Science Spotlight

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  • January 5, 2021

The link opens in new windowCalifornia Fish and Wildlife Journal concludes the 2020 Special Issue installments with the winter quarter’s Special Wildland Fire Issue. With this year’s unprecedented fire season, and California’s fire-adapted natural communities taking center stage in land management discussions throughout the State and beyond, this issue is especially poignant as we reflect on this past year and contemplate the incoming new year.

Unlike previous Special Issues, this issue is divided into three sections: Vegetation Treatment and Policy, Fire Impacts on Plants, and Fire Impacts on Wildlife and Water. Each section highlights a piece of the wildfire and landscape management ‘puzzle’ through an examination of fire and its impacts on California’s fire-adapted ecological landscape.

One of these unique communities, the Pine Hill Ecological Reserve in El Dorado County, is home to almost 750 plant species, some of which can only be found at Pine Hill due to its unique soil composition. Researchers from CDFW, the California Native Plant Society and Sacramento City College investigate the impacts of different fuel-reduction methods on Pine Hill Ceanothus in link opens in new window“Effects of a firebreak on plants and wildlife at Pine Hill, a biodiversity hotspot, El Dorado County, California” (PDF). The article examines the effects of hand clearing and pile burning on chaparral species within the Wildland Urban Interface and the secondary impacts on wildlife. The study also includes the exciting discovery of new seedlings of Pine Hill Flannelbush, the rarest and most endangered plant in El Dorado county, and a fire-obligate germinator!

Plants that depend on fire to propagate aren’t the only plant communities impacted by the long-term fire suppression practiced in the western United States. New and updated technology is helping landscape managers and scientists study and assess the pre- and post-fire impacts to landscapes using remote sensing and modeling techniques. This type of data collection and analysis helps inform scientists and policy makers on landscape and watershed-level scales and helps focus efforts to manage habitats and sensitive plant communities before and after wildfires. One such effort is presented by Sonoma County scientists in link opens in new window“Sonoma County Complex Fires of 2017: Remote sensing data and modeling to support ecosystem and community resiliency” (PDF). With the help of NASA and other experts the team evaluates the impacts of the 2017 fires to woody vegetation within areas that burned during wind-driven and non-wind driven events to evaluate canopy condition. Using lidar data, the team identifies important predictors for post-fire woody canopy condition, which highlights the importance of high-resolution airborne mapping technology for informing management decisions.

Management decisions include when and how to monitor pre- and post-fire events, and the CSU Monterey Bay’s study link opens in new window“Analysis of the impacts of the Soberanes Wildlife on stream ecosystems” (PDF) highlights the need for monitoring wildfire’s impacts on coastal streams and benthic macroinvertebrate responses to fire events. This monitoring is especially important because macroinvertebrates are the foundation for in-stream salmon and steelhead foodwebs, and the ability of these microscopic organisms to recover from wildfire also impacts the recovery of these keystone species in California’s rivers and streams.

This quarter’s Special Wildlife Fire Issue also includes examinations of impacts and responses of Roosevelt Elk forage in Humboldt County, an essay on the California Vegetation Treatment Program, amphibian responses to wildfire and other topics that span California’s rich ecological diversity.

The California Fish and Wildlife scientific journal has published high-quality, peer-reviewed science that contributes to the understanding and conservation of California’s wildlife for more than 100 years. We look forward to the continued contributions in the next decade to come.

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Media Contact:
Kirsten Macintyre, CDFW Communications, (916) 804-1714

Categories: California Fish and Game Journal, Science Spotlight
  • December 14, 2020
Kokanee salmon

CDFW biologists and hatchery staff overcame several obstacles for a successful 2020 kokanee salmon egg collection effort on the Little Truckee River.

scientist sitting with several buckets ready to fill with fertilized salmon eggs collected from the river
Kokanee salmon eggs are collected and fertilized streamside, as shown in this 2019 photo, before being taken to a CDFW hatchery for incubation.

Several scientist standing in shallow part of the river with weir nets to block salmon to collect eggs to raise at the hatchery
A temporary weir is set up along the Little Truckee River to block, catch and spawn kokanee salmon that have migrated up from Stampede Reservoir as shown in this 2019 photo. Among other challenges in 2020, CDFW staff had to conduct the annual kokanee spawn without the help of volunteers due to COVID-19-related precautions.

In spite of challenges presented by wildfires, forest closures, unhealthy air quality and the COVID-19 pandemic, CDFW staff from the American River Trout Hatchery and Fisheries Branch nonetheless conducted four successful kokanee salmon egg collections on the Little Truckee River this fall.

