Featured Scientist

A Sierra Nevada red fox dashes into the wilderness after being caught and released as part of an ongoing CDFW study. CDFW image by Corrie McFarland.


Jennifer Carlson on a Roosevelt elk capture in Humboldt County.

Jennifer Carlson is an environmental scientist with the Wildlife Management Program in CDFW’s Northern Region. Based out of Redding, she is one of two unit biologists covering Shasta and Trinity counties. Her biggest current project is working on Sierra Nevada red fox, a state-threatened species, in the Lassen Peak Region, and she is a member of the long-standing Sierra Nevada Red Fox Working Group. In addition, Jennifer has an elk project waiting in the wings and recently conducted the first helicopter survey in her area to attempt to count the different herds in her unit. Her other responsibilities include responding to human-wildlife conflicts and providing expertise and advice to hunters and the public.

Jennifer received her Bachelor of Science degree in Wildlife Management with a minor in Statistics from Humboldt State University in 1999. She also received her Master of Science in Forestry from Cal Poly San Luis Obispo in 2006. She started her career with CDFW in 2005 in the Timber Harvest Review program in the Northern Region. In 2012, she joined the Wildlife Management Program in her current position. When she is not working, she enjoys spending time with her family skiing, camping, hiking, hunting and fishing.

Who or what inspired you to become a scientist?

My family was instrumental in my inspiration to become a wildlife biologist – particularly my dad. He earned his B.S. in Biology and Chemistry and was a self-taught entomologist. He worked for the department in the 1960s as a scientific aid. But at that time it was difficult to get on with the department as a permanent employee, and he never did get hired. Growing up he would take us on nature hikes and quiz us on all the flora and fauna we saw along the way. His own love of the outdoors started with camping and fishing in the central Sierra Nevada with his grandparents (my great-grandparents) when he was a child and it became a family tradition. It became a summer ritual that we carry on today with my own family – a total of four generations!

What is a typical day like for you at work?

As a unit biologist you don’t always know what the day will hold. When one of the aspects of the job is dealing with nuisance wildlife and the public, you could be getting called out to dart a bear that has found its way into town, or a deer that is stuck in a fence. It can include visiting sites to assess property damage caused by a bear, mountain lion, beaver, or bobcat and issuing a depredation permit. In addition to that there are annual wildlife surveys I am responsible for, including deer, band-tailed pigeons, pronghorn antelope, and elk. I also have special projects I work on and am responsible for overseeing, particularly the Sierra Nevada red fox project in the Lassen Peak area. Running a project from start to finish is very time consuming and takes up a lot of my day, especially during the height of the field season. I help out on other projects that my colleagues run, including capturing and collaring deer and elk, fecal DNA projects on deer and elk, and baited camera stations for mid-size carnivores.

What has been the most challenging, and rewarding aspects, of your study of the Sierra Nevada red fox?

We don’t know much about the Sierra Nevada red fox. We think their numbers in the Lassen area may be less than 20 -- we have a minimum population count based on collaring and genetics of 11 individuals currently. Small populations are difficult to study so this one has been a challenge from the start, and it has been compounded by the rugged terrain and conditions that these foxes live in all year-round. With the snowfall we had this past winter, maintaining functional traps has been a challenge, as has keeping our satellite collars working properly. No matter how much we try to alleviate all the obstacles we anticipate, there will always be a level of uncertainty when working on a wild animal in its natural environment that you must accept as a wildlife biologist. But there are great things we have learned from this project that we didn’t know before. For example, we found and documented the first Sierra Nevada red fox den since the early 1900s. We have some amazing video footage of red fox behavior at the den site as well as vocalizations never heard before. We captured, collared and released back into the wild three females and one male red fox. We documented for the first time an inbreeding event where siblings reproduced and had one pup together. We have also learned that these foxes don’t stay at a low elevation throughout the entire winter, as had previously been thought; instead, they will travel back and forth to the higher elevations around Lassen Peak that we thought they only used in the summer.

Tell us about your upcoming elk study.

The goal of the elk study is to estimate abundance, which is difficult with a wide-ranging species that often uses locations that hinder traditional survey methods. To do this, we will capture and collar cow elk in several different herds to learn their movement patterns and apply two different survey techniques to help estimate abundance. The primary technique will be using a helicopter to survey the different herds and count all individuals sighted in each group – both collared and uncollared. Using this data, you can create a “sight ability” model to estimate how elk many you missed and calculate the population size. The other technique would involve extracting DNA from fecal pellets to identify unique individuals and estimate number of individuals in the population. The satellite radio collars will also give us valuable data on habitat use, resource selection, behavior, disease and cause-specific mortality. This will allow the department to develop a long-term elk monitoring program that our recently released Elk Management Plan outlines for the Northern Region. The project will take place primarily in Shasta County (east of Interstate 5) and possibly Trinity County and will hopefully start in the late fall or early winter of this year.

