Science Spotlight

Joe Millosovich, an environmental scientist who specializes in lake and fisheries management in the Central Valley, came all the way from Fresno to captain one of the electrofishing boats collecting bass in the Delta Jan. 16. Several of CDFW’s biologists participating in the outing called it one of their favorite days of the year.


Max Fish, an environmental scientist with CDFW’s Inland Fisheries Program, captained the electrofishing boat that collected the largest largemouth bass of the morning – a 10-pound-plus whopper.


Kyle Murphy, a senior environmental scientist with CDFW’s Inland Fisheries Program, shows off two of the larger Delta largemouth bass headed for the International Sportsmen’s Exposition demonstration tank in Sacramento.

Among the more popular attractions at the Sacramento International Sportsmen’s Expo each January is the Western Bass Aquarium Demo Tank. The 6,000-gallon aquarium displays dozens of trophy largemouth bass collected by CDFW biologists from the Sacramento-San Joaquin Delta. The aquarium demo tank, with bleachers on both sides, is where professional bass anglers lead seminars demonstrating the latest techniques and can’t-miss lures – all without hooks attached so as not to injure the fish.

“This is the best display of largemouth bass anywhere in the country,” said Kent Brown, the longtime host of the ISE demonstration tank. “And that’s not just me talking. That’s from tournament bass fishermen who travel all over the country. There’s just no bass anywhere that can rival these Delta bass.”

The tank is also a tremendous source of pride for the CDFW fisheries biologists tasked with collecting the fish.

“It’s great for people to see the kind of fish they can catch here in their own backyard,” says Ben Ewing, a CDFW district fisheries biologist who headed the ISE collection effort this year. “All the fish get released back into the Delta immediately after the show and literally are available for anyone with a fishing license to catch.”

A mix of 16 fisheries biologists and volunteers assembled along the Delta near Stockton the morning of Jan. 16, the day before the opening of the four-day ISE show at Sacramento’s Cal Expo. They climbed onto four electrofishing boats to probe likely largemouth hideouts – tule stands, rip-rap shoreline, sunken boats, submerged tree limbs and other structure.

“We all come together to try and make a good display for the public,” Ewing said.

Over the years, a friendly competition has developed. A trophy and bragging rights go to the CDFW boat captain who collects the largest bass for the show. Each of the four captains took off with their crews in different directions searching for a largemouth bass that might not only win the day but one that might top their all-time ISE show record fish of more than 13 pounds.

The boats sent targeted currents of electricity through the water while crew members standing on the bow were ready with nets to scoop up the stunned fish for deposit into the live wells for safekeeping. In more than 20 years of providing Delta largemouth bass for the Sacramento ISE show, CDFW biologists have refined their methods and strategies.

In addition to looking for the largest fish, a mix of sizes is collected. Smaller bass add perspective in the tank and make the biggest fish look even bigger. Suckers, catfish and large sunfish add some fun diversity to the display. Striped bass are a no-go – they don’t do so well in transport and they’ve been known to jump out of the aquarium.

Max Fish, an environmental scientist with CDFW’s Inland Fisheries Program, piloted one of the electrofishing boats. He explained how these vessels are important research tools that allows CDFW scientists to survey fish populations and assess health in the state’s lakes and reservoirs. CDFW puts one of the boats on display at the ISE show each year and points out the connection between the boat and the bass in the tank.

On that overcast January morning with major winter storms looming in the forecast, Fish sent 340 volts of electric current through the shallow Delta waters. The conditions for electrofishing were nearly ideal – the plentiful organic material in the Delta helps conduct electricity while the overcast skies were unlikely to spook fish and send them deep beyond the boat’s effective reach.

Fish said the boat’s electric current ranges about 10 feet deep and about 20 feet wide – roughly the span between the two sets of anodes extending from the boat’s bow into the water.

