Introducing the Behind the Fish Series, where we go one-on-one with various different fishery scientists across the world to better understand a specific species of fish or fishery. From the genetic make-up, feeding habits, fishing techniques, native range, to conservation we dive straight in to learn about the facts that matter and what makes these fish so special.

In this feature, we were lucky enough to catch up with Matt Sloat, a fish ecologist who has dedicated his career to studying salmonids across the west. Matt has spent the past decade studying taimen the largest member of the salmonid family. Check out the interview below as we learn more about taimen and the work that Matt and the Wild Salmon Center are doing to better understand this species.

Flylords: Who is Matt Sloat? 

Matt: I am the Science Director at the Wild Salmon Center, an international conservation organization focused on protecting the healthiest salmon watersheds around the North Pacific Rim. I’m based in Corvallis, Oregon where I’m also a researcher at Oregon State University (OSU) in the Department of Forest Ecosystems and Society.

My work takes me to salmon watersheds in the Russian Far East, Kamchatka, and in North America from Alaska south to the coastal watersheds of Northern California. I also work on Siberian taimen conservation biology in Mongolia. What I do in those places can vary from understanding salmon responses to glacier retreat to quantifying the prey base needed to support giant Siberian taimen. But in general, my research is about understanding “salmon systems”, meaning the physical and biological workings of salmon watersheds and also the systems of management, policy, and governance that shape interactions between salmon and people. At Wild Salmon Center, we use that knowledge to protect and restore habitat, improve salmon management, and support sustainable salmon fisheries. For someone with a lifelong passion for salmon, trout, and rivers, I have a dream job.

Prime Siberian taimen habitat, Tugur River, Russia.

Flylords: How long have you been studying fish and where did the passion come from?

Matt: I started studying fish about 25 years ago, not long after I got deep into fly fishing. My real introduction to river food webs came through learning the life cycles and seasonal progression of mayfly, caddisfly, and stonefly hatches so I could catch more fish. I got my undergraduate degrees in English and Biology at the University of Montana in Missoula, which is a really good school, and was also a great place to be a fly fishing bum at the time. I lived a couple of blocks from a good trout river and I’m sure I spent somewhere around 200 days a year on the water.

I’ve always been passionate about salmon and rivers, though. Until I was eight, my family lived on the Kuskokwim River, a big salmon river in western Alaska. I was raised, more or less, on Kuskokwim kings and moose meat. My dad started taking me sport fishing and subsistence fishing when I was three. Salmon were and always have been an essential part of life.

Waiting for better flying weather in Russia.

Flylords:  Can you tell us a little bit about the work you have been doing with taimen in Russia and Mongolia?

Matt: In Russia and Mongolia, we have been working with local partners to try and safeguard some of the world’s last best taimen watersheds. Taimen are the world’s largest trout. We’re talking freshwater fish that can live well past 20 years and that grow well over 100 lbs. They are one of the ultimate freshwater apex predators and will eat everything from grayling to ducklings. And they are a great indicator of watershed health. If a watershed has a thriving taimen population, it means that there is a healthy river food web with abundant prey fish and intact habitat.

Unfortunately, taimen are in decline across much of their range due to habitat loss and unsustainable fishing pressure. Harvest of taimen is a big cause of decline. They are attractive targets because they are so large. But they are actually pretty slow growing and don’t reproduce until they are relatively old. As a result, they just can’t handle much harvest pressure. As an apex predator, they also rely on healthy prey populations. Impacts to the prey base will also impact taimen.

So, we are working to raise awareness about taimen conservation, promoting catch-and-release as an alternative to taimen harvest by recreational anglers, and helping others to protect taimen habitat through protected area designation and sound land-use practices and education. We also conduct research on food webs that support taimen and we develop population monitoring tools that help inform decision making and policies that affect taimen watersheds.

Tugur River taimen.

Flylords: What exactly is a taimen for someone who may not be familiar with them?

Matt: Taimen are some of the largest and most ancient members of the trout and salmon family. There are actually five species of taimen, all found in Eurasia.

The most common and widespread species is the Siberian taimen (their Latin name is Hucho taimen). These are the taimen of Mongolia and the Russian Far East that you are most likely to see featured in fly fishing magazines.

There is also the huchen or “Danube salmon” (Hucho hucho) that is native to the Danube River system of Eastern Europe.

Sakhalin taimen, Koppi River, Russia.

Then there is the Sakhalin taimen (Parahucho perryi), which you can see pictured above. They are native to Russia’s Sakhalin Island and a few coastal mainland watersheds like the Koppi River, and also Japan’s Hokkaido Island.

