Science Spotlight

A newly collected female wild white abalone releases eggs during the captive breeding program’s annual spawning event. This was the first new genetic input in the captive population for 14 years. Photo taken for CDFW by M. Ready

At nearly 130 feet underwater, CDFW abalone researcher Dr. Laura Rogers-Bennett didn’t have much time. Her dive computer told her it was time to ascend, which meant that she would have to stop searching for the endangered white abalone hiding in the waving fields of red and gold gorgonians.

Reluctantly, she watched the beautiful scene drop away below her as she kicked slowly upwards. She moved through the towering elk kelp towards her safety stop, a precious white abalone kept solidly in her grasp. On that trip, back in 2004, Rogers-Bennett and Ian Taniguchi, another CDFW abalone expert, and a team of other scientist divers collected 21 critically endangered white abalone off the deep reefs in the Channel Islands. This collection trip was conducted in an effort to save the species before they disappeared from the wild, and to create a captive breeding program that could bring this important and iconic species back from the brink of extinction.

Fourteen years later, the white abalone Captive Breeding Program is a thriving reality, thanks to the vision and hard work of a committed team of scientists from the White Abalone Consortium (WARC). Those 21 animals that Rogers-Bennett helped to collect in the Channel Islands have now produced thousands of descendants in captivity. The program is so successful, in fact, that it is now producing more animals than it has space to raise. Now, the next step is for WARC and CDFW scientists to perfect methods to release these captive bred animals back into the wild.

A huge challenge for CDFW and the WARC is to ensure that the captive-bred animals stand the best chance for survival in the wild – and one of the greatest obstacles could lie within the abalones’ own DNA. Because the entire captive-bred population stems from only 21 animals, the genetic diversity of the captive program is limited. One of the main factors that influence how a population of animals will react to stress is how genetically diverse the individuals are from one another. 

In the past, wild, healthy white abalone populations had large numbers of individuals to reproduce with. This created a vast number of family lineages and resulted in an expansive genetic pool. A population with diverse genetic parentage strengthens the overall population by ensuring that there will be a diversity of responses among the individuals. For example, some stresses, like disease or environmental change, may affect certain individuals while others maybe be more genetically suited to defend against those threats. If the population faces a major disease outbreak, some individuals will likely survive, enabling the populations to restore itself over time. But if a population lacks this genetic diversity due to limited parentage, the entire population could succumb to the disease.

The solution is to introduce new animals into the captive breeding population in order to diversify the gene pool and create animals vigorous enough to thrive in the wild. Yet that’s a trickier proposition than one might think, because of their endangered status. Even when evidence strongly suggests that there has been zero reproduction, researchers follow very strict guidelines so as not to disrupt potentially viable populations. For this reason, WARC and CDFW spent years monitoring reproduction of wild white abalone populations, until they were absolutely certain that the animals were not reproducing in the wild.

In 2017, the WARC was given a permit by NOAA to collect wild animals for the captive breeding program. The following May, when conditions were right, Rogers-Bennett and the WARC team of scientists returned to the Channel Islands on the first white abalone collecting trip in more than a decade. WARC divers gathered in the spring sun on the deck of the research vessel Garibaldi to discuss the day’s dives, which would be to nearly 120 feet. Everyone was focused, but a cautious optimism hung in the air. Encountering the incredibly rare white abalone was a long shot, but two individuals had been spotted in the area within the last year.

Alongside her team, Rogers-Bennett descended through the water column, watching as the ocean floor came into focus below her. As she got closer, she could just make out the familiar shape of an abalone. She assumed it was another, more common species of abalone, but as she got lower she recognized the unmistakable markings of a white abalone. She had landed directly on top of one!

Since the beginning of 2017, 10 animals have been collected by WARC scientists and transported to their facility in Bodega Bay. This is the first time in 14 years that scientists will be able to add new genetics to the captive breeding program. Dr. Kristin Aquilino, Director of the UC Davis Captive Breeding Program for the WARC, was able to include a newly collected female white abalone into the 2017 annual captive breeding spawn. It takes time before wild animals are able to integrate into the program, but researchers hope that the newly collected animals will participate in the next white abalone broodstock spawn.

With the new genetics from the wild abalone being introduced to the captive breeding program, and restorative stocking studies underway, the future for this species is looking brighter all the time. Through the dedication of a brilliant team of scientists, policymakers and an engaged public, the WARC is hopeful that one day the white abalone will resume its ecological role in the deep reef ecosystems of the beautiful Southern California kelp forests.

Please stay tuned for more updates about the white abalone and our other abalone restoration work in California!

CDFW Photos. Top Photo: CDFW diver Ian Tanigucci takes notes before collecting a wild white abalone (in the foreground) in 2017. This is one of 10 white abalone collected from the wild to be integrated into the captive breeding program at Bodega Marine Lab. These newly collected animals will provide a new and much needed source of genetics for the captive bred white abalone populations.

Ready for release.


Heading back out to the open water.

CDFW Senior Environmental Scientist Mike Harris is credited with the rescue of a green sea turtle that was unintentionally caught from a pier in Morro Bay.

