Sakhalin TaimenNews & Program Updates
A closer look at one of the Pacific's largest and most ancient salmon species
Sakhalin taimen (Parahucho perryi, also known as Hucho perryi) is an ancient species, which can live up to 30 years and reach 2 meters (6 feet) in length and over 50 kilograms (100 pounds) in mass. The largest salmonid in the world, taimen occupy a globally unique ecological niche. Known as the 'river wolf', its diet can include mammals, ducklings, and large fish, including possibly returning adult salmon. The species faces an uncertain future in its native habitat on the Japanese Island of Hokkaido, Russia's Sakhalin and Kuril Islands and far eastern mainland Russia. Taimen have a long, complex life-cycle and are dependent on freshwater, estuarine and marine habitats. Due to overfishing and land use development, over 90% of Sakhalin taimen's historic abundance has been lost. The International Union for Conservation of Nature (IUCN) has listed the taimen as a critically endangered species, the core distribution and abundance of which remains centered on Sakhalin Island.
Taimen 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 our rivers and oceans. Due to their small population size and the complexity of their life cycle, however, taimen have been poorly studied and major gaps in our understanding handicap our efforts to ensure the long-term survival of the species.
Since 2005, WSC has worked with the IUCN Salmonid Specialist Group and our partners in Japan and the Russian Far East to fill this gap in our understanding of this enigmatic species. Our research efforts have been focused in three separate areas: 1) understanding extinction risk and describing ecological and genetic differences among a group of key river populations within their natural range, 2) describing migration and life history patterns, and 3) 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.
An important component of our research efforts were highlighted in a recent scientific paper describing Sakhalin taimen extinction risk. The paper describes the environmental factors that have shaped their historical global distribution and identifies key watershed characteristics that are associated with stable taimen populations. The study concludes that the species is range-restricted due to preference for intermediate levels of precipitation, a requirement for cold temperatures, and minimally developed agricultural land use. In addition, the authors identify the crucial role that intact, low gradient river floodplains play in conserving this species. In particular, large lagoons appear to serve as critical overwintering habitat for this species.
Since the listing of the species by IUCN in 2006, we have reached a number of important conservation milestones to ensure their protection:
- Creation of the Sarufutsu Conservation Forest
- Creation of the Koppi River Preserve
- Establishment of more restrictive fishing regulations in Hokkaido (Act of the Conservation of Threatened Species, passed by the Hokkaido Government) to limit fishing pressure on the species in the Shiribetsu, Shari and Kushirio Rivers
Armed with emerging knowledge from our field and laboratory research efforts, WSC is leading efforts to conserve critical habitat for taimen. We are also working 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 a critically endangered, flagship species, and make a lasting contribution to the health of Asia's remarkable wild salmon ecosystems.
- IUCN Red List of Threatened Species, Sakhalin taimen assessment
- Reconstructing Sakhalin Taimen Historical Distribution and Identifying Causes for Local Extinction (Fukushima et al., 2011)
- Ancient, giant salmon in Asia edging towards extinction
- Notes from the Field: Tracking Giants in Japan's Sarufutsu River
- Notes from the Field: Monitoring Taimen in the Russian Far East Koppi River