China’s Yangtze River system is home to another taimen species, the Sichuan taimen (Hucho bleekeri).

And finally, there is the Korean taimen (Hucho ishikawae), hopefully still swimming somewhere above the DMZ in the borderlands of North Korea and China. Very little is known about this species.

All of these species are voracious freshwater predators. Sakhalin taimen are the only anadromous taimen species, undergoing seasonal migrations out into the salt, but generally staying nearshore. Siberian taimen make extensive migrations in freshwater, but they are not known to enter saltwater even though they inhabit rivers draining to the Arctic and Pacific Ocean.

Flylords: Where is their range?

Matt: Taimen are native to Eurasia. Their range is expansive, encompassing around one-eighth of the land area of the Earth. Siberian taimen have by far the broadest distribution of all taimen extending across nearly all of northern Russia, Kazakhstan, Mongolia, and parts of China. The other taimen species are much rarer and have smaller ranges. Check out the map below.

Here is a map of taimen distribution, courtesy of the Wild Salmon Center.

Flylords: How big do taimen get? 

Matt: Taimen get very big. Siberian taimen appear to have achieved the greatest size of any taimen species, although records are a little spotty. There are a couple of historical records of Siberian taimen in excess of 200 pounds caught in fishing nets in Russia, and several records of fish exceeding 175 pounds. There are also historical records of huchen and Sakahlin taimen exceeding 100 pounds. Sadly, there are widespread declines in body size across taimen species. However, Siberian taimen in excess of 100 pounds are definitely still out there in the healthiest remaining taimen watersheds.

Flylords: What do taimen eat?

Matt: Taimen start eating fish very early in life, once they get to be around 3 inches in length. From then on, fish comprise the majority of their diet. They are capable of eating other fish that are nearly half their length, and they seem to especially like grayling. As taimen get larger, they are able to eat a wider variety of prey. In Mongolia, they famously chow on mice and lemmings. In Russia, they’ve been known to eat muskrats and ducklings. There is even a report of a taimen that choked to death trying to eat a small dog! In our work in the Russian Far East, we’ve found that large taimen will eat adult chum salmon returning to rivers on their spawning migrations. In fact, salmon appear to be the primary prey for the largest taimen in some rivers.

The largest taimen eat adult chum salmon whole.

Flylords: Anything unique/cool about taimen?

Matt: There are so many unique/cool things about taimen. One of the coolest is that taimen hunt in packs, which has earned them the name “river wolves.” This is a pretty rare behavior for trout species, which are more commonly territorial feeders.

The biggest taimen can also swallow an adult salmon whole! A Russian guide told me that he had once caught and killed a large taimen (catch-and-release is a relatively new concept in Russia) and in its belly was a female chum salmon still bright and fresh enough that they ate the salmon caviar along with taimen steaks.

The other thing I think is cool about taimen is that you really only find them in amazing places. If you can travel to a taimen watershed, you are likely going to a pretty intact ecosystem with big predators on land and in the river. In Russia, for example, Sakhalin taimen watersheds are also home to Amur tigers, brown bears, Asiatic black bears, wolves, and Blakiston’s fish owls (as the largest owl in the world, it has a wing span up to 6 feet and it eats salmon). Last fall on a trip to Mongolia, we drove by Bactrian camels on the steppe, we saw brown bear tracks on the gravel bars along the river, and we awoke to howling wolves more than once. Taimen are amazing themselves, but for me a big part of their allure is that they perfectly encapsulate all of the wild that surrounds them.

Getting to the river, Mongolia.

Flylords: What are some of the goals of the work you are doing? 

Matt: The main goal of our taimen work is to help preserve the remaining healthy taimen watersheds in Russia and Mongolia. Siberian taimen are considered vulnerable to range-wide extinction by the International Union for the Conservation of Nature (IUCN) and they are extinct in parts of their historical range in Mongolia. Sakhalin taimen are critically endangered, as are Sichuan taimen. Danube taimen are considered endangered. And the status of Korean taimen is unknown. So as a group of species, taimen are in need of immediate conservation action to help stop them from edging towards extinction.

Navigating the upper Koppi River, Russia.

