Recent accomplishments of CDFW's scientific community
The California Department of Fish and Wildlife (CDFW) has completed its annual waterfowl breeding population survey.
Mallards, gadwall and cinnamon teal comprised 54 percent of the ducks observed, down 30 percent from last year. The number of mallards decreased from 263,774 to 198,392 (a decrease of 25 percent) and total ducks decreased from 417,791 to 396,529 (a decrease of five percent).
The most notable decrease occurred in the Sacramento Valley area, where mallards were estimated at a record low of 31,000 (73 percent below the long-term average).
Given the abundant precipitation, one might expect the numbers to be higher. In some parts of the state, it did indeed increase available habitat (uplands and ponds). But in many areas, last winter’s heavy rains largely resulted in deep, fast-flowing water, which is not ideal for dabbling ducks. Other reasons for low duck observations could include winter flooding of nesting habitat that normally remains dry, the late-season flooding of the rice fields in the Sacramento Valley and the conversion of rice fields and pastures to tree crops.
CDFW biologists and warden pilots have conducted this annual survey using fixed-wing aircraft since 1948. This year’s survey was conducted from April 3 through May 4 in the Central Valley, and May 9-10 in northeastern California. The population estimates are for the surveyed areas only, which include the majority of the suitable duck nesting habitat in the state. Surveyed areas include wetland and agricultural areas in northeastern California, throughout the Central Valley, the Suisun Marsh and some coastal valleys.
The full Breeding Population Survey Report can be found at www.wildlife.ca.gov/conservation/birds/waterfowl.
The majority of California’s wintering duck population originates from breeding areas surveyed by the U.S. Fish and Wildlife Service (USFWS) in Alaska and Canada. Those survey results should be available in early August. CDFW survey information, along with similar data from other Pacific Flyway states, is used by the USFWS and the Pacific Flyway Council when setting hunting regulations for the Pacific Flyway states, including California.
Scientists with the California Department of Fish and Wildlife (CDFW) and Oregon State University recently published the results of a population study on fishers (Pekania pennanti) in northern California and southern Oregon. Led by CDFW Wildlife Statistician Dr. Brett Furnas and three coauthors, CDFW Senior Environmental Scientist Richard Callas, CDFW Research Analyst Russ Landers and Dr. Sean Matthews of Oregon State University, the study produced the first-ever robust estimates of density and size of the fisher population in northern California.
“This is the first time we’ve come up with a solid number of fishers, which is a starting point for tracking and monitoring populations,” Furnas said. “One of the most important tools we have used so far to help this species is reintroductions, so now -- with a baseline established and ongoing surveys planned -- we’ll be able to see if the population is really rebounding over time.”
Fishers in northern California and southern Oregon represent the largest remaining population in the Pacific states. The species once ranged from the state of Washington southward through Oregon and California. Currently, fishers occupy only a small portion of their historical range in that region. In California, fishers are found in the northern areas of the state and a small, isolated population occurs in the southern Sierra Nevada Mountains.
CDFW and the U.S. Fish and Wildlife Service have been petitioned on several occasions to list fishers as threatened or endangered under their respective Endangered Species Acts.
In 2016, while considering fishers in the southern Sierra Nevada Mountains of California, the California Fish and Game Commission voted that the petitioned action was warranted in part, choosing to accept the petition in the context of the Southern Sierra Nevada Evolutionarily Significant Unit, and adopted findings to that effect, which were published on May 6, 2016. Although fishers are relatively well-distributed in northern California and in portions of southern Oregon, data from existing surveys and prior studies was used to estimate abundance. This information is critically important to assess the status of fishers and serve as a baseline for conservation efforts.
Furnas and his coauthors used data from camera traps, hierarchical modeling of detections and non-detections of fishers from the cameras, and information about fisher home range size to develop their estimate of population size. They estimated that approximately 3,200 fishers occur within the northern California and southern Oregon study area, with an average density of 5.1 to 8.6 fishers per 100 square kilometers.
Estimating the sizes of wildlife populations is challenging, particularly for species such as the fisher that are difficult to observe and occur over large areas. A final population estimate for the fisher would not have been possible without the cooperation of a variety of federal and tribal agencies, universities and private landowners who shared datasets that were combined to complete the modeling. With these data, Furnas and his coauthors demonstrated that estimating the population size of the fisher at large geographic scales is feasible. They also suggested that the methods used in their research could be used to estimate the abundance of other carnivores, including black bear, gray fox and coyote.