Harris and the Morro Bay Harbor Patrol responded to a report of the hooked turtle on Aug. 17, after Harris was alerted by a friend in the area.

He arrived to find the angler had carefully secured the turtle and was waiting for help. He noticed the fishing line with a swivel was sticking out of the turtle’s mouth and determined the hook could not be easily removed.

Harris shares work space in Morro Bay with The Marine Mammal Center (TMMC) triage facility, positioning himself well for marine wildlife response. Coincidentally, the TMMC Morro Bay veterinarian is Heather Harris, Mike’s wife, who happens to be an expert on sea turtles.

“She was the first person I called,” he said.

Veterinarian Harris stabilized the turtle and determined it needed surgery since the hook was lodged deep in its throat. Not having the proper equipment and supplies for this type of surgery at the triage site, Heather reached out to colleagues at the Aquarium of the Pacific in Long Beach to arrange for the required care.

The green sea turtle was transported that afternoon and underwent surgery for the hook removal the same day. The hook was successfully removed, the turtle was provided antibiotic treatment and, after several weeks of rehabilitation, was released back into the wild on September 18th.

Harris said the rescue was made possible by the great working relationship between CDFW, TMMC, other agencies and the public.

“Over the past 20 years, I’ve built a connection with the community,” said Harris. “Whether it’s whales, dolphins or sea otters, the public and local agencies often call me to report these types of wildlife events.”

Harris has worked in the Morro Bay area for more than 27 years and is one of two sea otter biologists that work for CDFW’s Office of Spill Prevention and Response (CDFW-OSPR) Marine Wildlife Veterinary Care and Research Center (MWVCRC).

The MWVCRC is a one-of-a-kind lab built in 1997 and focuses on the rescue, rehabilitation and research of oiled marine wildlife, with emphasis on sea otters. California lawmakers created OSPR in 1991 due to several major spills including the Exxon Valdez in 1989. The lab is funded by a fee on petroleum entering California refineries.

Photos Copyright Aquarium of The Pacific. Top Photo: Rescued green sea turtle.

Northern watersnakes are native to the eastern United States. A breeding population was discovered in Placer County in 2007 and a second population confirmed in 2014. Photo courtesy of Todd Pierson.


Coqui frogs have appeared periodically in Southern California. The first coqui was collected from a private residence in Orange County in 2012 and arrived on a tropical house plant.


Nutria have been confirmed in six central California counties, including Tuolumne County where this nutria was photographed near Don Pedro Reservoir in 2017. Photo courtesy of Peggy Sells.


Southern watersnakes are native to the southeastern United States and can reach lengths of 5 feet. They have been found in Yolo, Sacramento and Los Angeles counties. Photo courtesy of Todd Pierson.

Six months after announcing the discovery of a breeding population of invasive nutria in the San Joaquin Valley, CDFW’s Invasive Species “hotline” continues to receive multiple reports each week of nutria sightings from the public.

The reports come in on the toll-free line – (866) 440-9530 – or its e-mail counterpart – Invasives@wildlife.ca.gov – and numbers have reached as many as 30 e-mails and nine calls in a day.

The hotline accounts are checked each weekday – and often multiple times a day. CDFW attempts to respond to every individual submission. To date, about 95 percent of the nutria reports have turned out to be false – either sightings of other wildlife mistaken for nutria or reports that lack enough information to confirm one way or another.

“If it’s on your roof or chewing up the wires in your car, it’s not a nutria,” said Helen Benson, an environmental scientist with CDFW’s Invasive Species Program.

The misidentification of nutria is understandable. Nutria closely resemble several species of native and non-native wildlife, including muskrats, beavers, and rats, which adds to the challenge of a positive identification. Nutria are semi-aquatic rodents native to South America that haven’t been seen in California for 40 years until the spring of 2017 when a pregnant female turned up in a beaver trap.

Still, CDFW welcomes and encourages all reported sightings, preferably accompanied by a photo or video to help verify the identity.

In April, the hotline received one of its most important tips when an Animal Services officer with the City of Lathrop called to report catching and releasing a nutria – without realizing what it was at the time. The officer took photos of the animal, however, which became the second nutria confirmed in San Joaquin County on the edge of the Delta.&

CDFW has focused its early eradication efforts on keeping nutria out of the Delta, where their destructive burrowing into levees, ditches, canals and other water infrastructure could jeopardize the Delta’s flood control and water conveyance systems. CDFW has since launched nutria surveillance and eradication operations in the Delta to mirror those occurring farther south in the San Joaquin Valley.

While CDFW’s Benson estimates that about 80 percent of the Invasive Species hotline’s reports involve nutria these days, the hotline itself predates the nutria infestation by more than a decade. It was created in 2007 to help combat another invasive species crisis: the discovery of quagga and zebra mussels in California.

“Most people don’t realize that invasive species are the second-greatest threat to native species after habitat loss,” Benson said.

It’s easier to combat and possibly eliminate invasive species early before populations become entrenched, which explains CDFW’s aggressive nutria eradication response.