Currently, the work we are doing at Wild Salmon Center is focused on Siberian taimen in Russia and Mongolia and Sakhalin taimen in Russia. For these species, we provide support to local groups that are fighting for habitat protection, preventing taimen poaching, and we conduct applied conservation science to help track the status of populations. Over the last decade, our partners have succeeded in securing permanent protection for a number of critically important taimen watersheds. Through our research, we are also helping unlock the mysteries of taimen biology. There is still a lot to be learned about taimen reproduction, behavior, and life histories. For example, in Russia we are learning just how much taimen depend on healthy salmon populations for prey. Maintaining healthy taimen populations involves habitat protection and a solid prey base, which in this case means sustainable salmon management. We are taking these lessons to Mongolia to better understand the prey base needed to support those taimen populations, which don’t have salmon to feed on. This research can help managers make better decisions about taimen conservation.

Photo: Guido Rahr.

Flylords:  Some of the work you do requires catching taimen on the fly, can you walk us through the fly fishing setup you use to catch taimen?

Matt:  Fly fishing can be the most effective method of catching taimen for research projects in these remote watersheds where there is limited access and infrastructure. For example, in Russia access to healthy taimen watersheds generally requires a lengthy helicopter flight, so gear is limited to the basics, the rivers are big and full of logs, so sampling gear like nets and seines are pretty ineffective. So, we tend to rely on fly fishing to capture taimen.

My typical set up in Russia is a two-handed 13-foot 10-weight, rigged with 30-foot shooting heads ranging from floating to very fast sinking, followed by 50 pound mono running line. I use a large arbor reel with a decent sealed drag. I usually run 30 or 40-pound test Maxima leader. The flies are typically 6 to 10-inch unweighted streamers tied on tubes. Taimen seem to love to eat grayling, so a go-to streamer is one like Guido’s Grayling that matches the gray and yellow of the common grayling species in Russia. But there are conditions where gaudy streamers in black and red, chartreuse, or bright orange are more effective, especially in higher water when water clarity is not ideal. There are also situations where taimen are pretty surface-oriented when I’ll throw a big foam popper in front of the streamer and fish on top.

Guido’s grayling tube fly and a 3/0 siwash hook bent sideways by a 101 lb taimen.

It’s important to emphasize that my setup primarily serves a research goal of trying to get the most fish to the net as quickly as possible so that we are efficient with field data collection and also minimizing impacts on the fish. It is not necessarily fun to cast this setup all week, especially when taimen encounters are few and far between. If I wasn’t fishing for research I might switch it up a little. For example, as I learn more about taimen and taimen fishing, my setup is evolving somewhat to be a little lighter and more surface-oriented, which I’m hoping will be as effective and cause a little less shoulder pain!

Photo: Guido Rahr.

Flylords:  What is the biggest taimen you have caught? 

Matt: During a fall 2018 research trip to Russia’s Tugur River, I landed a 101 lb Siberian taimen while fly fishing. On the last day of a week-long trip, I was fishing out of a johnboat in an area where several shallow river braids came together and deepened into maybe an eight-foot trough– a perfect ambush spot for a predator. The water had been higher than normal and we had struggled to find fish all week. But finally, the water had dropped into shape. I was fishing a 6-inch Guido’s Grayling streamer (that Guido Rahr tied that morning and generously gave to me for good luck). I was stripping the fly when it just stopped like I had hooked a log. And then the log started moving, then head shakes, then a surface explosion that let us know we had a serious fish. Twenty minutes of near chaos ensued until we netted the fish and realized we had a truly exceptional taimen.

Photo: Guido Rahr.

Because this was part of a research effort, we discovered from subsequent analysis of scale samples, that the fish is male, was 32 years old when it was captured, and it had been feeding primarily on salmon. Encountering taimen this big is a sign of a very healthy ecosystem- a testament to the pristine habitat conditions and healthy salmon runs of the Tugur.

Photo: Guido Rahr.

Flylords:  It looks like National Geographic has named you a “National Geographic Explorer,” can you talk a little bit about how this has supported some of the work you have been doing?

Matt: In 2018, National Geographic really boosted our efforts for taimen research and conservation in the Russian Far East with a multi-year Explorers grant. Their support has helped move the needle on our work with local partners to secure watershed protected areas in Siberian and Sakhalin taimen strongholds. It has also helped raise awareness about the conservation threats facing taimen across their range. Given their massive profile, we hope that this is the beginning of sustained engagement with National Geographic in our efforts to help safeguard a future for these amazing fish.

Flylords: Have you had any scary encounters with wildlife, people, etc when you have been on assignment? What are some of the challenges of traveling to these remote places?

Matt: We work in remote salmon watersheds that also support tigers, wolves, mountain lions, and bears. It’s an adventure for sure. Often there are planes, helicopters, jet boats. We always prepare carefully and use a healthy dose of caution anytime we’re in wild country. I’ve been an arms-length from brown bears in Alaska (much too close!), but thankfully I have never had a bad encounter with wildlife.