If you had free reign and unlimited funding, what scientific project would you most like to undertake?

It would be hard for me to pick just one project! I would like to help restore a genetically healthy Sierra Nevada red fox population to its historic range. The Sierra Nevada red fox populations that we have left in the state are severely inbred or their genetics have been compromised by other montane (high-elevation) sub-species and/or non-native individuals that have entered the populations. In the last few years we have learned that there are also Sierra Nevada red foxes in the central and southern Cascade mountains of Oregon, although we don’t know the extent or status of that population. I would implement a translocation project that would move individual foxes from their current population into a new one to facilitate “genetic mixing” and increase genetic health. Once we had genetically healthy populations, then I would like to see them reintroduced into areas that they used to occupy, like on and around Mt. Shasta.

I also would like to undertake a massive elk project that was scientifically sound and robust, with an army of people working on it in the Northern Region. With those resources, we should be able to come up with an accurate population size for elk in our region relatively quickly.

What is the best thing about being an environmental scientist?

One of the best things about my job is that I get to be in the outdoors and explore places I never would have been to otherwise. To be able to study one of the rarest mammals in California, the Sierra Nevada red fox, and provide new information on the life history of this elusive canid has been one of the highlights of my career. Flying in a helicopter counting big game species is something I always dreamed about when I was in college and now I am doing it. Some days I have said to myself, I can’t believe I am getting paid to hike on this trail or fly in a helicopter today!

CDFW Photos. Top Photo: Jennifer Carlson cradles a Sierra Nevada red fox that was captured and collared in the Lassen National Forest. CDFW image by Pat Sater.

Don Baldwin surveys rainbow trout at the headwaters of a small coastal stream in San Luis Obispo County. These wild trout serve as a seed population for coastal steelhead as some of their progeny may migrate out to the ocean.


Don conducts a snorkel survey on San Luis Obispo Creek.


Before he began monitoring steelhead in San Luis Obispo County, Don worked as a steelhead biologist in the Central Valley.


Don takes a summer hike to the summit of Mount Lassen to ski off the top.


A passionate backcountry skier, Don tours the Sierra through Yosemite National Park.

Don successfully completed CDFW’s Heritage Trout Challenge by catching six different native California trout in their historic range.

Don Baldwin is an environmental scientist with CDFWs Central Region based in San Luis Obispo. A 12-year CDFW employee, Don oversees the California Coastal Monitoring Program in the area and is tasked with surveying and assessing South Central California Coast steelhead, a threatened species listed under the federal Endangered Species Act. Steelhead are the anadromous population of rainbow trout that spend time in both the ocean and freshwater.

Born and raised in Sacramento, Don developed a love of trout and steelhead while growing up fishing the American River and small trout streams in the Sierra. His passion for steelhead in particular has influenced his education and career choices ever since. He holds a wildlife management degree from Humboldt State University – a school he chose in no small part due to its proximity to so many great north coast steelhead rivers.

When you think about some of the hallowed steelhead regions and waters of California, San Luis Obispo is not exactly top of the list. Can you explain the work you are doing there?

We are trying to get a grasp of what the wild steelhead population is in San Luis Obispo County. Since 2017, I have been implementing the California Coastal Monitoring Program there, which is part of our statewide responsibilities to monitor and recover these listed coastal salmon and steelhead populations under state and federal endangered species laws.
There are a lot of small, coastal streams in the county – approximately 25 plus their tributaries – and a lot of those are spring-fed with good, cold water with lots of wild rainbow trout in them. But not much research has been done so nobody really knows the population status of steelhead in the county.
Right now, I am looking for adult steelhead in the two priority coastal streams there – San Luis Obispo Creek and Santa Rosa Creek, the latter of which is in Cambria. We do that two ways: surveying for redds (fish nests) and using DIDSON sonar cameras to count the adults migrating upstream to spawn. We then build a mathematical relationship to estimate the number of adult steelhead for each redd we see. I am still in the preliminary stages of this monitoring program and have a way to go until we finalize our entire sample frame.

Are you finding many fish?

We did some redd surveys last year and we did find some redds, but never saw any adults while conducting spawner surveys. We’re still processing all the DIDSON data and have seen a few adult steelhead. I’m extremely optimistic we will see more. The last few years have been tough on steelhead in central and Southern California because of the drought, but they are a very resilient species. They have gone through this before. They’ve been around for thousands of years. They may have experienced droughts that have lasted 10, 20 years, but they keep coming back. So it’s exciting to be part of this project and monitoring these fish, yet it is challenging because they are so elusive and difficult to monitor. Hopefully, with these good rain events we are having this year, producing good flows, we will start seeing more fish.
What’s really special about this species is that there is this residence component of rainbow trout up in the headwaters of these streams that serves as a sort of seed bank for the anadromous component. They’ll just hang out and keep reproducing over the years and once the time is right, some of the juveniles may go out to the ocean.

