Study of vertical distribution of zooplankton in Zaporozhskoye Reservoir aiming to calculate bighead carp stocking
| Autor: | V. A. Yakovenko, E. Yu. Zaychenko |
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| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: | |
| Zdroj: | Морской биологический журнал, Vol 3, Iss 3 (2018) |
| ISSN: | 2499-9776 2499-9768 |
| Popis: | The article focuses on the vertical distribution of zooplankton because of its importance for calculation of bighead carp stocking the Zaporozhskoye Reservoir. The reservoir is a water-body of complex use with fish catching being one of the priorities of the reservoir. Zooplankton is an important component of fish forage base, so accurate quantitation of zooplankton development is necessary for improving efficiency of forage base use of the reservoir by means of appropriate stocking with fish. These indicators depend significantly on the depth of the reservoir and can vary through the vertical section. At the same time, almost all investigations of the reservoir were aimed at studying the indicators of zooplankton development in the surface layer which can led to inaccurate calculations concerning the stocking of the reservoir with planktivorous fish. Therefore, the purpose of this work was not only to study the vertical distribution of zooplankton of the Zaporozhskoye Reservoir, but also to calculate the zooplankton production and the corresponding rates of stocking the reservoir with bighead carp. In summer and autumn periods, the heterogeneous vertical distribution of zooplankton was found in both parts of the reservoir. In the upper part of the reservoir, the maximum values of zooplankton development were observed in the surface and near-bottom layers whereas in the lower part of the reservoir – in the surface layer and at the depth of 10 m. Since conditions of the upper part of the reservoir are unfavorable for bighead carp, and the estimated value of the stocking density (0.3 spec.·ha-1) is negligible, no stocking of this part of the reservoir with the indicated planktivorous fish is expected. When calculating the stocking based on the zooplankton production in the surface layer only, but not in the whole water column, almost double overvaluation obtained (excess would be 246.8 thousand specimens) would lead to economic losses because of the wasteful expenditure of stocked material due to a lack of food resources. For effective utilization of zooplankton as the food base it is advisable to stock the lower part of the reservoir with two-year-old bighead carps with the stocking density of 19.1 spec.·ha-1. |
| Databáze: | OpenAIRE |
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