Ecology of Siberian taimen Hucho taimen in the Lake Baikal Basin

Taimen Hucho taimen historically inhabited most tributaries and littoral ar eas of Lake Baikal, in south central Siberia, where they supported subsiste nce and commercial fisheries. Logging, pollution, and overfishing have caus ed dramatic population declines or local extinction of most stocks. Most of what is known about this species has been published in eastern journals an d therefore is not readily available to western scientists. New data collec ted during the 1980s and 1990s have been combined with other reports to pro vide an overview of the biology and life history of this species. Taimen ar e long-lived fish and can reach ages of 29 years and sizes rtp to 60 kg. po pulations can either be strictly riverine or anadromous. Adults from both l ife histories ascend rivers in spring to spawn and feed, and less extensive migrations occur in fall to prey on spawning omul (Coregonus autumnalis mi gratorius). Principal food items for age I and 2 taimen are macroinvertebra tes, but young taimen quickly become piscivorous at age 2 when they consume mainly black Baikal grayling (Thymallus arcticus baicalensis), and sculpin s (Paracottus kneri, Cottus kessleri). Males reach sexual maturity at ages 7 to 8 and later for females at ages 8 to 9. Average egg production per fem ale was about 22,000 eggs. parasite burdens are heavy but composed of few s pecies and mediated by prey items consumed. This fish is a highly-specializ ed predator and plays an indispensable role in the structure of fish commun ities in mountains and foothills. Taimen conservation in the Baikal region is impossible without adoption and implementation of a dedicated rehabilita tion program that includes the protection of remaining populations and habi tat, and possibly introduction of hatchery-reared fish in selected areas wh ere habitat remains, but parental stocks are low.