Science Spotlight

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  • February 7, 2019

Flocks of sea birds flying above large bay with boats, bridge, and hills in distant background
Circling birds indicate an offshore herring spawning event near Alameda.

Hundreds of sea birds floating on water with docks and homes on hills in background.
Bird activity after a spawning event.

Long, green aquatic plant material covered in thousands of tiny clear balls.
Heavy spawn on eelgrass.

On a drizzly winter day in San Francisco Bay, you might find CDFW Environmental Scientist Ryan Bartling surveying the shoreline on the research vessel Smoothhound in search of Pacific Herring (Clupea pallasii) eggs. Bartling is one member of a team of state biologists who monitor the San Francisco Bay Herring fishery in the winter months, counting eggs and using those numbers to estimate the size of the Herring population that enters the Bay each season. CDFW Environmental Scientists Tom Greiner and Andrew Weltz are the other members of the Herring Team who lead the collection of biological data and management of commercial take of Herring in San Francisco Bay.

“We see, on average, about 50,000 tons of Herring come into San Francisco Bay during the spawn events that occur about 12 times each year,” Bartling explains. “The fish typically show up from November through March, so that’s when we’re out there counting eggs and collecting biological information on adult Herring.”

Even before the spawning season starts, Bartling and Weltz, with assistance from other CDFW divers, perform SCUBA surveys in the Bay to estimate how much vegetation is present. In-season, Greiner runs weekly trawl surveys, using the 28-foot research vessel Triakis to catch adult Herring before they spawn. This catch provides information on size, weight and age of the adult herring, it also provides information on general health and condition.

Once the spawning begins, the biologists concentrate on spawn deposition surveys – which involves finding and counting egg masses wherever the fish lay them. Eelgrass (Zostera marina) and red algae (Gracilaria species) are common vegetation types for spawning Herring, but the fish will also gravitate to hard surfaces or man-made structures near the shoreline – pier pilings, boat bottoms and even submerged shopping carts, anything in the vicinity of a spawn is fair game. Although the eggs are tiny (about the size of the tip of a pencil), they’re laid in mass.

How do the biologists know where to look? There’s a dead giveaway. “The key indicators are the birds and marine mammals – they always find them first!” Bartling says. Using the circling birds as his guide, Bartling walks along the shoreline at low tide to do a visual count of eggs, or, if aboard the Smoothhound, he uses a rake to pull up vegetation from below.

When a spawning event is occurring, the actual survey time varies. CDFW scientists could be counting eggs for as little as four hours, or as long as 12 hours at a time depending on the size of the Herring school. Using the egg count numbers (which are typically in the billions or trillions), they can calculate estimates of Herring tonnage. “An estimate could be as small as one ton of Herring per spawn event up, or might be as high as 15,000 tons,” Bartling says. “It depends on time of year and the overall stock size.”

The estimates are necessary for CDFW to set quotas for California’s commercial Herring fishery, which runs from January through mid-March. Quotas are typically set at around 5 percent of the total tonnage the biologists calculated from the previous season.

CDFW Herring fishery management staff maintain a blog, link opens in new windowCDFW Pacific Herring Management News, to keep the public apprised of the health and status of the fishery. More information about the commercial Pacific Herring fishery can be found on CDFW’s website.

CDFW Photos. Top Photo: CDFW Environmental Scientist Ryan Bartling looks at herring eggs after a spawning event.

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

Categories: Wildlife Research
  • 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 24, 2019

Owl in flightShort Eared Owl. Courtesy of the National Digital Library.

Owl on snowy groundShort Eared Owl. Courtesy of the National Digital Library.

Owl perched on wooden fence post for barbed wire fence.Short Eared Owl. Courtesy of the National Digital Library.

Owl on snow-covered ground with low bush in foregroundShort Eared Owl. Courtesy of the National Digital Library.

A team of raptor biologists is working on a study of western populations of the Short-eared Owl – and are inviting members of the public to help collect and contribute important data as “citizen scientists.”

The project, known as the Western Asio Flammeus Landscape Study (WAfLS), is being conducted across eight western states, including Idaho, Montana, Nevada, Oregon, Utah, Washington and Wyoming, in addition to California. The purpose of the study is to determine the reasons for the sharp decline in Short-eared Owl populations – more than 60 percent over the last four decades across their western range.

“This project is a really unique and exciting collaborative effort to understand the species population on a very large scale,” said Carie Battistone, CDFW’s raptor biologist and WAfLS’ California State Volunteer Coordinator. “Given how wide-ranging – and in some cases, remote – the owls’ habitat is, we rely heavily on volunteers to help us collect the data we need.”

Battistone added that no special knowledge of raptors is needed in order for individuals to participate and contribute. “You don’t need to be a bird expert. You just need to have a keen interest in the outdoors and for the wildlife species that call California home,” she said.

