Science Spotlight

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  • 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
  • May 31, 2019

Large blue mat framed into 3 sections with black and orange rope handle on side.
A new egg mat prior to deployment (CDFW photo by Marc Beccio)

Water with orange balls floating.
Sturgeon egg mats deployed in a local waterway (CDFW photo by Marc Beccio)

Brown, dirty, rusted mat with dozes of small round eggs spread out over mat.
Egg mats with Green Sturgeon eggs (CDFW photo by Marc Beccio)

CDFW biologists have been taking a new approach to looking at reproduction in one of the oldest fish species in existence.

Green sturgeon, which are listed as threatened under the Federal Endangered Species Act, are in effect a living fossil, having swam in both the fresh and ocean waters from California to Alaska for more than 200 million years.

They are a very slow-growing fish, typically living 60 to 70 years and reaching lengths of seven feet and weights of up to 350 pounds. Little is known about where they spawn in the Central Valley and how successful they are when they spawn.

In the spring of 2017, CDFW biologists began deploying egg mats in various rivers in the Sacramento Valley. In 2018, they documented green sturgeon spawning in the Yuba River for the first time, finding approximately 270 green sturgeon eggs on an egg mat deployed immediately below Daguerre Point Dam in Yuba County.

The egg mats consist of 3.5-foot by 2.5-foot metal frames that weigh about 20 pounds and are filled with a material similar to that used for a furnace filter. Mats are deployed by being gradually lowered to the river bottom from the bow of a boat. They are then retrieved by slowly hauling in the float line to avoid dislodging eggs stuck on the mat.

Unlike salmon and trout which dig redds and cover their eggs with gravel, green sturgeon females “broadcast” (release) their eggs into the water, which then sink to the river bottom, where their sticky surfaces adhere to various objects. Of eight egg mats deployed in the pool below Daguerre Point Dam, the biologists collected 270 eggs from just a single mat. As spawning locations can be difficult to identify, and eggs can be distributed broadly by the current within individual locations, documenting this spawning event was important.

A subsample of 33 eggs was retained to determine the developmental stage which will be used to calculate a spawning date. The mat was then lowered back to the river bottom. The 33 eggs collected represent about 0.02 percent of the total produced by a female green sturgeon of average size.

After confirming the presence of adult green sturgeon in the Yuba River, CDFW biologists believe the river may be important habitat for the species. Further research using these egg mats over the next several years will help fisheries managers identify critical spawning locations and habitat requirements for the future protection and enhancement of the species.

CDFW Photos. Top Photo: Green Sturgeon underwater. CDFW photo by Mike Healey.

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Media Contact:
Kyle Orr, CDFW Communications, (916) 322-8958

Categories: Wildlife Research
  • May 9, 2019

Closeup of man holding up fishLahontan cutthroat trout are a Crowley prize. In addition to natural spawning that occurs in the lake, CDFW plants the fish as fingerlings in the fall. By the spring opener, many like this fish are resplendent in their spawning colors.

Man in brown and beige CDFW uniform on boat bent over cooler with fish while holding a ruler in cooler. Jim Erdman conducts creel surveys to see how many trout CDFW planted last fall turn up on opening day. Fish 15 inches or longer are determined to be from last fall's stocking when they were planted as fingerlings.

Man in white t shirt, sunglasses and ball cap on beach in front of body of water holding up a fish with spots. Mark Risco from Temecula shows off the 20-inch brown trout he caught opening day at Crowley Lake. In addition to natural spawning, CDFW's Hot Creek Hatchery stocks thousands of brown trout each year, which are very popular with Crowley anglers.

Man wearing CDFW uniform, sunglasses, and green ball cap standing in dirt parking lot holding clipboard.CDFW volunteer Carl Ronk conducted opening day creel surveys at Crowley Lake along with CDFW Environmental Scientist Jim Erdman.

Mono County’s Crowley Lake is a destination fishery that attracts trout anglers of all kinds – bait fishermen, lure casters, trollers and fly anglers – throughout the state during its open season.