Coqui frogs are another invasive species dealt with quickly when reports come into the hotline. The voracious, tiny tree frogs native to Puerto Rico, Central and South America emit a deafening raucous that belies their small size. The call from one of these tiny amphibians can reach noise levels of 80 to 90 decibels – the same as a running lawnmower. Colonies of coqui frogs have been blamed for lowering property values on Hawaii’s Big Island.

Coqui frogs have turned up in Southern California, arriving in nursery plant shipments from Hawaii and other exotic locales. CDFW asks those contacting the hotline to record the frogs’ calls for confirmation, at which point CDFW will dispatch biologists to catch and remove the frogs.

The Invasive Species hotline has also proved helpful in combatting two invasive aquatic snakes that have turned up in Northern California – the northern watersnake and southern watersnake – likely released into the environment by disenchanted owners who acquired them as pets. Their ill temperament and unpleasant odor make them poor pets – along with the fact they are illegal to possess in California without a permit. CDFW has launched trapping efforts in the suburban Sacramento communities of Roseville and Folsom, where breeding populations of the snakes have been confirmed. It’s possible these snakes could find their way to backyard ponds and swimming pools, and reports to the hotline would help CDFW’s efforts to eradicate them.

Invasive species are a persistent threat to California, and the public plays an important role in helping CDFW identify and respond to new threats. Whether in their backyard or hiking their favorite trail, everyday citizens across the state are partners in protecting their natural resources by reporting unfamiliar plants and animals they don’t recognize.

CDFW Photos. Top Photo: Juvenile Coqui frog.

Veterinary staff assess deceased deer


Veterinary staff take samples of deceased cervid


Veterinary staff take samples of deceased cervid

CDFW scientists, wildlife officers and other staff are pulling out all the stops to fight a wildlife disease of major concern from crossing state lines and infecting native deer and elk populations.

Chronic Wasting Disease (CWD) is a contagious, always-fatal neurological disease that affects cervids (deer, elk and moose). In North America, the disease is currently found in captive and wild cervid populations in 24 U.S. states and two Canadian provinces. It has been detected in captive elk and sika deer in South Korea and free-ranging reindeer, moose, and red deer in Norway and Finland.

To date, a combination of legislation and geography have kept this disease at arm’s length from California, but the threat is still very real.

“All of us – scientists and wildlife managers, landowners and hunters – need to join forces and work together to keep this disease out of California, or the future could be disastrous for our native herds,” said CDFW Wildlife Veterinarian Brandon Munk, who participates in a multi-agency task force to fight CWD.

For California, this means two things: continuing to enforce strict cervid (animals and parts) importation and movement regulations, and ramping up disease surveillance efforts. This deer season, CDFW will be setting up voluntary check stations for deer hunters throughout California. Here trained staff will collect lymph nodes from the neck of harvested deer – a process that takes only minutes and is minimally invasive to the surrounding tissue. While waiting, hunters can get their tags validated and learn more about how to help prevent the introduction of CWD to California.

Once established, CWD is notoriously difficult to fight. The disease is spread by direct contact with infected animals or environments contaminated by the infectious agent called “prions.” Environmental contamination seems to play a very important role in the spread and maintenance of this disease. Once the environment is seeded with these prions, eradication is difficult – if not impossible – as prions are extremely difficult to remove from the environment or to disinfect. Prions can also remain infectious in the environment for years. Even controlled burning and freezing temperatures do not remove the threat. Most attempts to eradicate this disease have failed, and scientists in other states have had limited success in their efforts to control its spread.

CWD is also difficult to detect, in part because the outward signs often do not manifest until several years after initial infection. Currently, there is no effective live-animal test and there is no vaccine. Systematic testing of hunter-harvested deer is one of the most widely used surveillance methods available. Additionally, it is one important method to help ensure the disease has not entered the state and will help ensure CDFW can detect CWD early should it ever reach California. Early detection of CWD is the first and most important step to effective management of this disease.

CDFW has established a Chronic Wasting Disease Task Force to lead efforts preventing the spread of CWD to this state. Members include CDFW staff (biologists, veterinarians, communications officers and wardens), Fish and Game Commission employees and California Animal Health and Food Safety veterinarians. The task force is reaching out to the public and other local, state, and federal agencies to help with surveillance efforts, educating sportsmen about how they can do their part to prevent the spread of CWD and preparing a comprehensive management plan to allow for rapid response if the disease ever does make it to California.

“We are very lucky that to date, no California deer or elk has tested positive for CWD – but we’re not taking it for granted,” Munk said. “We urge hunters to educate themselves about this very real threat, and to do their part to make sure that we keep it out of California.”

CDFW has produced a short video on preventing the spread of CDFW, including a demonstration on antler removal and proper butchering techniques. You can also find background information, additional links and updates on California’s efforts to fight CWD at www.wildlife.ca.gov/CWD.

To find a CDFW check station to get your deer or elk checked, please visit www.wildlife.ca.gov/CWD or call (916) 358-2790.

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CDFW Photos. Top Photo: Veterinary staff takes and examines samples from deceased deer.