The WAfLS project identifies 54 survey routes in California, all located within known habitat of the Short-eared Owl. “Citizen scientist” volunteers are needed to drive these routes, stop every ½ mile to look for and record owl presence and habitat features at each point. Volunteers will be asked to conduct two separate surveys on days of their choice during specified three-week survey windows in March through May. Each survey takes about 90 minutes and must be conducted during specified twilight hours, when the owls typically conduct their elaborate courtship displays.

Survey grids are located throughout much of the state from Modoc County in the north, Humboldt County in the west, Santa Barbara and Kern counties in the south and Mono County in the east. To view a map showing the grids for which volunteers are still needed, please visit the WAfLS website and click on “sign-up” on the right. The website also has a wealth of information on the project’s goals, as well as past reports, maps and volunteer resources (protocol, data sheets, etc.).

Battistone said that the information gathered by citizen scientists will be used by conservation experts and managers to design and implement strategies to help bolster populations of the Short-eared Owl.

“The project will help to determine what the Short-eared population numbers are like across the west, quantify how populations fluctuate spatially and temporally and identify how various factors – such as distribution, farming practices, grazing and climate – influence owls,” she said. “Once we have the data and resulting analyses in hand, we can make informed decisions on how to best protect and conserve the species.”

Owl photos courtesy of the National Digital Library. Top Photo: SEOW Survey: Surveying for Short-eared Owls can be a fun family activity. (CDFW Photo by Carrie Battistone.)

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

Categories: Wildlife Research
  • 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
  • December 19, 2018

Large pile of old christmas trees on dirt with live tree forest in background.

Two men wearing hats and life vests aboard small boat on body of water piled with old christmas trees. Some trees are submerged in water body. Live tree forest in background.

Boat on water body dragging small boat with two men and pile of dead christmas trees. Live tree forest in background.

Two men wearing life jackets aboard small boat on body of water with pile of dead christmas trees. Forest and mountain in background

Christmas can be the gift that keeps giving -- to anglers and fish alike.

In the north state, CDFW fish habitat technicians oversee the collection of discarded Christmas trees, which will be used to build underwater habitat structures for local waterways. Long after they’ve brightened holiday homes, these trees will provide shelter for juvenile warmwater fish species -- and ultimately will create better fishing opportunities for anglers.

According to Joseph Rightmier, a fish habitat supervisor with CDFW’s Fish Habitat Improvement Shop in Yreka, the trees are weighed down with cables and submerged, creating a refuge for juvenile fish, including Largemouth Bass and crappie.

“The fish get into the voids within the structure, which gives them some protection. And when you attract smaller fish, you also end up attracting larger, catchable fish, which hang out close to the surface and wait for a meal,” Rightmier said.

“Divers have determined that fish start congregating in and around the structures within a day or two of the habitat structures being installed. They’re hot real estate in the water!”

One of the largest efforts to collect and “upcycle” trees is conducted by Rightmier’s team in Siskiyou County. Last summer, staff used trees collected after the 2017 holidays to create and then place 22 habitat structures into Green Springs Reservoir in Modoc County. The habitat structures were comprised of approximately 200 recycled Christmas trees and small junipers. The Christmas trees were collected at drop-off locations in the cities of Alturas and Yreka, and the small junipers were harvested in the Modoc National Forest.

In 2018, Rightmier said, the Yreka fisheries habitat technicians also used trees to build fish habitat structures in three other locations: Juanita Lake, Orr Lake and Trout Lake. Similar projects have also been conducted at Lake Shastina and Dorris reservoir in the past.

Further south, CDFW’s Redding office is also overseeing a Christmas tree collection operation. The tentative collection location will be in the town of Chester, and the trees will be used for a project in Lassen County.

“Generally, we prefer hardwoods when doing habitat projects, but we do use Christmas trees when they’re available,” explained Monty Currier, an environmental scientist with CDFW’s Reservoir Program. “The trees would go a landfill to be chipped otherwise, and we believe that recycling is a better idea. And people are happy to help CDFW with this kind of habitat improvement project – who doesn’t like the idea of making our fisheries better?”

Currier is currently working with a local bass fishing group and county officials to determine a specific tree dropoff point.

Donated trees should not be flocked, and should be stripped of lights, tinsel and ornaments. The trees are usually transformed for their new use within a couple of months, before they dry out completely.

“Our fish habitat shops enjoy doing this type of project, and it makes a real difference in how successful anglers are,” Currier says. “Everybody wins – not just the fish!”

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Interested in recycling your Christmas tree in Siskiyou, Plumas or Modoc counties? Drop-off locations for Christmas trees will be located near the CDFW offices in Alturas (702 East Eighth St.) and Yreka (at the corner of Ranch and Oregon streets, due west of the CDFW yard). In Chester, the location has not yet been determined, but you can call the main office at (530) 225-2300 for information closer to the holiday.

CDFW Photos. All Photos: Fisheries biologists placing recycled Christmas trees into Mountain Meadows Reservoir, Lassen County, to create habitat for juvenile fish.

Categories: General
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