Transformation of the ichthyological complex of the Sholokhove Reservoir (Bazavluk River): retrospective and current state
Purpose. To assess the dynamics of changes in the state of the ichthyofauna of the Sholokhove Reservoir based on many years of ichthyological research (1966–2024). Methodology. The materials of ichthyological surveys on the Sholokhove Reservoir (Bazavluk River) for a long period (1966–2024) were...
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| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Institute of Fisheries
2025-06-01
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| Series: | Ribogospodarsʹka Nauka Ukraïni |
| Subjects: | |
| Online Access: | https://fsu.ua/index.php/en/2025/2-2025-72/2025-02-075-097-kobyakov |
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| Summary: | Purpose. To assess the dynamics of changes in the state of the ichthyofauna of the Sholokhove Reservoir based on many years of ichthyological research (1966–2024).
Methodology. The materials of ichthyological surveys on the Sholokhove Reservoir (Bazavluk River) for a long period (1966–2024) were analyzed. The materials of biological justifications of the Special Commercial Fisheries Regimes (SCFR) were used, as well as data from fishery statistics on the reservoir (2000–2019). Fish were caught by fine-mesh dipnet (25 catches, mesh size of 3 mm) in the nearshorel zone, as well as by commercial fishing gears – 8 net lifts (gill nets with mesh sizes of 40–110 mm, length 30 m and height 2.0–4.0 m). The catches of recreational fishermen were analyzed. The species and the nomenclature of the ichthyofauna were identified according to identification keys.
Findings. In 1966–2024, 30 species of fish belonging to 8 families were identified in the ichthyofauna of the Sholokhove Reservoir. The most numerous family is Cyprinidae – 15 species (50.0% of the total composition). Species diversity during the study period ranged from 15 species (1966–1969) to 26 (2007–2009). In the 2020s, the share of native species decreased, but the role of introduced, invasive species, and self-colonisers increased. New species were registered: sunbleak Leucaspius delineatus, sunfish Lepomis gibbosus (2023), knout (toad) goby Mesogobius batrachocephalus (2024). Sørensen’s species similarity indices were calculated.
The ichthyofauna includes 4 trophic groups, with the dominance of benthic predators – 15 species (50.0% of the species composition). A significant simplification of the diversity of trophic groups after 2009 is associated with the deterioration of the conditions for fish habitat and reproduction. Sixteen fish species are of commercial importance in the Sholokhove reservoir. Protected species are: ide (Red Book of Ukraine), two species are on the Red List of the Dnipropetrovsk region, eight are listed in the Bern Convention.
Originality. The study consists of a comprehensive analysis of changes in the ichthyofauna of the Sholokhove Reservoir on the Bazavluk River for the period 1966–2024. For the first time, data on the long-term dynamics of the species composition of the ichthyofauna have been systematized. New fish species have been identified, which indicates active invasive processes in the reservoir. A retrospective analysis of changes in fish species diversity over a long period has been carried out. A simplification of trophic relationships after 2009 has been established due to human impact and degradation of the water body.
Practical Value. The study provides a basis for the management of aquatic bioresources, biodiversity conservation and improvement of the ecological state of the Sholokhove Reservoir. The presence of species with protected status emphasizes the conservation value of the reservoir within the landscape reserve of national importance “Bazavluk Coastal and River Complex”. |
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| ISSN: | 2075-1508 2312-9581 |