To the biology of the Prussian carp Carassius gibelio (Bloch, 1782) in the Middle Ob river basin

Abstract

Information about some features of the Prussian carp Carassius gibelio (Bloch, 1782) in three different floodplain lakes in the Middle Ob river basin are presented. Individuals of younger age groups predominate in populations. Fish over the age of 9+ are not noted. The ratio of females to males is different, from 4:1 to 8:1, always in favor of females, which is typical for Prussian carp populations in Western Siberia. There were specimens in the sample from 152 to 355 mm long and weighing from 115 to 1250 g. When comparing males and females of the same age, the latter are generally larger. The noted size characteristics — 335 mm and 1250 g — are the maximum of the published data for Prussian carp Carassius gibelio in the Middle Ob river basin. When comparing individuals of the same age, it was shown that Prussian carp Carassius gibelio is a larger size in the big not-frozen lake Monatka than in the small, frozen lakes Zmeevo and Taskino. The maturity of female Prussian carp Carassius gibelio in floodplain lakes of the Middle Ob river basin occurs at the age of 3+, but some 2+ were mature. At the age of 4+, all specimens in the samples were sexually mature. Sexual dimorphism Prussian carp from lake Monatka is weakly expressed: in males, the length of the head, the height of the dorsal and the length of the pectoral fins are statistically significantly greater. A higher dorsal fin can be considered a characteristic feature of the male Prussian carp in the south of Western Siberia in comparison with the females.