Slightly more than 1.3 million eggs were collected from kokanee salmon migrating from Stampede Reservoir in Nevada County into the Little Truckee River to spawn. Stampede Reservoir’s kokanee salmon serve as CDFW’s broodstock for the popular State fishery.

CDFW typically relies on volunteers from the public and angling groups to help with the annual egg collection effort – but that extra manpower was unavailable this year due to COVID-19 precautions.

“This year was unique to say the least, but this was a high priority for us,” said Jason Julienne, senior environmental scientist supervisor for CDFW’s North Central Region hatcheries. “Many of the waters that support the kokanee fishery are not self-sustaining, and depend on annual releases to provide ample opportunity for anglers.”

Due to COVID-19 concerns, this year’s egg collection involved less staff than normal, which slowed the process a bit. Typically, the team can collect all the eggs needed to support the program in two to three days. This year, it took four days, and required extensive coordination with the U.S. Forest Service in order to get special access to closed areas of the Tahoe National Forest.

“Luckily, everything came together on time and we were able to get it done,” Julienne said. “We had 12 to 15 staff participating in each of the four egg collections, as well as two staffers who remained onsite for five weeks to maintain the fish barrier weir and monitor salmon numbers coming up the river.”

The collected eggs are now being incubated at CDFW’s San Joaquin Hatchery and American River Trout Hatchery. Once the fry reach about three inches in size, they will be stocked to support recreational fishing at 15 lakes and reservoirs throughout the state. About 850,000 kokanee fry are released annually.

Kokanee salmon (Oncorhynchus nerka) are the landlocked version of Sockeye salmon native to Alaska and the Pacific Northwest. Instead of migrating to the ocean, adult kokanee inhabit large lakes and impoundments before returning to their natal streams or using gravel shorelines to spawn. Like all Pacific salmon, kokanee die after spawning, their whole life cycle spanning two to four years.

Although they only average about 12 inches in size as adults, kokanee salmon are an exceptionally popular sport fish noted for their excellent table fare. As the kokanee fishery has thrived, bag and possession limits have been increased at several lakes and reservoirs in recent years, including at Lake Pardee in Amador County, New Bullard’s Bar Reservoir in Yuba County and Trinity Lake in Trinity County.

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Media Contact:
Peter Tira, CDFW Communications, (916) 215-3858

CDFW Photos

Categories: Science Spotlight
  • November 4, 2020

The link opens in new windowfall 2020 issue of California Fish and Wildlife (PDF), CDFW’s quarterly scientific journal, features a series of scientific articles on the environmental impacts associated with legal and unpermitted commercial cannabis cultivation. Once primarily hidden deep in the forests of the Emerald Triangle, cannabis cultivation activities are now occurring all over California.

Like other forms of commercial agriculture, land use practices associated with cannabis agriculture can pose a serious risk to many threatened and endangered species. Elijah Portugal and Jason Hwan, CDFW scientists, explore the environmental impacts with an article titled link opens in new window“Applied Science to Inform Management Efforts for Cannabis Cultivation, Humboldt County, California” (PDF). The piece focuses on the preliminary findings of a study examining the impacts of cannabis cultivation on private lands in and near remote, forested watersheds of northwestern California. This area has supported decades of illegal cultivation and today, includes both legal and illegal cannabis grows in the same watershed.

The State Water Resources Control Board’s Cannabis Cultivation Program reviews observations from the field in a part of the state that has not been historically reported on with a piece titled link opens in new window“Two Years After Legalization: Implementing the Cannabis Cultivation Policy in Southern Coastal California” (PDF). Some of the initial findings indicate that ninety four percent of the 519 enrollees in the Cannabis General Order are discharging their industrial wastewater to publicly owned treatment plants, while the remaining enrollees haul their industrial wastewater to a permitted wastewater treatment facility. Along with this, the unit has also supported state and county enforcement efforts and inspected numerous illegal cultivation sites and observed activities that could be detrimental to water quality and numerous fish and wildlife species.

Researchers from the University of California, Berkeley and CDFW present a piece titled link opens in new window“Coexisting with Cannabis: Wildlife Response to Marijuana Cultivation in the Klamath-Siskiyou Ecoregion" (PDF), which examines local wildlife community dynamics on and nearby active private-land cannabis farms. Using camera data collected between 2018–2019, scientists monitored numerous wildlife species within the Klamath-Siskiyou Ecoregion in southern Oregon. The results suggest that cannabis farms were generally occupied by smaller-bodied wildlife species, and had a higher proportion of domestic dogs, cats and human activity as compared to nearby comparison sites. They conclude that wildlife will likely have species-specific responses to cannabis cultivation and suggest the need for educational resources on wildlife-friendly growing practices.

Learn more about other cannabis research studies in this issue and what scientists are learning, including reviews of the potential impacts of pesticides, artificial light, noise pollution and trash.

