The biology of stone loach Barbatula barbatulus in the Rivers Goloustnaya and Olkha, East Siberia

Five hundred and four stone loach 63–202 mm in total length, of I + to 8 + age groups, were sampled in two rivers of East Siberia from April to October 1989–90. This paper presents data on the seasonal dynamics of fecundity, ripening, fatness and feeding intensity. A second spawning from the end of August to October has been identified for the first time for this species. The absolute fecundity ranged from 1710 to 27600, and the relative fecundity varied from 216 to 833 eggs g⁻¹: (fish weight). Stone loach in the River Olkha grew faster than those in the River Goloustnaya and, according to this index, are closer to stone loach from streams of northern England.