The study was published in the journal Ecosphere. More information / view publication
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:
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.
It does not take a leap of faith to believe that CDFW scientists have gained the upper hand in bolstering the population of yellow-legged frogs in the High Sierra.
Over the past three decades, Sierra Nevada yellow-legged frogs have become imperiled in California due to the two-pronged impact of introduced (non-native) trout and chytridiomycosis, a disease that is affecting amphibians worldwide.
Past introduction of non-native fish, including rainbow trout and golden trout, to benefit sport fishing in the High Sierra took a heavy toll on the species. High-elevation lakes where these frogs once flourished were largely fishless until fish stocking came into vogue. As the years passed, scientists determined that these introduced fish were depopulating the frogs by competing for food sources (primarily insects) and by predation (trout ate both adult frogs and their tadpoles). Chytridiomycosis, which affects many frog species, also impaired the ability of the Sierra Nevada yellow-legged frog’s skin to exchange vital nutrients, which often leads to death.
As a result, Sierra Nevada yellow-legged frogs are believed to have vanished from approximately 92 percent of their historical habitat, and halting and reversing that decline has become an important goal of CDFW, as well as other state and federal entities.
“This is an animal that only lives in the Sierra Nevada,” said Sarah Mussulman, a CDFW senior environmental scientist. “It is one of our unique California species that lives in high-elevation areas, and as an amphibian it serves as an important link between the terrestrial and aquatic ecosystems. This link is especially critical in the low nutrient, granitic basins of the High Sierra, where frogs and tadpoles consume insects and algae and are themselves consumed by a variety of snakes, birds and mammals.”
CDFW recently completed two projects as part of its ongoing efforts to reverse the population decline of Sierra Nevada yellow-legged frogs.
The efforts took place at two sites: Highland Lake and Clyde Lake, located approximately seven miles apart on the Rubicon River in the Desolation Wilderness area of El Dorado County. The projects were completed with federal grant funds earmarked for the recovery of endangered and threatened species (the species is listed as threatened by the State of California and as endangered by the U.S. Fish and Wildlife Service).
Highland Lake, along with its outlet, an unnamed stream, and two small adjacent ponds, supported a small population of rainbow trout when the project began in 2012. Trout abundance had declined in the absence of stocking in recent years but sufficient natural reproduction occurred in the inlet to Highland Lake to sustain the population. CDFW began using gill nets to remove rainbow trout -- the descendants of fish planted in the lake by CDFW from 1935 to 2000 -- in 2012, in partnership with Eldorado National Forest personnel.
During a frog-monitoring survey at Highland Lake in 2016, approximately 800 adult frogs were observed, as compared to a 2003 survey in which only a few tadpoles were observed. Because the frogs have consistently survived in this area despite the presence of chytridiomycosis, scientists believe they have a good chance at persisting in the area for a long time.
“Highland really had a population explosion over the past five years and can be counted as one of the most successful projects of this type ever undertaken,” Mussulman said.
The project at Clyde Lake was smaller and had somewhat different factors.
Golden trout, which frequently have the same negative impacts on Sierra Nevada yellow-legged frogs as rainbow trout, including predation and competition for food sources, were planted by CDFW at Clyde Lake from 1932 through 2000.
Once stocking was halted, the golden trout proved less resilient then the rainbow trout at Highland Lake, due to habitat factors.
“Clyde Lake sits in a north-facing granite bowl bordered by 1,000-foot cliffs, and no flowing streams enter the lake,” explained Mussulman. “There was no spawning habitat, which is likely why golden trout did not persist there after stocking was halted.”
The stream flowing out of Clyde Lake and four nearby ponds did support a small population of golden trout after plants were halted. The fish in the stream and ponds, which are self-sustaining populations, are precluded from moving from the stream into Clyde Lake by a fabricated dam. In 2013, frogs and a few tadpoles were observed in the stream alongside fish, and CDFW began removing the fish from the stream with gill nets to provide additional habitat for the frogs.
Nine years of monitoring data collected by CDFW scientists indicate that the area’s Sierra Nevada yellow-legged frog population, while small, is slowly increasing. Surveyors observed more than 120 frogs in 2016, compared to a low of six observed in 2005. Moreover, in 2016, for the first time, dozens of tadpoles were observed in the newly fish-free lower reaches of the stream.
“It is great to see these populations recovering,” Mussulman said. “It is a great privilege doing this work that helps keep these frogs on the landscape.”