Steelhead fishing opened on many coastal streams in December and January. Where would you direct steelhead anglers in San Luis Obispo County?

Go to the Eel River (in Humboldt County) (laughs). The streams in San Luis Obispo County are very small, some only a couple of miles long. Those that are open to fishing are open only in very small stretches on select days. You really need to read and understand the local fishing regulations. Many streams run through private property with no public access. There are just not a whole lot of fishing opportunities nor are there many fish.
To really immerse yourself in steelhead fishing and culture, go to the Eel River or Smith River (Del Norte County) and hire a guide with a drift boat. That’s how you have a chance to hook into a large chrome bright steelhead.

Can you explain the fascination with steelhead to somebody who’s never fished for them?

As a rainbow trout that goes to the ocean, they just get so much bigger, more powerful and strong. They are very elusive. You rarely see them. They return to freshwater, spawn, and then they are gone. Fishing for steelhead is like chasing ghosts, you always want to see what’s around the next corner.
They’re an absolutely beautiful fish. They fight hard and they’re exciting to catch. The appeal is the chase. When I first started steelhead fishing, I would go out for days and months and never catch anything. But I kept going back. I always heard it takes 300 hours of fishing before you start hooking them. And that’s pretty much it.

Anything surprising ever show up in these streams you are monitoring?

In San Luis Obispo County, we only have one species of salmonid: steelhead. We don’t have Chinook or coho salmon down there. The cool thing is that we have Pacific lamprey. Recently, that’s been the southernmost extent of their range. However, for about 10 years, we didn’t see any lamprey in San Luis Obispo Creek. They were nonexistent.
Down by the estuary there’s a saltwater intrusion weir with a fish ladder that wasn’t functioning well. A couple of years ago a “lamp ramp” was installed on the weir – which is a lamprey passage ramp made from a piece of curved sheet metal. Lamprey can’t scale a 90-degree angle as they use their mouths to suction-cup their way upstream over wetted obstacles. Ever since the lamp ramp was installed, we’re seeing adult lamprey, lamprey redds and a lot offspring once again in San Luis Obispo Creek.

Are lamprey a type of eel?

No. They look like an eel but don’t have paired fins or jaws like an eel. They are a completely different species. We don’t have freshwater eels on the West Coast. They have those on the East Coast. Adult lamprey have a round, sucker-like mouth and are parasitic when in the marine environment. They attach and feed on marine fish, including salmon and steelhead in the ocean.
Lamprey are a remarkably interesting species. They are an anadromous species like steelhead and salmon. They come into freshwater and hunker down in the gravel for a year without feeding. They absorb all their nutrients into developing their gonads and then come out a year later, dig a redd, spawn and die. They produce thousands of young that will live in the gravel for up to six, seven years. And they’re filter feeders, so they are aerating the stream bed and cleaning the water. Once they get to the size of about a pencil, they will migrate out to the ocean, grow up, and return one to three years later to spawn.

If you had free reign and unlimited funding, what scientific project would you most like to do?

I would be doing exactly what I’m doing right now and just really build a huge monitoring program. It really takes an army to do it well. You really must have multiple crews to go out and collect field data. You need a crew processing sonar data. You need a lot of equipment and sampling gear, especially when we start monitoring juvenile steelhead in the future. It takes a lot of people, equipment and money. Right now, it’s just me and a couple Watershed Stewards Program (WSP) members a day or two a week trying to do everything. So I would love to have free reign and staff and money to really monitor steelhead throughout San Luis Obispo County so we could really understand and tell their story and put this program on the map.

Tell us something about yourself many people would be surprised to learn.

I’m a ski bum. My true passion is backcountry skiing in the high Sierra and southern Cascade mountains. I started skiing when I was 5 and spent a lot of time in the mountains growing up. I don’t ski as much as I’d like to these days, but I still get out there a few times a year.

CDFW Photos. Top Photo: An avid fly fisherman, Don shows off a coastal cutthroat trout he caught in northern California before releasing it.

Fishing for night smelt from the beach in Pacifica.


Fishing for night smelt from the beach in Pacifica.


Ken Oda holds a soupfin shark caught while capturing California halibut for a hooking mortality study.


Ken Oda piloting the research vessel Triakis on San Francisco Bay while doing Pacific herring surveys.  

Ken Oda is an environmental scientist with CDFW’s Marine Region and a member of the Northern and Central California Finfish Research and Management Project. Based out of the Monterey office, Ken is also the lead person for sandy beach surfperch research and management.

