About the natural reproduction of the fluvial anadromous and some river fishes in the lower reaches of the Volga river in 2011–2015
2017
Taradina, T.G. | Chavychalova, N.I.
The article presents the data of studies for the natural reproduction of roach Rutilus rutilus caspicus, bream Abramis brama, carp Cyprinus carpio, pike perch Stizostedion lucioperca, silver bream Blicca bjoekna, Prussian carp Carassius auratus gibelio, perch Perca fluvialitis, red-eye Scardinius erythrophtalmus and zope Abramis ballerus . There is number comparison of yang fishes in different periods . The work presents terms and considers the conditions of a spawning of spawners of these fish species . The article analysis the conditions of fattening of theirs fish juveniles and changes of its total number on the spawning grounds in the lower reaches of the Volga River at different water content of floods in 2011–2015 . It is shown that only in 2013 the conditions of the natural reproduction of the natural reproduction were corresponded to the requirements of the fishery to the object of spring floods in the Delta of the Volga River . The result of this was an extremely low yield of roach, and in recent years — bream . In conditions of low water content and reducing of flood period and fattening of fish juveniles, the size-weight indicators of all juveniles are become worse, the number of fishes is reduces, that at the end have an impact on the value of theirs breed . The adverse conditions for the reproduction of fishes, which are formed in the period under review, have negatively effect on the effectiveness of their reproduction . The lowest number of all fluvial anadromous and river fishes as well as perch, crucian carp and zope was noted in 2015 .
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