Taimen (Hucho hucho taimen) are the world’s largest salmonid, historically reaching lengths of 6.5 feet and weighing as much as 200 pounds. This unique fish is incredibly slow growing, long lived (up to 40 years), and late in terms of reaching sexual maturity (5-7 years). Taimen are apex predators, existing on a scale different from nearly all other freshwater species. Most scientists estimate that the healthiest Mongolian rivers contain no more than twenty adult taimen per kilometer. If one considers that these same stretches of river likely hold hundreds or thousands of lenok and grayling, that constitutes a very low population density. Giant trophy taimen over fifty inches are even more widely dispersed. Only a handful of these great fish inhabit even the best of taimen rivers.


Taimen are an extremely sensitive species and not easy to protect. Taimen once inhabited regions from Hokkaido to the Danube. Wild populations are now reduced to a few isolated pockets in remote places like Mongolia. Without aggressive conservation action supported by the international angling community, these remaining pockets of wild taimen will be lost.

Taimen are negatively impacted by harvest and changes in water quality. Taimen need vast stretches of pristine water to survive. An adult taimen may utilize over sixty miles (one-hundred kilometers) of river during a single season, moving from its respective spawning, summer, and winter habitats.

Taimen populations in Mongolia are threatened by poaching, habitat loss from mining, overgrazing, other development activities, as well as unsustainable recreational fishing practices. Biological characteristics coupled with overuse and habitat loss have resulted in a drastic species decline throughout its native habitat. In Mongolia alone, taimen have lost 19.1% of their native range and distribution (Hogan et al., IUCN Red Listing 2012). In 2012, Siberian taimen were for the first time listed on the IUCN Red List of Threatened Species. It has been determined that a 50% loss in overall species abundance occurred over the past three generations in Mongolia (Hogan et al., IUCN Red Listing 2012).

One would think that the difficulty associated with accessing these taimen populations would deter legal and illegal anglers. Unfortunately, that is not the case. It does, however, render enforcement extremely difficult.

Conservation Efforts

To combat the lack of enforcement, Mongolian outfitters have invested time and resources into sustainable catch-and-release taimen fisheries, and have implemented comprehensive, place-based conservation projects with local and national partners. Responsible Mongolian fly-fishing companies now measure their business success by how well they are able to protect taimen and taimen habitat. Conservation partnerships between fly-fishing outfitters and local communities generate community-based incentives for conservation, including jobs, investments and government revenue. People living closest to the river now actively support conservation and act as “river keepers,” protecting their taimen and rivers from harm. Fly-fishing companies, government agencies, communities, and the scientific community work together to conduct world-class research to build knowledge and awareness designed to secure the long-term survival of taimen.

There is much left to accomplish and many more Mongolian rivers to protect. However, successes to date prove that responsible and ethical “catch-and-release” fly fishing for taimen can lead to increased numbers of fish, protected watersheds as well as economic improvements for rural Mongolia.