Science Spotlight

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  • April 2, 2019

The latest issue of California Fish and Game, Vol. 105, Issue 1 (PDF), focuses on marine species, bringing new insights and understanding of several fish species found off the California coast.

In A very long term tag recovery of a California scorpionfish (Scorpaena guttata) (PDF), Roberts and Hanan report the remarkable recovery of a tagged scorpionfish that had been at liberty far longer than any previously recaptured scorpionfish. The recovery was made during a four-year mark-recapture study on nearshore groundfish off southern and central California. More than 32,000 fish were recaptured, with an average of 408.8 days at liberty. The study results indicate that scorpionfish demonstrate strong site fidelity, given that a majority of the fish were recaptured within 5k of their original tagging site. The scorpionfish that is the subject of the article was tagged in 2004. It had been at liberty for nearly 14 years (5,048 days). After removing the tag, the fisherman who captured the fish reported that he released it “unharmed and looking very healthy.”

Another paper reports on a method for estimating the age of roosterfish using dorsal fin spines (PDF). According to authors Chavez-Arellano et. al, the roosterfish is considered a prized species by the sport fishing community and provides a significant economic benefit to the Mexican tourism industry. However, little is known about its biology, ecology, and movement patterns. The authors embarked upon a study to assess which sections of roosterfish dorsal fin spines have the most legible indicators of growth for use in future aging studies. Their work provides the initial basis from which future aging studies can be conducted.

Finally,Primary and secondary nursery areas for leopard and brown smoothhound sharks in San Francisco Bay, California (PDF), summarizes a 31-year study to determine primary and secondary nursery habitats for leopard and brown smoothhound sharks within South San Francisco Bay, adding new knowledge to the biology of both species.

As it has for the past 105 years, California Fish and Game continues to publish high-quality, peer-reviewed science that contributes to the understanding and conservation of California’s wildlife. We look forward to witnessing the contributions of the next installment.

CDFW Photo.
Media Contact:
Lorna Bernard, CDFW Communications, (916) 322-8911  

Categories: California Fish and Game Journal
  • March 20, 2019

Side of boat with two men wearing white hard hats leaning over the railing reaching for large black and green machine held up by a crane.
The ROV Beagle (CDFW photo)

Orange fish with very few white dots in dorsal region underwater next to large pinkish red sea plant
Starry Rockfish from the Channel Islands (CDFW photo)

Red and orange fish with spiny dorsal fin underwater. Red fish in background.
Yelloweye and Vermilion rockfishes from the North Coast (CDFW photo)

Orange fish with white stripes across head and down body underwater.
Canary Rockfish from the North Coast (CDFW photo)

Gray speckled fish underwater on top of rock covered in round white anemone
Lingcod, white-plumed anemones, female kelp greenling (CDFW photo)

Orange fish with thick white bands and spiny dorsal fin underwater over large rock covered in salmon pink creature with narrow, long spiraling limbs.
Quillback Rockfish and Basket Stars from the North Coast (CDFW photo)

Orange-pink creature shaped like a ball underwater with hundreds of long hair-thin extensions extended toward rock.
Benthic siphophores use threads to walk and anchor to the seafloor (CDFW photo)

Black and green machine with two yellow tanks on top above water, suspended by chain.
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 link opens in new windowCDFW'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)


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

Categories: Wildlife Research
  • September 19, 2018

Green sea turtle on top of blue tarp secured by poles in shallow water
Ready for release.

Green sea turtle in shallow water shoreline heading out into open water. People with surf boards standing in water in background.
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.

Categories: General
  • April 5, 2018

The latest issue of California Fish and Game, the California Department of Fish and Wildlife’s scientific journal, is now available online! Issue 103(4) features articles that add to the knowledge base for three marine species, all of which face potential threats from overharvesting, incidental take and loss of habitat: Thorny stingray, Chinook salmon and green abalone. 

The link opens in new windowThorny stingray (Urotrygon rogersi) (PDF) is common in the eastern Pacific, from the Gulf of California south to Ecuador, and is frequently a by-catch of commercial shrimp trawlers. Little is known about its life history and movements. It was thought to occupy relatively shallow depths ranging from two to 15 meters, with a maximum recorded depth of 30 meters. In their published research, Acevedo-Cervantes et al. report the discovery of specimens at a depth of 235 meters—an indicator that the Thorny stingray has the capacity to survive beneath the disturbance of commercial shrimping activity. According to the authors, this new information is “of vital relevance” for the management of the species.

