Fish community structure in the Dnipro-Orilskiy Nature Reserve, Ukraine (1987–2015)

Study Extent

The study was conducted within the boundaries of the Dnipro-Orilskiy Nature Reserve in south-central Ukraine, specifically in the floodplain sections of the Dnipro River and its associated water bodies. Monitoring took place annually during the summer months from 1987 to 2015. The sampling covered shallow littoral habitats across multiple permanent stations to assess spatial and temporal dynamics of young-of-the-year fish communities under natural reserve conditions.

Sampling

Fish were sampled annually using a 15×2 m beach seine with a 3 mm mesh size. Sampling was conducted in the littoral zone during the summer period (June–August), targeting juvenile fish (young-of-the-year). Each haul covered an area ranging from 50 to 300 m². At each sampling station, all captured individuals were identified to species level and counted. The sampling effort was standardized across years and locations to allow for interannual comparisons of community structure. No fish were retained; all individuals were released after data collection.

Quality Control

All fish specimens were identified to species level by experienced ichthyologists using standard taxonomic keys. Data validation included cross-checking of species names with current taxonomic databases (e.g., FishBase, Catalogue of Life). Data entry was verified manually to avoid transcription errors. Geographic coordinates and dates were checked for consistency across years. Only verified and complete records were included in the final dataset.

Method steps

1. Field sampling was conducted annually from 1987 to 2015 using a 15×2 m beach seine (3 mm mesh) in the littoral zone of the Dnipro-Orilskiy Nature Reserve. All collected juvenile fish were identified to species level on site or in laboratory conditions using standard taxonomic keys. For each haul, location (GPS), date, and sampling effort (area covered) were recorded. Species presence and abundance data were entered into a structured database and cross-checked for consistency. Taxonomic names were validated using FishBase and Catalogue of Life. Cleaned occurrence data were exported to Darwin Core format for GBIF publication.

The dataset includes freshwater fish species primarily from the class Actinopterygii (ray-finned fishes), representing multiple families such as Cyprinidae, Percidae, Gobiidae, and Esocidae. All species recorded are native or naturalized in the Dnipro River system. The dataset focuses on young-of-the-year (YOY) individuals, providing insights into the recruitment and early life stage dynamics of fish communities. The taxonomic identifications follow FishBase and national checklists of Ukrainian ichthyofauna.

1. Actinopterygii
   common name: Ray-finned fishes rank: class
2. Cyprinidae
   common name: Carps and minnows rank: family
3. Percidae
   common name: Perches rank: family
4. Esocidae
   common name: Pikes rank: family
5. Gobiidae
   common name: Gobies rank: family

The dataset covers the aquatic habitats of the Dnipro-Orilskiy Nature Reserve, located in the floodplain region of the Dnipro River in central Ukraine. The reserve includes a mosaic of rivers, oxbow lakes, floodplain ponds, and channels that provide essential spawning and nursery grounds for freshwater fish. All sampling sites were situated within the protected area boundaries in the Dnipropetrovsk region, between the left bank of the Dnipro River and the Oril River delta.