish – 59 females and 120 males – were released into the San Joaquin River to monitor what parts of the river the salmon prefer for holding and natural spawning.

Prior to release, each fish was outfitted with three tracking devices – an electronic passive integrated transponder (PIT) tag for individual identification, a colored, T-bar tag for visual identification, and an acoustic transmitter so their movements in the river can be monitored and recorded. Their habitat use and preferences inform river restoration efforts.

Spring-run Chinook Salmon spawn in the fall from mid-August through early October. So far, biologists have found 37 constructed redds – or salmon nests – in the San Joaquin River indicating some of the released salmon found enough cool water in the heavily damned and diverted river system to survive the Central Valley’s furnace-like summer and are now actively spawning in the river.

CDFW Photos by Travis VanZant. Top Photo: Prior to their release into the San Joaquin River this past summer, adult spring-run Chinook salmon were outfitted with acoustic transmitters so their movements in the river can be monitored and recorded.

Researchers built 90 hair-snare stations designed to pull a small hair sample from black bears that cross the snares.


The Warner Mountains Black Bear Project study area (blue boundary) and layout of hair-snare grids (yellow squares) in northeastern California. The upper-left inset shows the southernmost hair snare grid and layout of hair-snare locations (red circles). Density estimates and information on habitat from within the 10 grids will help researchers estimate overall black bear abundance across the entire study area.

California’s black bear population is healthy and growing, with an estimated 35,000 animals, up from an estimated 10,000 to 15,000 in 1982. But how do wildlife biologists determine these figures – and why are they important?

Deep in the Warner Mountains in Lassen and Modoc counties CDFW is just completing the first year of a study of black bears. The lead scientist, Steffen Peterson, explained that anecdotal evidence in recent years – including increased bear sightings by both field scientists and everyday citizens, as well as an increased number of requests for depredation permits due to bear-human conflicts – seemed to indicate that the population of black bears in the Warner Mountains was booming and this area would be ideal for scientific research.

According to Peterson, the two primary objectives of the Warner Mountains Black Bear Project are to estimate black bear abundance in the study area and to determine how black bears use the landscape. This kind of information on black bear demography and space use is essential for wildlife managers to make scientifically sound bear management decisions for this region of California.

CDFW is using a genetic capture-recapture method to estimate the population size. Usually, this involves physically capturing an animal, marking it in some way and releasing it. But this particular study achieves the same goal with non-invasive techniques – specifically by using hair snares, which cause relatively little stress or harm to the animals. Hair snares have been used on many furbearing species to determine presence, to calculate a minimum absolute count of individuals present, or to estimate total population size by collecting a DNA sample from individuals without physically capturing the animal. Unique repetitive sequences, known as microsatellites, within the DNA sample serve as individual identifiers, making it possible to know when and where each unique animal was present.

In addition, because the DNA located within roots of mammalian hair can identify species, sex, and individuality, this genetic technique is ideal for researchers to estimate abundance as well as obtain information on demographics and genetic diversity.

Peterson, a CDFW scientific aid and a Humboldt State University graduate student, and other researchers built 90 hair-snare stations distributed across 10 sampling grids that that are designed to pull a small hair sample from bears that cross the snares.

The contraption consists of two parallel strands of barbed wire stretched around a cluster of three or more trees, one about eight inches off the ground and the other about 20 inches off the ground. This forms a barbed-wire “corral” in which researchers place a pile of logs drizzled with fish oil. The oil acts as an attractant to black bears, who have both a finely attuned sense of smell and a profound love of fish. At two thirds of the hair-snare stations, researchers placed a trail-camera to help verify the effectiveness of the snares at capturing hair samples when a bear is present. The trail photos also provide demographic (cub-adult ratio) information on bears within the study area.

“The use of hair-snares to collect genetic data for abundance and density estimates has become the gold standard for American black bear,” said Peterson. “The hope is for the bear to cross between the two strands of barbed wire, although some of our video footage from the trail cameras shows bears crossing – even jumping, in some cases –  over the wire. Because bears are big, robust animals, for the most part they pay little mind to the barbs and typically cross them, leaving us a nice big clump of hair. Bears are the ideal critter for hair-snares in this way.”

Although Peterson stressed that it is much too soon in the study process to draw conclusions about the number of black bears living on the grid, initial results indicate that, at a bare minimum, black bears are certainly roaming throughout the study area.

During a 50-day hair collection period that took place this summer, black bears were detected in all of the grids created in the study area that encompasses roughly 600 square miles of high desert terrain; researchers collected 469 samples of hair in all at 57 of the 90 hair-snare locations.

“Long story short, we are pleased by the amount of detections observed during our data collection,” Peterson said. “Good detections will strengthen our ability to estimate density within each grid which will allow us to more reliably estimate abundance off the grid – i.e., the Warner Mountain study area as a whole.”

Peterson is now set to begin the DNA analysis phase on the samples collected. This will allow him to determine precisely how many individual bears left hair behind (bears often leave more than one sample at a snare location and some individuals are repeat visitors), as well as information on gender and habitat use, including the movement of bears across the study area.

Next summer, project staff will capture and collar 12 adult black bear with research collars, which will record hourly GPS locations of the bears as they move across the landscape, providing information on how they use the landscape, including seasonal habitat preferences and, during the winter hibernation period, where bears den.

“This information will greatly improve our knowledge of how bears use these high desert ecosystems, characteristic of the Great Basin, and guide future land management in this region,” Peterson said.

The project is expected to continue for another two to three years. ###

CDFW Photos. Top Photo: Emily Monfort, a CDFW scientific aid, carefully removes black bear hair from barbed wire at a hair-snare location. The DNA from this clump of hair will be examined in the laboratory to determine the sex and genetic identity of the black bear that crossed this wire.  Photo credit Korrina Domingo (CDFW).