Spawning behaviour of taimen (Hucho taimen) from the Uur River, Northern Mongolia Manu Esteve & David Gilroy & Deborah Ann McLennan Received: 30 December 2007 / Accepted: 20 June 2008 / Published online: 29 August 2008 # Springer Science + Business Media B.V. 2008 Abstract This study presents the first observations of Hucho taimen spawning in the wild based on underwater video recordings. One pair of taimen was monitored during a 19 h period, supplemented with visual observations from two other spawning pairs. We recorded two full spawning events performed in two different locations separated by approximately 30 m. The absence of an established male hierarchy along a nesting female was the most important dif- ference between taimen and other salmonine breeding biology. Taimen spawning, based on our observations, is a single pair event. The male prevented the approach of other males by launching intense attacks that extended for several meters away from the redd. Our data suggests that taimen females, differently from other salmonines, do not cover their eggs immediately after having spawned but rest for a variable number of minutes before covering them. Keywords Hucho taimen . Underwater video . Spawning act . Salmonines Introduction The taimen (Hucho taimen) is a freshwater salmo- nid inhabiting rivers throughout Siberia and northern Mongolia. Practically all of the information on taimen ecology is published in journals that are not readily available to the western scientific community (Matveyev et al. 1998), and no papers exist in English describ- ing spawning based on first-hand observations. Even the impressive book by Holcˇík et al. (1988), which concentrates on the taimen’ s sister species huchen (Hucho hucho), only cites Russian papers for a few taimen spawning behaviours, making it difficult to verify the descriptions (Pravdin 1949; Bukirev 1967; Misharin and Shutilo 1971; Sigunov 1972; Kifa 1974; Olifer 1977). A summary of what we currently know about taimen spawning is as follows (based on Holcˇík et al. 1988): In spring, normally coinciding with thaw- ing, taimen migrate from larger, deeper rivers to smaller, shallower streams looking for clean gravely substrates with the right hydrological conditions. Females prepare redds, elliptical depressions with the longer axis along the stream line, in which they build nests to deposit their eggs. At least one major dif- ference in the spawning ecology separates huchen and taimen from the rest of the salmonines: timing of pair Environ Biol Fish (2009) 84:185–189 DOI 10.1007/s10641-008-9407-x M. Esteve (*) : D. A. McLennan Department of Ecology and Evolutionary Biology, University of Toronto, 25 Harbord St, Toronto, ON M5S 3G5, Canada e-mail: manuesteve@zoo.utoronto.ca D. Gilroy Center for Limnology, University of Wisconsin, 680 N Park Street, Madison, WI 53706, USA