For over 100 years, the California Fish and Wildlife scientific journal continues to publish high-quality, peer-reviewed science that contributes to the understanding and conservation of California’s wildlife. We look forward to the contributions of the next installment.

Media Contact:
Janice Mackey, CDFW Communications, (916) 207-7891

Categories: Science Spotlight
  • October 22, 2020

Unarmored threespine stickleback

scientist capturing fish in a drying pool in a steep rocky area - click to enlarge in new window
CDFW staff capture UTS from a drying pool in Fish Creek. Click to enlarge

retrieving fish from a minnow trap in a shallow creek with tall trees - click to enlarge in new window
UTS removed from minnow traps in Fish Creek. Click to enlarge

scientist releasing fish in a creek next to tall weeds - click to enlarge in new window
Jennifer Pareti releases UTS into Soledad Canyon Creek. Click to enlarge

fish being released in a shallow creek - click to enlarge in new window
UTS released in Soledad Canyon Creek. Click to enlarge

Of the many large wildfires that destroyed millions of acres around California during the 2020, one blaze in particular threatened to wipe out years of fishery conservation efforts. The Lake Fire in Los Angeles County burned more 31 thousand acres and it illustrated – for the second time in four years – what lengths dedicated biologists will go to in order to preserve California’s Unarmored Three Spine Stickleback (UTS). The UTS, Gasterosteus aculeatus williamsoni, is a state and federally listed endangered species and a State of California Fully Protected Species.

The story of this rescue actually began in 2016 when a different fire – the Sand Fire – left multiple feet of sediment settling into Soledad Canyon Creek. CDFW fisheries biologists jumped into action to manually rescue about 150 UTS. The biologists transported the fish to a CDFW hatchery, where they remained for about six months while biologists planned the next move back to the wild. Fish Creek, near Castaic Lake, was selected as an appropriate spot for the relocation, and the biologists were right. The transplanted UTS have been breeding and doing well in that body of water for the last several years.

That’s until part two of this story presented itself. When the Lake Fire presented a new possibility of sediment flow into Fish Creek, the biologists again had to take action. This time, about 300 fish were collected and moved again – this time, in a sense, returning back home.

“When the Lake Fire came across, we watched in horror as the whole upper watershed burned,” said CDFW Inland Fisheries Senior Environmental Scientist John O’Brien. “We knew the situation would be dire as soon as we started getting storms this winter. Once we saw the estimations of the sediment that would come down in the system, it was clear we should take some action. We reached out to our federal partners who co-manage the species with us and we all agreed the best thing to do would be to take some of the fish – as many as we could reasonably get in one day – and bring them back to Soledad, where they came from originally. That habitat has recovered quite nicely (since 2016), so the timing was good.”

O’Brien credited the successful effort to CDFW environmental scientists Jennifer Pareti (the project lead), Russell Barabe and Matt Lucero, as well as scientific aides Marissa Groenof, Mike Stephens, Karen Boortz, Austin Sturkie and Thompson Banez.

“We used minnow traps to trap the UTS, and because we’ve had high heat over the past couple of weeks, we used nets to get them out of small, isolated pools that were drying back,” said Pareti. Like her boss, Pareti was instantly worried about the fisheries impacts when the fire began.

“Honestly, you see these fires start and you watch them take off, and we can only sit on the sidelines (while it’s happening),” she said. “Once the fire is under control, we can get in and start doing the next set of work. We have to look at what we can we do to help the resources. How can we help the fish perpetuate through this giant hurdle that’s ahead?”

Even though it was the same species of fish being moved each time into and then out of Soledad Canyon, it wasn’t literally the same fish. “They’re an annual species, which means they only live about a year,” Pareti explained. “Some of them might live into their second year, but the fish we moved are a generation or two removed from the first batch that was moved in 2016.”

Knowing they’ve helped a species that’s struggled to keep itself going brings great satisfaction to O’Brien and his staff.

“Because of the emergency situation of this fire, we weren’t able to do a really robust and thorough count, but we estimate that we took about 70 percent of the fish that were there,” O’Brien said. “They (UTS) are, along with the Southern California steelhead, the most endangered fish we have in Southern California. Those fish species are literally on the edge of being able to continue to exist. Whenever there’s a threat to a UTS population, we take it very seriously,” said O’Brien.

The team plans to continue to monitor the waters for the UTS – not just those at Soledad Canyon Creek, but also Fish Creek, which will recover from the fire damage naturally over time. “Maybe some of those fish (we didn’t capture) will survive,” said Pareti. “Ideally, that stream will provide a long-term opportunity for this species so we can help to expand the population.”

