Science Spotlight

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  • August 2, 2019

Creek running through hilly, riparian habitat filled with trees and bushes.
Rock Creek, where Shasta Crayfish were released by hand July 15.

Bucket filled with small crayfish.
Shasta Crayfish await delivery into their new home in Rock Creek. The Shasta Crayfish is a small- to medium-sized crayfish found only in northeast California.

White bucket with several crayfish.
Establishing populations of Shasta Crayfish in suitable water bodies that are inaccessible to invasive crayfish is the central effort in conserving the species.

Closeup of white bucket with several crayfish.
The mix of 28 Shasta Crayfish introduced into Rock Creek included both juveniles and adults of varying sizes.

A 20-year, multiagency effort to find a safe haven for California’s only remaining native crayfish culminated recently with the release of 28 Shasta Crayfish (Pacifastacus fortis) into a restored section of Rock Creek in Shasta County.

The Shasta Crayfish has been in decline and under assault for decades from the pervasive, nonnative, invasive Signal Crayfish (Pacifastacus leniusculus), which not only outcompetes it for food and habitat but renders Shasta Crayfish females largely infertile through interbreeding. Found only in northeastern California, the Shasta Crayfish was listed as an endangered species by both the state and federal governments in 1988.

It was all smiles and optimism for a brighter future July 15, however, with the release of the 28 adult and juvenile Shasta Crayfish into a formerly dry, meadow portion of Rock Creek on property owned by Pacific Gas and Electric Company. That portion of Rock Creek, just six-tenths of a mile long, now flows with a reliable supply of cool, clear water with habitat enhancements that include rock clusters and riparian plantings.

Restoration of Rock Creek was completed in 2016 through a partnership with PG&E, CDFW, the U.S. Fish and Wildlife Service and the biological consulting firm Spring Rivers Ecological Sciences LLC.

Spring Rivers scuba divers collected Shasta Crayfish from the bottom of nearby Crystal Lake in June. Crystal Lake is believed to hold the most genetically robust population of Shasta Crayfish left in the wild but a population that’s also in decline as a result of the invading Signal Crayfish. The Shasta Crayfish were quarantined for 42 days before release into their new home.

Key to the Shasta Crayfish’s recovery as well as its biggest obstacle is establishing populations in waters inaccessible to the invasive Signal Crayfish. The refuge at Rock Creek was 20 years in the making by the time the site was identified, project proposals prepared and approved, permits secured, partnerships formalized, restoration work completed and the Shasta Crayfish translocated last month.

Restoration of the creek involved major construction removing a diversion dam upstream and rerouting a pipeline that supplied CDFW’s Crystal Lake Hatchery with water downstream. The location was deemed ideal as CDFW’s fish hatchery would block any Signal Crayfish in Crystal Lake from moving up into the restored portion of the creek.

In their new Rock Creek refuge, the Shasta Crayfish will be closely monitored. The hope is that they can serve as a sustainable, genetically diverse source population for future introductions.

CDFW Photos. Top Photo: Divers carefully released Shasta Crayfish by hand into their new home July 15. Prior to release, biologists measured and recorded their size and other data.

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

Categories: General
  • June 11, 2019

Lake with vegetation in foreground. Snowy mountains and green trees in background.
A long, wet winter has been good for Junction Reservoir and CDFW’s Kamloops rainbow trout that live there.

Dock on lake with small fishing boats. Mountainside with trees in background.
The June Lake Marina graciously offered up its net pens to CDFW’s Kamloops rainbow trout program when the drought forced CDFW to rescue its brood stock from a shrinking Junction Reservoir.

Two men in CDFW uniforms standing in concrete and metal structure in stream. One man is holding a large white net. Trees and patchy snow covered ground in background.
CDFW hatchery staffers Jimmy Sparks, left, and Drew Klingberg prepare to sex and sort Kamloops brood stock for later spawning, separating males from females as well as those females ready to spawn immediately versus those that need more time to ripen. The fish are returned to Junction Reservoir after spawning.

Person wearing blue gloves holding net with fish over metal basin with water.
The offspring from these Kamloops will be raised at CDFW’s Fish Springs Trout Hatchery and stocked by airplane as fingerlings into backcountry waters across the state approved for trout stocking.

Blue-gloved hands holding small fish over metal basin filled with water and fish.
Resplendent in their spring spawning colors, Kamloops rainbow are raised and bred for their hard-fighting ability and wild nature that allows them to thrive in California’s remote backcountry waters and provide a thrill for anglers who catch them.