CDFW photos: Highland Lake in the Desolation Wilderness, and a Sierra Nevada yellow-legged frog
If you’re an avid marine sport angler, you have most likely seen the smiling faces and brown polo shirts of California Recreational Fisheries Survey (CRFS) samplers. Since its inception in 2004, CRFS has grown into one of the state’s largest and most important survey efforts. Survey samplers are tasked with collecting data about both recreational fishing catch and effort.
Annually, CRFS samplers make direct contact with 68,000 fishing parties at over 400 sampling sites between the California-Oregon state line to the California-Mexico border. A separate but related telephone survey effort contacts an additional 26,000 anglers. A program of this large scale is necessary because recreational fishing effort and success rates are highly dynamic – a large sample size is needed to adequately estimate catch and effort. Recreational fishing effort is also very challenging to predict, as it can be affected by many factors (weather, gas prices, time of year, fishing seasons, etc.). But the recreational sector accounts for a significant portion of overall marine harvest, so it’s essential to collect that data to produce reliable estimates of harvest.
CRFS is part of a larger effort to estimate recreational catch and effort on the west coast and is integral to the national effort conducted by the National Marine Fisheries Service’s Marine Recreational Information Program. This partnership allows CRFS methods to be periodically peer reviewed by expert consultants throughout the country. This review provides certification that the methods meet or exceed national standards and fisheries management needs, and can recommend the use of new methods to address changing needs or to capture emerging fisheries.
There are three parts to the survey. The first is the field sampling component. This consists of in-person interviews conducted for four different fishing modes – beaches and banks, man-made structures, private/rental boats, and commercial passenger fishing vessels. Field survey questions are specific to catch and effort data during daylight hours at publicly accessible sites. The second part of the survey is the telephone survey. Anglers are randomly selected monthly through the state’s online Automated License Data System (ALDS) and asked about effort data (the number of fishing trips taken) at beach and bank sites. The telephone survey also collects data from private boats returning to sites not sampled during the field survey, and private boats returning at night. The third part of the survey is collection of data from commercial passenger fishing vessel logs. Captains submit this information for every trip, and the data is used together with field sampling data to estimate overall fishing effort.
All of this information is used in many ways. In addition to CDFW, the Fish and Game Commission and the Pacific Fishery Management Council use the data to:
How can you help? There are two ways! If you encounter a CRFS sampler in the field, please cooperate and answer the interview questions truthfully. Take the time to allow the sampler to examine and measure any catch. Recreational anglers, particularly those who fish frequently, are more likely to encounter CRFS samplers. Every fishing trip is unique — different target species, success rates, different locations, different gear, etc. — so we ask anglers, “Even if you have completed this survey before, please cooperate each time you are asked!”
Secondly, if you receive a phone call, please say “yes” to the CRFS telephone surveyor. Data collected through this telephone survey is used to estimate fishing effort that cannot be estimated any other way.
Personal contact information is always kept confidential, and the information that is collected becomes part of a public database. To learn more about the CRFS, access the database or download related flyers and brochures, please visit www.wildlife.ca.gov/Conservation/Marine/CRFS.
Fate has not been kind to the San Joaquin kit fox (Vulpes macrotis mutica).
Shrinking habitat caused by urbanization and agricultural expansion landed this Central Valley native on the federal Endangered Species List decades ago. California’s total population of San Joaquin kit foxes may now be down to a few thousand animals. To make matters worse, its favorite food, the kangaroo rat, is likewise endangered as the desert habitat it prefers continues to disappear.
Wildlife biologists took heart, however, in a population that seemed to be thriving within the city limits of Bakersfield. Unlike San Joaquin kit fox populations in other parts of the Central Valley range, the Bakersfield foxes adapted quite nicely to urban life. Their number – estimated between 200 and 400 animals – has evidently seemed to be holding steady and possibly increasing.
Their cute and cuddly appearance make them popular with city residents. Earlier research showed the population was healthy and genetically robust. Wildlife biologists were counting on those urban foxes to ensure the species’ survival should kit fox populations completely collapse elsewhere.
Today, those Bakersfield kit foxes are under siege, suffering from an outbreak of highly infectious sarcoptic mange. Mange – a skin condition caused by parasitic mites -- leads to hair loss, open wounds from scratching and, ultimately, death. The first case was detected among the kit fox population in March 2013, and since then, more than 200 cases have been documented. The epidemic has grown worse every year.
