Morphological characteristics and biological peculiarities of the flathead asp Pseudaspius leptocephalus from the northwestern Sakhalin waterbodies
New data on systematics and biology of the flathead asp Pseudaspius leptocephalus from northwestern Sakhalin water bodies were obtained based both on the results of SakhGu research expedition 1993-2003 and SakhNIRO expedition 2010. On Sakhalin Island, flathead asp distributed over the northwestern part (lakes Sladkoye and Patanki, rivers Langry and Chingai). In Lake Sladkoye during researches 2010, the flathead asp was revealed over the whole coastal area. This species formed the largest aggregations in the northern part of the lake preferring the open coastal sites not far from the water plant thickets. The paper presents a mo rp ho metric characteristic of fish from Lake Sladkoye. The comparative analysis of flathead asp sampled from Sladkoye Lake and from Orel Lake showed their similarity through 21 characters. The flathead asp from our catches in 2010 was represented by specimens of 3 to 6 years old. Their length varied from 15.6 to 35.2 cm (average 28.5±0.74 cm), weight from 44.2 to 607 g (average 320.4±21.01 g). Their growth increment in the first year of life was 6.3 to 11.9, average 9.0 cm. With the increase in age in different age groups, the rate of growth slowed significantly. Despite a rather wide distribution, commercial importance of flathead asp is not great. This species is an object for sports fishing in Sakhalin inland water bodies.