Junction Reservoir in Mono County is CDFW’s brood lake for the Kamloops rainbow trout, a hard-fighting strain originally from the Kamloops region of British Columbia.

The 20-acre lake sits on a private cattle ranch off-limits to fishing. It provides a secluded setting for the brood stock, whose progeny are used almost exclusively for the aerial stocking of backcountry waters throughout the state.

“We try to keep them raised in a more wild condition so they do better in the wild,” said Hot Creek Trout Hatchery Manager Mike Escallier. “They are a really fun fish to catch. They jump a lot. They will jump 3 feet out of the water when you hook one.”

And Junction Reservoir has never looked better. This spring, the lake was filled to the brim after a long, cold, wet winter. Near the mouth of the lake’s one small inlet, Kamloops were staging for a spawning run, their feisty nature on full display in the clear waters, breaking the surface occasionally and fighting each other over territory.

Kamloops further up the inlet were blocked from moving upstream by a concrete and metal trap. That’s where CDFW’s hatchery staff collect and sort the fish each spring, spawning them manually to produce the offspring that will be deposited as fingerlings this summer by airplane into backcountry waters approved for stocking.

The entire scene is a welcome sight after California’s drought nearly collapsed CDFW’s backcountry fish-stocking program. During the darkest days of the drought, the small inlet feeding into Junction Reservoir dried up. Combined with the years-long shortage of rain and snow, Junction Reservoir withered to about half its size. In 2013, CDFW conducted an emergency fish rescue to save about 2,000 of the brood fish and its backcountry trout stocking program altogether.

The rescued fish were relocated to CDFW trout hatcheries and other nearby waters for safe-keeping. The owners of the June Lake Marina provided a major assist, offering up some of their net pens on June Lake to CDFW and its Kamloops at no charge. The June Lake net pens continue to hold some Kamloops, which CDFW spawns each spring until the program transitions back fully to Junction Reservoir and CDFW’s Fish Springs Trout Hatchery south of Big Pine where the baby Kamloops are raised.

CDFW returned brood fish to Junction Reservoir in the spring of 2017 following a wet winter and heavy snowpack. CDFW is rebuilding production toward its annual goal of collecting and fertilizing 1.4 million eggs. Some of the offspring are put back into Junction Reservoir to add genetic diversity and different age classes to the rebuilding brood population as no natural spawning occurs in the lake.

One benchmark hatchery managers and biologists are striving toward is the return of Kamloops to Crowley Lake, where more anglers will have a chance to enjoy them.

Before the drought wreaked havoc on CDFW’s Kamloops program, a portion of the Kamloops produced each year were allocated to Crowley Lake. While the backcountry trout are sterile – or “triploid” – the fish stocked into Crowley are “diploids” capable of spawning naturally.

“They spawn at different times than other strains of rainbow trout,” explained Escallier. “They give anglers fishing the creeks opportunity. They tend to be running up the creeks from Crowley right around the trout opener.”

CDFW Photos. Top Photo: The inlet to Junction Reservoir is blocked by a fish trap where CDFW hatchery employees catch fish in the spring for spawning.

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

Categories: General
  • April 29, 2019

One large spiny lobster and four smaller lobsters lined up on green mat on side of boat.

Scuba diver next to rocks and kelp underwater holding up spiny lobster and calipers.

The April 30 deadline to turn in California spiny lobster report cards is fast approaching – and CDFW needs your catch data!

The information collected from these is enormously helpful to CDFW scientists who monitor the harvest, amount of fishing effort and the gear used in the recreational fishery. Although CDFW has considerable information about the commercial lobster fishery from landing receipts and logbooks, there was very little reliable information on the magnitude of the recreational lobster catch and fishing effort prior to the launch of the lobster report card program.

CDFW first began requiring lobster fishers to fill out and turn in harvest report cards 10 years ago, in the 2008-2009 season. Persons taking or trying to take lobsters were required to possess, fill out and submit spiny lobster report cards at the end of the season.

By the 2013-2014 sport fishing season, CDFW rolled out a new spiny lobster report card system with new reporting requirements to improve the estimates of the recreational fishery harvest. The new reporting requirements included a non-return penalty fee if cards were not returned at the end of the season. Since then, card return rates have improved greatly. It could be argued that the new reporting requirements encourage more people to return their lobster report cards, which in turn has improved estimates of sport lobster catch and effort.