Fish’s efforts were rewarded with the largest bass of the day – a 10.3-pound lunker among others in the 9- and 8-pound class. After congratulations, photos and good-natured ribbing from his colleagues back at the dock, the 60 or so fish collected by all the boats were shuttled directly to Sacramento’s ISE show in an aerated live well.

Meeting them there was CDFW veterinarian and fish pathologist Keven Kwak, who tested and treated the aquarium’s water to make sure it was safe for what would be the fish’s short, but celebrated stay in Sacramento.

CDFW Photos. Top Photo: CDFW biologists stand ready with nets in hand to scoop up temporarily stunned fish for the ISE’s bass fishing demonstration tank in Sacramento. Biologists look for the biggest and best specimens to showcase the Delta fishery. While the biologists are targeting largemouth bass primarily, the electric current brings up carp, catfish, suckers, striped bass and all manner of sunfish. Within a minute or two, the stunned fish come to and swim off.

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

Christmas can be the gift that keeps giving -- to anglers and fish alike.

In the north state, CDFW fish habitat technicians oversee the collection of discarded Christmas trees, which will be used to build underwater habitat structures for local waterways. Long after they’ve brightened holiday homes, these trees will provide shelter for juvenile warmwater fish species -- and ultimately will create better fishing opportunities for anglers.

According to Joseph Rightmier, a fish habitat supervisor with CDFW’s Fish Habitat Improvement Shop in Yreka, the trees are weighed down with cables and submerged, creating a refuge for juvenile fish, including Largemouth Bass and crappie.

“The fish get into the voids within the structure, which gives them some protection. And when you attract smaller fish, you also end up attracting larger, catchable fish, which hang out close to the surface and wait for a meal,” Rightmier said.

“Divers have determined that fish start congregating in and around the structures within a day or two of the habitat structures being installed. They’re hot real estate in the water!”

One of the largest efforts to collect and “upcycle” trees is conducted by Rightmier’s team in Siskiyou County. Last summer, staff used trees collected after the 2017 holidays to create and then place 22 habitat structures into Green Springs Reservoir in Modoc County. The habitat structures were comprised of approximately 200 recycled Christmas trees and small junipers. The Christmas trees were collected at drop-off locations in the cities of Alturas and Yreka, and the small junipers were harvested in the Modoc National Forest.

In 2018, Rightmier said, the Yreka fisheries habitat technicians also used trees to build fish habitat structures in three other locations: Juanita Lake, Orr Lake and Trout Lake. Similar projects have also been conducted at Lake Shastina and Dorris reservoir in the past.

Further south, CDFW’s Redding office is also overseeing a Christmas tree collection operation. The tentative collection location will be in the town of Chester, and the trees will be used for a project in Lassen County.

“Generally, we prefer hardwoods when doing habitat projects, but we do use Christmas trees when they’re available,” explained Monty Currier, an environmental scientist with CDFW’s Reservoir Program. “The trees would go a landfill to be chipped otherwise, and we believe that recycling is a better idea. And people are happy to help CDFW with this kind of habitat improvement project – who doesn’t like the idea of making our fisheries better?”

Currier is currently working with a local bass fishing group and county officials to determine a specific tree dropoff point.

Donated trees should not be flocked, and should be stripped of lights, tinsel and ornaments. The trees are usually transformed for their new use within a couple of months, before they dry out completely.

“Our fish habitat shops enjoy doing this type of project, and it makes a real difference in how successful anglers are,” Currier says. “Everybody wins – not just the fish!”

###

Interested in recycling your Christmas tree in Siskiyou, Plumas or Modoc counties? Drop-off locations for Christmas trees will be located near the CDFW offices in Alturas (702 East Eighth St.) and Yreka (at the corner of Ranch and Oregon streets, due west of the CDFW yard). In Chester, the location has not yet been determined, but you can call the main office at (530) 225-2300 for information closer to the holiday.

CDFW Photos. All Photos: Fisheries biologists placing recycled Christmas trees into Mountain Meadows Reservoir, Lassen County, to create habitat for juvenile fish.

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.

###

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