Given the importance of the Bakersfield population, CDFW, the U.S. Fish and Wildlife Service, the California State University, Stanislaus, the University of California, Davis (UCD), and various nonprofit wildlife groups have all joined forces to combat the mange.
Jaime Rudd, an environmental scientist in CDFW’s Wildlife Investigations Lab in Sacramento, is leading CDFW’s efforts while simultaneously writing her UCD Ph.D. dissertation on the outbreak. Rudd is researching ways to prevent mange from spreading to healthy animals, and assisting Stanislaus State’s Endangered Species Recovery Program with trapping and treating diseased foxes.
Severely diseased kit foxes are trapped and transported to the California Living Museum, a Bakersfield wildlife rehabilitation facility and zoo. There, the kit foxes are hospitalized, given life-saving antibiotics and fluids and treated with a topical pet product that kills the mites. The foxes often need months of treatment before they are healthy enough to release. And although the intervention saves individual lives, the process is costly and time-consuming – and doesn’t prevent the treated fox from getting mange a second or third time.
Rudd is making good use of her undergraduate degree in molecular biology, analyzing the DNA of the mites to see if they might be related to those in dogs and coyotes, which could be spreading the mange to the foxes.
“Essentially, we want to look at their molecular signature to see if these mites are related,” Rudd said.
Rudd is studying a group of wild kit foxes living on the CSU Bakersfield campus, which no doubt are supplementing their diet with burger bits and pizza crusts discarded by college students. Rudd is monitoring the group with trail cameras, outfitting some foxes with radio tracking collars and others with the type of preventative flea and tick collar you might use on a pet dog or cat.
“We want to evaluate the efficacy of these collars,” she said. “If they’re only going to work for two months, the collars won’t help us slow down the spread of mange, so is it really worth the effort of putting them on? But if they’re going to work for five months or more, then it might be worth the effort.”
If there is any hope sustaining Rudd and her colleagues in this important, though often disheartening, work, it’s this: “The fact we are not seeing mange in the outlying populations is cause for optimism,” she said. “If nothing else, we can at least try to keep it from leaving the city.”
Restoration project area. CDFW photo by Andrew Hughan.
Yellow and orange indicate restoration areas at the Ocean Ranch Unit of CDFW's Eel River Wildlife Area.
How does one best go about making an already bountiful and bucolic part of the Golden State even better? Sometimes, perhaps paradoxically, it pays to look to the past in order to be forward thinking in the present.
CDFW, Ducks Unlimited, and many partners have undertaken the Ocean Ranch Unit of the Eel River Wildlife Area Integrative Ecosystem Restoration Project Planning Process to enhance the estuarine and coastal dune ecosystem of the Ocean Ranch Unit in Humboldt County
The approximately 2,600-acre Eel River Wildlife Area was acquired to protect and enhance coastal wetland habitat, and was designated as a wildlife area by the California Fish and Game Commission in 1968. The initial decision to undertake an estuary restoration-planning project began more than a decade ago. After several years of monitoring to gather necessary data, Ducks Unlimited completed a feasibility study, funded by CDFW’s Fisheries Restoration Grant Program and the California State Coastal Conservancy, in December 2015.
The primary goal is to restore and expand natural estuarine and dune ecosystem functions, including the recovery and enhancement of native species (including fish, invertebrates, wildlife and plants) and their habitats. These changes should also help mitigate current and future impacts of climate change. Sea level rise will likely result in saltwater inundation further upstream, which is expected to modify habitats (for example, the loss of tidal marsh migration inland) and the size and shape of the estuary.
The project has been a revelation for Michelle Gilroy, a CDFW district fisheries biologist who works primarily in Humboldt and Del Norte counties.
“For the first time in my 30-year fisheries career, which began in the Eel River watershed, I am achieving a long-time goal of mine: To envision, develop and work through to completion, or near completion, a large restoration project,” said Gilroy. “This exciting project and the extraordinary team I am so very fortunate to work with is making that dream a reality – and in the Eel River estuary, one of California’s largest estuaries. It is definitely one of the highlights of my career.”
Improving the connectivity of tidal and freshwater habitats, and controlling or eradicating invasive plants, are key goals of the restoration project.
A feasibility study guiding the project analyzed the potential for expanding tidal functions within 475 of the 933 acres of the unit to aide in the recovery and enhancement of estuarine habitat and native species. Restoration of these essential habitats is vital to the recovery of anadromous salmonid populations in the Eel River, as estuaries provide critical nursery and rearing conditions for juveniles prior to ocean entry.
