Sarufutsu Taimen Pair in Northern Japan© Satoshi Adachi
Science

Taimen

Science

Taimen

The Pacific’s largest and most ancient salmon species

A group of ancient species that occupy a unique ecological niche, taimen are the largest salmonids in the world. Taimen can live up to 30 years and reach 6 feet in length and over 100 pounds in weight. Due to their voracious appetite and their place at the top of the food chain (some feed on ducklings and adult Pacific salmon), taimen are sometimes called “river wolves.”

Sakhalin taimen
Sakhalin taimen | © Mikhail Skopets

These species represent an important evolutionary legacy in the global family of salmon and trout. Taimen also serve as a bellwether for ecological change. Because taimen reach maturity later and live longer than other salmonids, they are more sensitive to changes in their environment and serve as an important indicator of the health of the great rivers of Asia and Europe.

Taimen face an uncertain future in their native habitat, which spans the Japanese Island of Hokkaido, Russia’s Sakhalin and Kuril Islands and far eastern mainland Russia, Mongolia, China, and the Korean peninsula. The International Union for Conservation of Nature (IUCN) consider taimen species status to range from vulnerable to critically endangered. However, due to their small population size and the complexity of their life cycle – they are dependent on freshwater, estuarine and marine habitats – taimen have been poorly studied until recently.

Threats

While a variety of threats to taimen exist, our first priority needs to be protecting critical freshwater habitat. That is the core of WSC’s work on taimen conservation.

IUCN Status

An important milestone was reached in 2012 with the completion of range-wide status assessment of all the species in the genera Hucho and Parahucho. These species were added to the IUCN Red List of Threatened Species, and the assessors concluded all taimen species were either Threatened or Data Deficient, underscoring the need to take immediate action to reverse declining trends observed throughout their range.

WSC’s Role

Sarufutsu taimen
Japanese research partner Dr. Michio Fukushima, releases a Sakhalin salmon into the Sarufutsu River in Hokkaido, Japan. | © Wild Salmon Center

WSC’s on-going work has focused on two species, Sakhalin and Siberian taimen (learn about each species below). In addition, we have established a strong, international network of specialists dedicated to work on the other species. To fill in the gaps in our understanding of these enigmatic species with the hopes of furthering their long-term survival, WSC is working with the IUCN Salmonid Specialist Group and partners in Japan, and the Russian Far East. These research efforts are focused on three separate areas:

  • Understanding extinction risk and describing ecological and genetic differences among a group of key river populations within their natural range.
  • Describing migration and life history patterns.
  • Carrying out river expeditions to identify key habitats (particularly spawning habitat) and developing methods to estimate adult population abundance to provide a baseline for our conservation work.

Armed with emerging knowledge from our field and laboratory research efforts, WSC is leading efforts to conserve critical habitat for taimen. We have also worked on educational initiatives, strengthening local watershed councils, and encouraging sustainable fishing practices to further advance taimen conservation. Our efforts are focused on northeast Sakhalin, which may support the largest river populations of the species. In addition to conserving critical habitat, we are also working on educational initiatives, strengthening local watershed councils, and encouraging sustainable fishing practices to further advance taimen conservation.

Through community involvement, education and science-based strategies to identify and protect taimen strongholds, we have an important opportunity to protect this critically endangered, flagship species, and to make a lasting contribution to the health of Asia’s remarkable wild salmon ecosystems.

Monitoring the Koppi River
Monitoring the Koppi River | © Pete Rand

Sakhalin Taimen

Initially grouped with all other taimen (Hucho), genetic studies have shown that Sakhalin taimen should be placed in their own genus (Parahucho). They are thought to be the only species of taimen that spends part of its life history in the ocean.

Sakhalin taimen, Japan
Spawning Sakhalin taimen in Japan’s Sarufutsu River | © Satoshi Adachi

For over 10 years we have been carrying out research and conservation work to conserve Sakhalin taimen (Parahucho perryi). An important component of our research efforts were highlighted in a scientific paper describing Sakhalin taimen extinction risk. The paper details environmental factors that shape their distribution and identifies key watershed characteristics that support stable taimen populations. The study concluded that the species prefers intermediate levels of precipitation, cold temperatures, and minimally developed agricultural land. In addition, the authors identified the crucial role that river floodplains play in conserving this species, especially large lagoons.

Dr. Pete Rand, formerly WSC’s Senior Conservation Biologist, conducted a two year study of the Sarufutsu River, a global stronghold for the species in Hokkaido, Japan as part of a Fullbright Fellowship. He recounted his experiences in this National Geographic Society blog post..

A range-wide status assessment for the species was completed in 2006 and concluded the species was Critically Endangered. Since that time we have maintained an active research program on these fish to help guide our conservation work (see our recent publication on the species extinction risk here).

Vostochny Wildlife Refuge, Sakhalin, Russia
Vostochny Wildlife Refuge | © Sakhalin Environment Watch

Much progress has been made on the conservation recommendations highlighted in the IUCN assessment, but the establishment of these protected areas is especially noteworthy:

  • Vostochny Refuge, Sakhalin, Russia.
  • Koppi River Preserve, Khabarovsk, Russia.
  • Sarufutsu Environmental Conservation Forest, Hokkaido, Japan.

These protected areas, amounting to more than 1,000 square kilometers (an area larger than the size of the Shenandoah National Park in the eastern United States), helps us secure the future of this threatened species. Sensitive riparian and floodplain habitat, increasingly under development threat, is now under permanent protection.

Siberian Taimen

Siberian taimen (Hucho taimen) have the broadest distribution of all taimen, and are recognized as the largest member in the group. Their range extends from the Ural Mountains in Europe to the Amur River in the Russian Far East, an area representing approximately one-tenth of the land area of the Earth. Despite this huge range, the species was assessed as Vulnerable by IUCN in 2012 based on evidence of a long-term decline in abundance, primarily a result of overfishing and illegal fishing practices.

Siberian taimen
A 122 centimeter (4 foot) Siberian taimen; human added for scale | © Clemens Ratschan

We have been working closely with our Russian partners to establish protected areas for this species in Khabarovsk, Russia, in the lower Amur River region. The Tugursky Nature Reserve protects nearly 80,000 acres of critical habitat in the Tugur Watershed. Populations of Siberian taimen in this region are unique because they are the only populations that feed on returning adult Pacific salmon.

In addition, we have also established stronger relations with research and conservation efforts focused on the species in Mongolia (maaeri.weebly.comwww.taimenfund.org).

We look forward to combining forces to develop a more integrated, international effort to conserve these river giants.

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