The sprawling lake, situated at 6,700 feet and covering some 5,300 surface acres in the Eastern Sierra, also represents a huge investment for CDFW. The nearby Hot Creek Trout Hatchery raises hundreds of thousands of rainbow, brown and Lahontan cutthroat trout for Crowley each year that provide the backbone of the quality angling experience. Many of the fish are stocked as fingerlings in the late summer or fall and grow rapidly in the invertebrate-rich environment. Some go on to spawn in the lake’s many feeder creeks and supply wild progeny to the population.

All of which helps explain why CDFW Environmental Scientist Jim Erdman has been out conducting creel surveys at Crowley every opening day since joining CDFW in 2005. Based in Bishop, Erdman’s goal is to contact at least 300 anglers and see which hatchery fish are turning up in their catch, in what numbers, in what proportion of species, and in what condition. The report is an annual check to see whether CDFW’s management plan for Crowley remains on point or whether adjustments need to be considered. The opening day creel surveys have been taking place since 1997 when CDFW biologist Curtis Milliron wrote the Crowley Lake Management Plan.

CDFW volunteer Carl Ronk assisted Erdman this past opener April 27. The two split up at times – one checking anglers along the shoreline, the other awaiting returning boats to the Crowley Lake Fish Camp marina, the only formal boat launch at the lake.

Their tools for the day included a clipboard for note-taking and a 15-inch wooden “Crowley Stick” for measuring fish. CDFW biologists have determined that a fingerling trout stocked in the fall should be 15 inches or greater by opening day in the nutrient-rich waters. Erdman typically completes and submits his report by the afternoon of the opener and shares it with anyone interested. Local papers have been known to reprint it in its entirety.

For the 2019 Crowley opener, the creel survey found shoreline angler success was greatly improved from the previous year with an average catch per angler of 3.66 trout compared to last year’s average of just 0.71 trout. Overall, however, catch rates and total catch per angler were lower than 2018. Fish size was also down. Approximately 41.4 percent of the rainbow trout measured were greater than 15 inches, well below the annual average of around 70 percent. The catch rate fell below CDFW’s management goal of one fish per angler for each hour of effort.

A long, cold winter and late ice-out were cited as factors in a slower-than usual Crowley opener and smaller fish with less time to fatten up post ice-out.

“Crowley Lake did not ice-out until April 10, 2019, and this kept fish in deeper water than usual,” Erdman wrote. “No fish were seen in the McGee, Crooked or Whiskey Creek inlets and few to no fish were seen staging for a spawning run. Water temperatures in the inlets remained below 40 degrees.”

Rainbow trout made up the majority of the catch followed by brown trout. Lahontan cutthroats were scarce. CDFW annually stocks 100,000 Lahontan cutthroat fingerlings in the fall. Cutthroats represented just 0.9 percent of the shoreline catch and 1.6 percent of the boating catch compared to 2018 findings of 11.3 percent of the shoreline catch and 2.2 percent of the boating catch.

Opening day on Crowley Lake, with its big crowds and festive atmosphere, has always been about more than bag limits as reflected in Erdman’s creel survey report.

“Returning boat anglers were a bit slower than usual coming in off the lake probably due to the pleasant conditions on the lake. Relaxing in the sun and drifting in the slight breeze. A grand day to be on the water.”

CDFW Photos. Top Photo: CDFW's creel surveys play an important role in evaluating the lake's management and stocking allocations.

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

 

Categories: Wildlife Research
  • 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
  • April 19, 2019

Brown vials with green tops in a dark gray tray.

Man wearing white lab coat holding up two sheets of white paper with graphs.

You've seen television forensic dramas where sleuths use science to help find a killer. What many don’t know is these same types of similar techniques like fingerprinting can help investigators track down the source of an oil spill. The California Department of Fish and Wildlife’s Petroleum Chemistry Laboratory (PCL), located east of Sacramento in Rancho Cordova, is tasked with determining the origin of oil spills, which can lead to criminal charges in California. They do this by comparing the chemical properties of the oil to known sources from around the world. The end result is sound scientific evidence that can hold up in a court of law.

Media Contact: Steve Gonzalez, CDFW OSPR, (916) 322-1683

Categories: Wildlife Research
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