The size and age composition of roach Rutilus rutilus (L.) at the upper part of the Kuibyshev reservoir Volga reach

Abstract

© 2016,International Journal of Pharmacy and Technology. All rights reserved.The size-and-age structure as well as indexes of the linear roach growth of the Volga upper reach of the Kuibyshev reservoir during 2010-2014 are considered. Material was gathered during control fishery with stationary nets. It is established that in the catch female small fries prevailed. Low level of average length indexes and the relative simplified nature of age structure around research reflect instability of population reproduction and high level of fishing pressure. The reconstructed indicators of the linear growth of roach on materials 2013 and 2014 years were substantially lower,both on different sites of the Kuibyshev reservoir,and on materials concerning the Volga River before the reservoir foundation. It is the result of the deterioration tendency continuation in roach growth in the Volga reach revealed earlier