To learn more about UTS, please visit the CDFW website.

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Media Contact:
Tim Daly, CDFW Communications, (916) 201-2958

CDFW photos

Categories: Science Spotlight
  • October 15, 2020

Market Squid Reproducing. Photo credit: Mark Conlin Photography

chart showing monetary value of various commercially fished species, 2015-2019 - click to enlarge in new window
Highest value marine fisheries, 2015-2019 - click to enlarge

fishing fleet ship using a net to catch squid on the ocean - click to enlarge in new window
Squid fishing fleet near Monterey. CDFW photo by Carrie Wilson - click to enlarge

three fishing fleet ships with lights at night on the ocean - click to enlarge in new window
Squid fishing fleet at night. CDFW photo by Carrie Wilson - click to enlarge

Arriving on the heels of the farm to fork movement, the COVID-19 pandemic has disrupted supply chains and altered product demand, which has inspired businesses to restructure and Californians to pay particular attention to where their food comes from. Many understand that almonds, artichokes or lettuce are grown in their own backyard, mostly in the Central or Salinas Valleys. But when residents are asked about wild-caught food sources coming from the ocean, tuna, salmon or perhaps rockfish might immediately come to mind. While those are indeed popular fisheries, the largest of California’s commercial fisheries actually target invertebrates, not fish!

Invertebrates are animals without a backbone, such as the tidepool favorites, sea stars and anemones. But there are many more invertebrates around the world, both swimming and sedentary, that are highly sought after for food – and their popularity is on the rise. California’s largest marine commercial fisheries in terms of volume and value are market squid and Dungeness crab, with well over 100 million pounds landed and more than $30 million in revenue in a typical year for the squid fishery.

Market squid, the invertebrate known to diners as the popular dish calamari, use ocean currents, jet propulsion and prehistoric instincts to travel up and down the continental shelf of California. These slippery siblings of octopuses live very short lives (less than nine months) and produce heaps of eggs, somewhere on the order of 2,000 to 7,000 per female!

When conditions are right, squid show up in droves to reproduce in coastal waters. After reproducing for just a few short days, they die as a natural part of their life cycle. This means the entire population replaces itself in less than a year. These qualities lend to a high volume of squid available for fishermen, cost-effective management and a sustainable fishery. Squid are also used as bait to catch a wide variety of fish species and can be found at many coastal tackle shops or on live bait barges, mostly in Southern California.

If you see very bright lights from groups of boats on the water at night, it is likely the squid fishing fleet in action. Fishermen have used this technique for more than a century because squid are attracted to the lights, which mimic the moonlight. As described in an historic Fish Bulletin from 1965, the market squid fishery began in Monterey around 1863. The early fishing methods involved rowing a skiff with a lit torch at the bow to aggregate the squid. Then, two other skiffs would maneuver a large net around the school.

In today’s fishery, squid are typically caught using a purse seine, a large circular net which is “pursed” at the bottom to contain the school. Once the school of squid is brought closer to the vessel, a long tube is then used to suck the squid out of the net and onto the boat.

Only a limited number of vessels may fish for squid in California, and during the weekends (from Friday afternoon to Sunday afternoon) squid fishing is closed to allow for uninterrupted reproduction. In many fisheries, highly sophisticated mathematical models are used to estimate the available population for an upcoming season and ultimately to decide how many fish can be sustainably caught. Because market squid are short-lived, highly responsive to ever-changing environmental conditions and do not behave like most fish, traditional models are ineffective.

For this reason, the fishery is monitored using the egg escapement method, which is essentially an estimate of how many eggs are released prior to female squid being caught. By comparing the average number of eggs that a female squid will produce to squid samples collected at the docks, biologists can calculate how many eggs were produced each year. This is used to look for trends or major shifts in how the squid fishing fleet is interacting with the stock. Biologists continue to explore ways to pair egg escapement information with population estimates, environmental variables, fishing behavior and economics.

Fishing for market squid is a long-standing tradition in California and normally provides for a large export market. But a number of recent factors, including the COVID-19 pandemic, have inspired stronger local markets for many fisheries, such as squid. This means more restaurants, businesses and consumers are buying directly from the docks, shortening the distribution chain. Boat captains, crew, processors, distributors and diners eagerly await the arrival of squid, especially around spring and summer on the central California coast when fishing is generally the most successful. If history repeats itself, vessels will move to Southern California in the fall and winter, where the Channel Islands tend to be the hot spot for squid fishing. But in response to a changing climate, the range for this species is likely to expand northward, forcing the fishing industry and the biologists studying squid to adapt as well!

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Media Contact:
Kirsten Macintyre, CDFW Communications, (916) 804-1714.

Categories: Science Spotlight