Where did you grow up?

I was born and raised in Monterey. My great-grandfather operated a sardine cannery on Cannery Row, and my grandfather ran a wholesale fish business on Wharf 1 in Monterey, specializing in local abalone.

What led you to a career in marine biology?

It’s genetics. My mom’s family was in the commercial fishing industry. My dad was an avid fisherman and diver. I became fishing-obsessed at a young age and wanted to learn everything I could find about fish. Given my strong interest in fish and all things fishing, my parents “suggested” that I choose a career path consistent with my fish fascination.

After searching for colleges offering fisheries degrees, I decided that Humboldt State University could offer me the best education. I graduated from Humboldt State with a Bachelor of Science degree in fisheries, with a mariculture emphasis.

In 1982, my mom went to the annual open house at the CDFW’s Granite Canyon Mariculture Laboratory in Big Sur. She had a conversation with the director, Earl Ebert, who invited me to do my senior thesis at the lab as a volunteer student intern. My job entailed taking care of juvenile Red Abalone. Later, my first paying position was as a scientific aid sampling sport and commercial rockfish landings from Monterey to Santa Cruz. I worked as a fisheries technician on groundfish for the Pacific States Marine Fisheries Commission. By 1988, I began my first permanent position as an entry level marine biologist. Later I promoted to marine biologist conducting population assessments on San Francisco Bay herring. In 2005, I transferred back to Monterey, which eventually landed me on my current project.

What inspires you?

The learning opportunities. I remember reading vintage issues of CDFW journals and informational publications, e.g., ocean fishing maps and fish identification books, and thought that I’d want to do that kind of work someday. I had the privilege to meet and work with ichthyologists Dan Miller, Dan Gotshall and Bob Lea, who authored the publications that I had read.

I’m also inspired by the fact that I’m working on surfperch fisheries that my family have been active participants in since the 1910s.

What is a typical day like for you at work?

The best thing about my job is having daily opportunities to learn something new while in the field, interacting with others or through data analysis.

I’m doing more writing than fieldwork these days, but on those days when I can get out of the office, I head to a local beach to collect surfperch. To do so, I gather up my fly and/or conventional rods and reels, a tackle bag/soft cooler, electronic thermometer, and a smart phone for taking photos and storing data in the field. If successful, I’ll bring the fish back to the lab and collect life history information from them: lengths, weights, sex, maturity, and ear bones (otoliths) used for age determination and input the data into a spreadsheet.

When I’m not in the field, I check and respond to emails and phone calls, and search for publications to support the reports that I’m writing.

What interesting projects are you working on currently?

Writing “Enhanced Status Reports” (ESRs) as part of the implementation of the 2018 Marine Life Management Act Master Plan for Fisheries. The ESRs describe the individual species or species groups, habitat, research and management, and the state-managed fisheries that they support.

What accomplishment are you most proud of?

I was the project lead person that coordinated the purchasing process for building a custom research boat for the Pacific Herring Project. This was the first for the Marine Region in many years. The process from the funding proposal to delivery of the boat took about three years. It took a team of CDFW staff, consultations with commercial fishermen, boat builders and naval architects and engineers to pull it together and deliver a boat that is still in service after 20 years.

Over the course of your career, was there a discovery or an incident that surprised you?

During the 1997 El Niño storms when levees in the Delta broke and caused widespread flooding, it was not unusual to see random items drifting around in San Francisco Bay while doing surveys — a travel trailer, dead cattle, snakes, a refrigerator.

What are the best – and most challenging – things about being a fish and wildlife scientist?

I appreciate feeling “dialed in” with the fish species through field work and seeing fish in the flesh. Fish and fishermen are more than numbers in a table or points in a graph and observations sometimes can’t be captured on paper or camera.

The most challenging aspect is presenting information that you know won’t be popular to a group of people and trying to remember that you’ve done your best despite their reactions.

If you had free reign and unlimited funding, what scientific project would you most like to do?

A statewide quantitative survey of surf species using fishing rod castable armored cameras and a fleet of four-wheeled ATVs.

Away from work, where are we likely to find you?

Fishing somewhere — on a tropical flat, a coastal river for steelhead, or the Delta for striped bass. I’m happy fishing anywhere for just about anything.

Tell us something about yourself that many people would be surprised to learn.

I played competitive volleyball, which resulted in two surgeries and broken fingers.

Do you have any advice for people considering careers in science or natural resources?

Realize that it’s a very competitive field these days for jobs, prepare accordingly, take opportunities to meet those working in the field that have taken similar career paths and volunteer to determine if a job/career is what you really want. Keep an open mind — we never know it all.

CDFW Photos courtesy of Ken Oda. Top Photo: Ken Oda at work collecting surfperch in his Sandy Beach Surfperch Research and Management project.