Heading out in a MI-8 helicopter for a Russian taimen expedition.

The main challenge of this kind of remote work is to remain flexible and roll with the punches. We get weathered in at times when flying is just not an option, or extracted earlier than expected when the weather is deteriorating. Research trips we plan ahead for months are called off when rivers blow out. It can be frustrating. You’ve waited for this big trip, you’re on the last leg of travel but the weather’s falling apart– it’s tempting to push the margins. But a lot of accidents happen when you are in a rush or trying to push the conditions too much– flying in marginal weather, for example. There are so many elements beyond your control, you have to carefully manage the risks that you can control by making good judgments.

Taimen Country.

Flylords:  Does the future look good for taimen? Will our children and grandchildren be able to encounter these fish? 

Matt: I believe there is a strong future for taimen, but not without sustained conservation efforts. Humans present the biggest threat to taimen, through harvest, impacts on their prey, and habitat degradation. It is no coincidence that the healthiest taimen strongholds tend to be very remote and difficult for people to access. Proactive watershed protection in these places can provide some much-needed limits on potentially harmful resource extraction and will help safeguard taimen for future generations. The hope for taimen in more accessible watersheds depends on applied science and education and the support of local communities.

Sloat’s first Mongolian taimen with Tulga Tumenjargal, Mongolia River Outfitters.

Our research and that of others help us understand what makes healthy taimen populations tick. It provides the foundation for responsible decision making by identifying types of development that pose the greatest risk for taimen and those that are less likely to have an impact on taimen. Grassroots education in local communities is also a key component for growing the next generation of taimen advocates. At the end of the day, local communities also need to see that healthy taimen rivers have value, that taimen are worth more in the river than if they are harvested. This means providing incentives for conservation, like those provided by conservation-oriented angling programs. We are fortunate to work with many dedicated and effective Russian and Mongolian conservation partners. They inspire me to believe that my kids and grandkids will also have the opportunity to encounter these amazing fish.

Ovoo prayer flags in the land of steppe and sky.

Flylords:  What can we as anglers do to support the taimen and the work that you are doing?

Matt: I think there is a very important role for anglers in taimen conservation. Since taimen are not a commercially harvested species, having other economic incentives to support taimen conservation is critical. Catch-and-release fly fishing is a great form of ecotourism that can bring resources to rural communities and demonstrate the very tangible value of healthy taimen rivers. Anglers can book a trip with one of the outfitters that gives a portion of the trip fee towards taimen conservation. Anglers can also donate directly to organizations like Wild Salmon Center that have a proven track record of effective taimen conservation efforts.

Sloat’s first Mongolian taimen with Tulga Tumenjargal, Mongolia River Outfitters.

Flylords:  Can just anyone book a destination fly fishing trip to catch a taimen on the fly?

Matt: Yes, there are outfitters in Russia and Mongolia that offer guided fly fishing for Siberian taimen. Several of them, like Konin Lodge on Russia’s Tugur River, are deeply engaged in protecting taimen. It is always a good idea to do your research and go with a reputable outfitter. A trip to Mongolia may be the most accessible Siberian taimen trip for most western anglers. We work closely with Mongolia River Outfitters and Fish Mongolia to integrate taimen conservation and science into their fly fishing trips. These groups and others have been working in Mongolia for decades to protect healthy taimen watersheds and they offer a world-class angling and cultural experience.

Thank you Matt for taking the time to educate us about Taimen and your experiences with them. To follow along with Matt, check him out on Instagram at @wildsalmonscience and be sure to check out all the awesome work the Wild Salmon Center is doing here:

Nonprofit of the Month: The Wild Salmon Center

Behind the Fish: Steelhead/Salmon Biology with Scientist John McMillan



  1. Goo Vogt, Rene Limeres and myself were trying to raise conservation awareness of taimen in the early 90s. Goo pioneered fishing for taimen and held the first IGFA world record and put the Tugur on the map so to speak. We taught the Russians how to release them, and endeavored to convince them what a special fish it is. It was (probably still is) very prestigious to kill and eat taimen, especially for celebrations like weddings. Congratulations Matt (and Guido) on breaking the 100 lb mark. We knew after fishing the Tugur several times back in the day that fish was there, we caught some nice fish, straightened some hooks and the cult set in. I tip my hat to your success, and hope for a future with Hucho taimen on the planet. Thanks!

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