Adams et al. examined the effects of link opens in new windowEl Niño on adult Chinook salmon as they migrate through the Gulf of the Farallones (PDF). Researchers found that the dressed weight of commercial landed Chinook was lower during El Niño compared to non-El Niño years, a reduction attributed to a disruption in the normal feeding cycle in the Gulf of the Farallones. The analysis suggests that management agencies need to give more consideration to ocean conditions as risk factors in planning the recovery of endangered and at-risk Chinook salmon spawning runs.

link opens in new windowGreen abalone (Haliotis fulgens; Philippi) (PDF) were once part of a large recreational and commercial fishery, but are now estimated to be at less than 1% of their baseline density. Past attempts at restocking wild populations using juvenile farm-raised green abalone have resulted in high mortality rates. In “Outplanting large adult green abalone (Haliotis fulgens) as a strategy for population restoration,” author Caruso explores the efficacy of using adult specimens—at least 10 years old—to augment wild populations. The resulting 40 percent survival rate is much higher than the survival rates of previous projects that used juveniles. Although it is costly to raise green abalone to adult size, it may be the best method, given the decades of past unsuccessful restocking attempts.

These articles provide information useful to fisheries managers and should be helpful for future recovery efforts.

Cover photo © Peter Hemming

Categories: California Fish and Game Journal
  • September 14, 2017

brownish bull kelp lying on a tan beach
aerial infrared photo of kelp forest off a small part of California coast

Beneath the waters off the California coast are vast forests that are home to an astounding variety of animals. Their sunlit canopies can soar 150 feet from the ocean’s floor. But instead of trees, these forests are made of kelp.

Worldwide, kelp is used in a host of everyday products like toothpaste, pudding, ice cream and even pharmaceuticals. Although kelp is valuable to humans, it is critical to sustaining life for many ocean-dwelling wildlife species ranging from microscopic plankton to sea otters, pelagic birds and predatory fishes. When a kelp forest is depleted, the entire underwater ecosystem can be thrown out of balance. This is why CDFW scientists are tracking and studying the amount of kelp growing in coastal waters.

In 1989, CDFW marine biologists began using aerial surveys to monitor the size of the kelp forests off of California’s coast. A second survey was conducted a decade later, and since 2002, CDFW has made an effort to conduct these surveys annually (although budget issues sometimes require skipping a year).

The surveys are conducted along the entire coastline and offshore of the Channel Islands. CDFW conducted the earliest surveys on its own, but now contracts out for this work. The contractor uses an aircraft with a specialized camera system that picks up the infrared image of the kelp. Those images become Geographic Information System (GIS) shapefiles that capture a snapshot of what the kelp canopy looks like on a given day. The images enable the viewer to see and compare the spatial area of a specific kelp forest over time.

A graph depicting CDFW’s historic aerial kelp survey data is located on the Kelp and Other Marine Algae webpage.

CDFW’s most recent (2016) kelp survey includes the following findings:

  • The south coast mainland and the Channel Islands both experienced a reduction in kelp when compared to 2015 levels. The south coast mainland had almost half the canopy level surveyed the previous year.
  • Along the central coast, kelp canopy levels were almost double that seen the previous year.
  • North central canopy levels, while still low, were just over five times the 2015 survey levels.
  • The north coast canopy levels were just over twice the 2015 measured canopy levels – but are still below the normal range for this area.

Rebecca Flores Miller, a marine environmental scientist with CDFW’s Marine Region office in Monterey, was the coordinator for the 2016 kelp survey.

“Kelp does fluctuate normally, anyway … there is a seasonality with it,” she explains. “However, during El Nino and warm water conditions as we’ve had in the recent past, the canopy doesn’t grow as well.”

Coastal development can also negatively affect the kelp canopy, as it sometimes leads to pollution, increased turbidity (which reduces the light needed for photosynthesis) and siltation (which can hinder growth or bury young kelp). An increase in urchin populations can also have a dramatic impact on kelp, and recently, a wasting disease decreased the numbers of sea stars (a predator of urchins) statewide.

“All of these things are connected within the ecosystem,” Flores Miller says.

Kelp survey data is available to anyone who is interested – members of the general public, other governmental agencies, universities and researchers.

The dataset has many uses, both within and outside of CDFW. It is used during the review process for commercial kelp bed lease requests. It has been a critical piece of the Marine Protected Area planning process. It has been used to help predict the abundance of many kelp forest-dependent species valued by humans, such as abalone. And it has helped scientists understand issues such as the recent abalone die-off in northern California.

CDFW Photos: giant kelp and bull kelp (by Rebecca Flores Miller), and image of kelp forest near Cambria taken during the 2016 aerial kelp survey.

Categories: General