Science Spotlight

Lahontan 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.

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.

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.

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
 

The ROV Beagle (CDFW photo)

Starry Rockfish from the Channel Islands (CDFW photo)

Yelloweye and Vermilion rockfishes from the North Coast (CDFW photo)

Canary Rockfish from the North Coast (CDFW photo)

Lingcod, white-plumed anemones, female kelp greenling (CDFW photo)

Quillback Rockfish and Basket Stars from the North Coast (CDFW photo)

Benthic siphophores use threads to walk and anchor to the seafloor (CDFW photo)

ROV Beagle (CDFW photo by Michael Prall)

Marine scientists from the California Department of Fish and Wildlife (CDFW) and Marine Applied Research and Exploration (MARE) recently completed an unprecedented three-year survey of deep-water habitats off the California coast using a remotely operated vehicle (ROV). Beginning in 2014, MARE’s ROV Beagle was deployed throughout the state to survey and record the species and types of habitats associated with marine protected areas (MPAs) and nearby, comparable rocky habitats.

Surveys were video-based and provided a first look at the many recently established MPAs throughout the state and generated much needed data on abundance and distribution of fish species harvested from rocky habitats.

According to Marine Environmental Scientist Mike Prall, “Many of the areas visited by the ROV Beagle during the surveys had probably never been directly observed by human eyes before our surveys. And all data gathered from video and still imagery collected during the expeditions have provided much needed information about California’s vast deep-water habitats.”

This statewide survey was funded by a $1.9 million research grant awarded to CDFW in 2013 to survey underwater habitats from Mexico to the Oregon border using state-of-the-art underwater technology operated by MARE. In all, five deployments visited over 130 locations and collected hundreds of hours of video in standard and high definition formats, as well as over 50,000 digital still photographs.

Working through MARE’s video processing laboratory in Eureka, trained technicians methodically characterized habitat and identified hundreds of species of fish and invertebrates from high definition video and still photography. Detailed information was also collected from the ROV’s path across the seafloor, which was then used to accurately identify the location of each observation. CDFW scientists used that data for future analysis of abundance, size estimates and patterns of distribution for important species, among other applications.

Preliminary examination of observations from the first ROV deployments have already uncovered interesting findings about species and habitats. In Southern California, small reef patches surrounded by soft sediments showed a high abundance of rockfish in many locations. These habitats are sparsely scattered throughout Southern California’s nearshore waters and may be important to overall fish abundance in areas lacking prominent rocky reefs.

Not surprisingly, the northern California surveys uncovered different findings from those in southern California. Rocky reefs in northern California had patchy distributions of fish, with some areas surprisingly devoid of common species. Strong ocean currents, large waves, and increased sedimentation from rivers created complex dynamics on the north coast and may have influenced the patchy distribution. One striking observation throughout all areas visited statewide was the high abundance of the predatory lingcod.

“Participating in this survey has been a high point of my career at CDFW,” Prall said. “As we continue to work with the massive amount of data gathered, I am excited to see what new results emerge and to see how this work will inform our understanding of California’s amazing underwater resources.”

CDFW scientists and MARE have been collaborating and have explored underwater habitats together throughout California waters since 2003 and have developed highly refined ROV survey methods and processing techniques. Since completion of this endeavor in 2016, this project has provided the most comprehensive and most thorough visual survey of California’s deep water rocky habitats ever attempted.

Information gathered from the data will provide insights into how species may be benefiting from protections afforded by MPAs and give resource managers greater knowledge of managed marine species. CDFW and MARE are currently partnering to survey warty sea cucumber populations in and around Anacapa Island State Marine Reserve. Two deployments funded by the Resources Legacy Fund were completed in 2018. Thanks to this work, scientists now better understand the biology of this important harvested invertebrate species, and in addition, the role of MPAs in the sustainability of the fishery.

Photos taken from the ROV Beagle during the project surveys can be seen on CDFW's Flickr site. For more information about marine protected area monitoring efforts, visit the CDFW website.

Top photo: The ROV Beagle (CDFW photo by Michael Prall)

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Media contact:
Carrie Wilson, CDFW Communications, (831) 649-7191

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

Habitat is the key to the long-term survival of Sacramento River winter-run Chinook in California. Since 1999, CDFW has been working with multiple agencies and private parties on planning efforts to restore the population of these endangered salmon. More than $100 million has been allocated to specific habitat restoration work on Battle Creek, which comprises approximately 48 miles of prime salmon and steelhead habitat.

Over the next two months, approximately 200,000 juvenile winter-run Chinook will be released into the North Fork of Battle Creek. The introduction of these fish, which were spawned from adults last summer, is occurring sooner than expected due the availability of fish from the Livingston Stone National Fish Hatchery Winter-run Chinook Captive Broodstock Program. The fish were raised at Coleman National Fish Hatchery and are being released by Coleman Hatchery personnel. These additional fish could help bolster the winter-run Chinook population and be a potential catalyst in their recovery.

CDFW Senior Environmental Scientist Doug Killam has worked on the Battle Creek Reintroduction Plan for nearly a decade and has been instrumental in moving in-stream projects forward. Killam sees the release of 200,000 smolts as an important step in the overall effort. The release will reestablish winter-run Chinook in a new drainage and create a separate new population. Currently there is only one viable population existing in the Sacramento River directly below Keswick and Shasta Dams. The recent drought affected the volume of the critical cold-water pool in Shasta Lake and the release of warmer water in the drought years of 2014 and 2015 resulted in major losses to eggs and young salmon below the dam. Biologists have long recognized that having more than one winter-run Chinook population is imperative for the long-term survival of the species.

A volcanic region with rugged canyons and dramatic scenery, the North Fork of Battle Creek is unique since it has both cold snowmelt water and large amounts of spring water flowing into it at critical times for winter-run salmon to hold over in and spawn in. It is also one of a handful of waters that can support all four of the Chinook salmon runs that return to the Sacramento River Basin. Hydroelectric development of the creek in the early 1900s largely eliminated winter-run Chinook and other salmonid runs from swimming far upstream to access the cooler water required for these unique summer spawning salmon. Recent efforts to bring the fish back to the North Fork include dam removals, rock fall removal, new fish ladders and fish screens and – most importantly – an agreement to increase stream flows to provide fish with the water quantity and quality they need to survive and thrive in this important keystone stream.

CDFW photo by Heather McIntire. Map by CDFW Fisheries Branch.