Results determined from report card returns after the 2017-2018 season showed a 50 percent return rate of more than 16,000 cards, compared to 22 percent (approximately 6,000 cards) after the 2008 season. In 2017-2018, more than 85,000 lobsters were reported kept versus nearly 48,000 reported in 2008. Based upon the numbers from 2017-2018, more than 171,000 lobsters were estimated taken by the recreational fishery. When added to the recorded commercial harvest for this season, recreational fishermen accounted for 31 percent of the entire California spiny lobster harvest for the season.

The cost for this year’s spiny lobster season report cards was $9.27 when purchased from CDFW offices, with a small (about 2%) surcharge applied when purchased from other vendors. Report cards are available in most places where sport fishing licenses are sold, including tackle shops and sporting goods stores, or can be purchased online. The funds raised by the sale of lobster cards are earmarked for CDFW projects, including those specifically focused on the lobster fishery.

Daily bag and possession limits are seven lobsters per person. No more than one daily bag limit may be taken or possessed by any one person unless otherwise authorized, regardless of whether they are fresh, frozen or otherwise preserved. This means that if you have a limit of seven lobsters at home, you cannot go out and get more lobsters until the first limit is disposed of in some way (eaten, given away, etc).

People often ask why commercial fishermen are allowed to use huge traps while recreational fishermen are restricted to using hoop nets. Many think this doesn’t seem fair, but CDFW is mandated by law to allow for the sustainable use of lobster by both the commercial and recreational fishing sectors. While our laws say that recreational fishermen are entitled to harvest for sport (and not subsistence use), commercial fishermen must make a living off the resource. The commercial lobster industry is highly regulated, with a fixed number of permits, and commercial fishermen are required to use traps with strict regulations concerning mesh size and escape ports that allow large numbers of sub-legal sized lobsters to come and go freely from traps. Recreational lobster fishing is considered a sport and not meant for subsistence.

CDFW would like recreational users to enjoy this resource. The number of recreational participants is not restricted, and hoop nets and diving are both very effective methods of recreational take. Finally, there are large productive areas that are closed to commercial lobster fishing but open to recreational lobster fishing, such as Santa Monica Bay, San Pedro Bay, San Diego Bay, the lee side of Catalina Island and many bays and jetties.

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Some interesting facts about these popular crustaceans: California spiny lobsters are believed to live 50 years, or more! The males have been recorded up to three feet long and weighing 26 pounds. Today, lobsters over five pounds are considered trophy-sized. For more information on spiny lobster biology, please check out our link opens in new windowCalifornia Spiny Lobster brochure (PDF).

CDFW Photos.

Media contacts:
Carrie Wilson, CDFW Communications, (831) 649-7191
Kirsten Macintyre, CDFW Communications, (916) 322-8988

Categories: General
  • February 1, 2019

Concrete fish ladder along hillside and river. Hills in background.

Blue sign with red spray-painted text reading 'house spawning'

Fish splashing in water between gate and metal examination chute.

Two people in yellow rain jackets in hatchery facility alongside fish chute filled with fish.

At Iron Gate Hatchery in Hornbrook, the fall 2018 spawning operation has just concluded. Iron Gate spawns both Fall-Run Chinook Salmon and Coho Salmon from the Klamath River. For Chinook, the hatchery staff manually collect the eggs and mix it with the milt immediately after the fish come into the facility. CDFW environmental scientists also collect heads from adipose fin clipped salmon, in order to retrieve implanted tags in the snout. The retrieved tags tell the biologists which hatchery the fish is from, and when it was released. They also collect scales, which enable them to determine the age of the fish.

For Coho Salmon, the process is a little more involved. The Coho are measured and samples taken, but the samples are sent off to a National Oceanic and Atmospheric Administration (NOAA) laboratory in Santa Cruz for analysis. While the samples are processing, the fish are kept in individually-numbered holding tubes at the hatchery. They will be spawned after the tissue analysis determines which fish are the best genetic match.

CDFW Photos

For more information about Iron Gate Hatchery, please visit: www.wildlife.ca.gov/Fishing/Hatcheries/Iron-Gate.

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

Categories: General
  • January 18, 2019

Four men and large fishing nets on small fishing boat on water. Marina and levy in background.
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.

Man wearing gray camo foul weather gear, backward ball cap, and black life vest with yellow reflectors behind helm on fishing boat on water. Cloudy skies and grass-covered levy in background
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.

Man wearing blue foul weather gear, blue ball cap, on docked fishing boat holding up two large fish. Water, land, and trees in background.
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

Categories: General
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