Science Spotlight

CDFW staff with tanker truck used to transport smolts


The Salty Lady sportfishing boat hosted Richmond youth


Smolts being released into Richmond Harbor






Fall-run Chinook salmon smolt

Moments after the sun set on Richmond Harbor’s Brickyard Cove on June 19, CDFW and its partners released approximately 200,000 hatchery raised juvenile fall-run Chinook salmon (known as smolts) into the bay.

The release was part of a larger effort to truck approximately 19.7 million fall-run Chinook salmon to locations in the San Francisco Bay, San Pablo Bay and lower portions of the Sacramento-San Joaquin Delta. CDFW has two more smolt releases planned for the week of June 20. Since beginning the effort in mid-April, staff have completed three to six releases per week.

Sunday night’s release was a collaboration with the City of Richmond, Golden State Salmon Association and Richmond Police Athletic League. The team invited a group of young people from Richmond to watch the release from a 56-foot sportfishing boat called The Salty Lady, the use of which was donated for the event to offer youth a glimpse into fishery operations.

“These kids definitely got a unique opportunity and a front row seat to watch this release,” said Senior Environmental Scientist Jason Julienne, supervisor over CDFW’s North Central Region hatcheries. “I hope it gets them interested and excited for fish and fishing, with the hopes of catching one of these fish when they return as adults in a few years.”

The goal of the releases is to improve survival of the salmon smolts by helping them bypass 50 to100 miles of hazardous river conditions caused by three consecutive years of drought in the Central Valley. CDFW fisheries biologists tracked flows and water temperatures in the fish's usual migration corridors and recognized that survival would be a challenge without intervention.

“We want to help ensure some of these fish survive to contribute to commercial and recreations fisheries, as well as hatchery and natural area production in the coming years,” said Julienne.

The smolts, raised at CDFW’s Feather River Fish Hatchery in Oroville, were eight to 10 months old when released. At that age, the smolts are developmentally ready to handle the salinity of bay waters. The Brickyard Cove location in Richmond was chosen because of its favorable tides and proximity to deep waters.

“We try to use outgoing tidal movements and the cover of darkness to help get these fish oriented in the right direction toward the Pacific Ocean, and reduce predation,” said Julienne.

All fish from yesterday’s release were marked and implanted with coded wire tags so CDFW can track their returns and determine how they contribute to fisheries and production in coming years.

For more information read CDFW’s news release on the trucking operation.

A long, wet winter has been good for Junction Reservoir and CDFW’s Kamloops rainbow trout that live there.


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.


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.


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.


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

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

Working late, Mojave River hatchery staff apply FDA-certified epoxy coating to hatchery rearing ponds.


CDFW fish transportation truck at Fillmore Hatchery


Acting Mojave River Hatchery Manager Forest Williams at work


A hatchery crew releases trout into the Feather River


A fishy view of trout planting on the Feather River

The beginning of trout fishing season in Southern California is just around the corner, and CDFW biologists and hatchery staff are striving to maximize hatchery trout availability for the many anglers who will cast lines in coming weeks. Trout angling in lower-elevation waters of Southern California generally begins in November and continues through April, to correspond with colder water temperatures that can sustain stocked trout.

Precise temperatures are just one of the criteria that must be met before trout stocking begins. Currently, these conditions are approaching optimal levels, but CDFW is running about two weeks behind schedule due to unforeseen circumstances at Mojave River and Fillmore trout hatcheries, two of CDFW’s southernmost facilities.

The Mojave River Hatchery, built in 1947, raises and stocks a ten-year average of 340,000 pounds of catchable trout per year. Beginning in June of this year, extensive maintenance and facility upgrades necessitated turning off the water for a six-month period. While the completed upgrades will ultimately result in better and more efficient trout production for Southern California, the project ran about two months behind schedule. Water is scheduled to flow again at Mojave River Hatchery in late November and the hatchery will be populated with fingerling trout for fast growth. Mojave’s year-round water temperatures yield fast trout growth resulting in maximized yield in minimal time.