The unit is located within the Eel River estuary, a mile and a half north of the mouth of the Eel River and approximately four miles northwest of Loleta. The unit is comprised of a diverse set of habitats, including coastal dunes, riparian woodlands, tidal mudflats, tidal slough channels, salt marshes and managed freshwater marshes.
Prior to second-wave human settlements, this portion of the estuary, then inhabited by Native Americans, consisted primarily of salt-marsh habitat dotted with areas of spruce and hardwood forest, and native grasslands. An abundant fishery, which included the prized salmon, along with native plants, provided sustenance for the Wiyot people who lived around Humboldt Bay and the estuary. As Euro-Americans settled this region, however, they largely drove the Wiyot people off their traditional lands and began to repurpose portions of the environment.
By the end of the 1800s, most of the salt marsh and forestlands were drained and converted to farm and grazing land. This conversion of tidal marshes to pastures was done with purpose – but such perceived progress carried an ecological cost.
The construction of levees and tide gates to drain salt marsh increased sedimentation, flooding, and the amount and diversity of habitat and food supply for fish and wildlife declined throughout the estuary. This degraded the prior functioning, highly productive estuary ecosystem. In addition, invasive species now threaten the diversity or abundance of native species through competition for resources, predation, parasitism, interbreeding with native populations, transmitting diseases, or causing physical or chemical changes to the invaded habitat.
Despite these declines, the Eel River delta, which includes the Eel River Wildlife Area, today continues to provide vital habitat for many aquatic and terrestrial organisms, including state and federally threatened and endangered fish, wildlife and plant species, and many state species of special concern. More than 40 species of mammals and 200 species of birds use the delta area and researchers have documented at least 45 fish species in the Eel River estuary alone.
The area provides essential spawning, nursery and feeding grounds to several commercially and recreationally important species, including Dungeness crab. Estuaries are among the most productive and diverse ecosystems in the world and are one of the preferred habitats for young Dungeness crabs.
Dungeness crabs use estuaries as critical nursery habitat in their juvenile stages, as not only a refuge from predation – particularly in estuaries with structural habitat such as eelgrass – but also because of the abundance and diversity of prey provided by estuaries. Dungeness crabs are opportunistic feeders – clams, fish, isopods and amphipods are their preferred food sources, as well as other Dungeness crabs. Their predators include those larger crabs, octopuses, and fish, including salmon, lingcod and various rockfishes.
Wildlife, of course, is not the only form of life to reap the benefits of this region, as humans enjoy a range of outdoor activities, including fishing, bird-watching, boating, hiking and hunting.
The project is expected to begin in the summer of 2019.
CDFW photos and map
Top photo: CDFW Senior Environmental Scientist Kirsten Ramey and Eric Ojerholm of the Pacific States Marine Fisheries Commission.
Partners, Funding and Staff
Ducks Unlimited, in partnership with CDFW staff, has recently secured project planning funds from the California Wildlife Conservation Board, and initial project implementation funds from the NOAA Restoration Center. To complete the restoration design and environmental compliance process, this second phase of restoration planning will consist of a continued CDFW and Ducks Unlimited partnership, with additional assistance from several local consultants and a Technical Advisory Committee (TAC). The TAC includes representatives from the U.S. Army Corps of Engineers, the Bureau of Land Management, U.S. Fish and Wildlife Service, National Marine Fisheries Service, California Coastal Commission, California State Coastal Conservancy, North Coast Regional Water Quality Control Board, California Sea Grant, California Trout, Humboldt County Resource Conservation District, Humboldt State University, Redwood Region Audubon Society, private landowners, and the Wiyot Tribe. Additional project partners include AmeriCorps, Tom Origer and Associates, Pacific Coast Fish, Wildlife and Wetlands Restoration Association, GHD Inc., H.T. Harvey and Associates, Moffatt and Nichol, Northern Hydrology Engineering, Pacific Coast Joint Venture, and the Pacific States Marine Fisheries Commission.
CDFW staff who have served on the project management team include Michelle Gilroy, Allan Renger, Scott Monday, Kirsten Ramey, James Ray, Mark Smelser, Gordon Leppig, Michael van Hattem, Jennifer Olson, Linda Miller, Clare Golec, Charles Bartolotta, Robert Sullivan, Tony LaBanca, Mark Wheetley, Scott Downie, Adam Frimodig, Jeff Dayton, Mike Wallace, Vicki Frey, John Mello, and Karen Kovacs.
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