Reproductive biology of amur flathead asp Pseudaspius leptocephalus (Pallas, 1776)

Abstract

Some characteristics of reproductive biology are considered for amur flathead asp Pseudaspius leptocephalus (Pallas, 1776), as features of its spawning, reproduction capability, annual dynamics of oocyte growth and females gonadosomatic index. This is the species with a single batch spawning. Age of maturity for the asps living in different areas ranges from 3+ to 5+, mostly 5+ with the body length of 31 cm for the key fishing grounds. They spawn in the lower sections of mountain rivers from late May till early June. Females prevail in ratio 2 : 1, on average, both in the spawning and feeding aggregations. The individual absolute fecundity of amur flathead asp females depends linearly on their body length and weight.