While the Mojave River Hatchery was closed, Fillmore Hatchery, built in 1941 on the Santa Clara River, experienced a significant loss of trout inventory intended for Southern California angling due to gas bubble disease. Gas bubble disease is a result of supersaturated gasses (oxygen, nitrogen and carbon dioxide) present in well water pumped from a deep aquifer. While Fillmore Hatchery is equipped to aerate this water and make it suitable for trout, an unknown variable (possibly a drought-depleted and then recharged aquifer) overwhelmed that ability. In an average year, Fillmore Hatchery produces about 400,000 trout for lakes and streams in Southern California. To reduce fish losses from gas bubble disease in the last several weeks, catchable fish were stocked from Fillmore to appropriate waters, and some fish were transferred to other hatcheries. Ultimately, the gas bubble disease at Fillmore resulted in a loss of about 50 percent of inventory. While emergency measures taken by Fillmore staff and

CDFW fish pathologists resulted in better conditions and lower gas super-saturation, the hatchery must be depopulated so that the issue can be addressed entirely. As soon as all trout are removed, hatchery staff and scientists will increase the gas diffusion capability of aeration towers at Fillmore, in order to handle supersaturated well water for the short and long term.

The status of these two hatcheries presented a substantial problem for trout stocking in Southern California that was solved in part by hatcheries in Central and Northern California. These hatcheries have sufficient catchable size trout to supply Southern California’s approved waters immediately and in coming weeks. Thanks to strategic planning and trout production at a statewide level, Northern and Central California can supply fish to Southern California without impacting originally scheduled trout releases in their respective areas.

Trout stocking for Southern California waters will begin this week and hatchery trucks are on the move. Hatchery staff will work quickly to distribute trout to as many approved waters as possible. Trout stocking to Southern California will initially be lighter than usual, but will likely pick back up in 2018. As Mojave River Hatchery comes back online, fish transferred to that facility will be fed and reared to maximize daily growth. We anticipate another large batch of catchable trout available for Southern California toward early spring 2018.

Hatchery staff will be doing everything possible, statewide, to maximize trout production and releases to approved waters in the coming months. Staff work diligently for the angling public and appreciate their continued support.

The statewide planting schedule is updated in real time online.

CDFW photos. Top: Steelhead trout at Mokelumne River Hatchery

For more than a century, CDFW’s Trout Hatchery and Stocking Program has been providing recreational fishing opportunities to anglers throughout California. Today, the trout hatchery program is composed of 13 hatcheries, which oversee 20 distinct fish production programs to produce 17 strains, species and subspecies of trout.

McCloud River Redband Trout (Oncorhynchus mykiss stonei) is the latest addition to the CDFW’s production and release efforts. McCloud River Redband Trout is a unique sub-species of rainbow trout endemic to the upper McCloud River area of Shasta and Siskiyou counties of northern California. This fish has beautiful coloration and unique adult characteristics – a pronounced crimson lateral stripe, adult parr marks, relatively large black dorsal spotting, yellow-white hues on the underbelly and white-tipped fins.

The new production and stocking program for McCloud River Redband Trout at Mt. Shasta Fish Hatchery will focus on the upper McCloud River, including McCloud Reservoir. Given that stocking will occur solely within the historic watershed of McCloud River Redband Trout, the program is distinguished by CDFW as a Heritage Trout Production Program. A Heritage Trout is defined as a species of trout native to California, in its native habitat and area. This type of fishery represents the most natural form of aquatic habitat, species and angling opportunity available. Many anglers seeking additional challenges and goals will specifically pursue heritage trout fisheries.

While modern genetics management and conservation hatchery methods are utilized in the McCloud River Redband program, the hatchery-produced fish are primarily for recreational angling and not for release to areas containing wild and genetically pure McCloud River Redband Trout in their natural habitat. This ensures that the most wild populations remain in their native habitat and can continue local adaptation without hatchery influence. CDFW expects the McCloud River Redband Trout program to reach full implementation by 2019-20. The McCloud River Redband program demonstrates CDFW’s progress and commitment to conservation efforts and fisheries management.

CDFW trout hatcheries will continue to produce and stock several strains and species of trout statewide to promote trout angling opportunities, and contribute to the conservation of California’s native species and sub-species of trout. One of the next priorities for the department’s trout hatchery program will commence in 2018, and focus on advancing the Kern River Rainbow Trout program at CDFWs’ Kern River Planting Base.

CDFW Fish and Wildlife Technician Beau Jones stocking McCloud River Redband Trout in August 2017. CDFW photos by hatchery staff.