Fish occurrence in the Kuban River Basin (Russia)

Abstract Background This publication describes a dataset containing information on 1328 occurrences of fishes in the Kuban River Basin, the longest river of Northern Caucasus and representing its own freshwater ecoregion (428 Kuban Ecoregion). All observations have precise geo-referencing with the names of water bodies (rivers, lakes etc.). The dataset is based on both literature data (509 occurrences) and our own sampling (814 occurrences). Observations were carried out between 1889 and 2020. New information The majority (> 61%) of occurrences in the presented data are published for the first time. This extended dataset contributes significantly to fish fauna survey in the Kuban River ecoregion.

The Middle Kuban River is considered an important place for the conservation of freshwater fishes in the Caucasus (Freyhof et al. 2020). The Kuban Basin is a separate ecoregion (428 in Abell et al. 2008), fish fauna of which is distinct from other ecoregions of the Caucasus. The native fauna is also clearly distinct from that of Don (ecoregion 427), which is geographically close, but has a different geological history (Bogutskaya and Hales 2021). In addition to new occurrence records, the dataset presented contains information on the type localities of the endemic species with data on museum numbers of type specimens. The basin of the Kuban River is located in Northern Caucasus, a highly populated region with developed agriculture. High anthropogenic activity resulted in numerous alien fish invasions, some of which are now naturalised.  (Moskul 1998, Moskul et al. 2012. The fish fauna of the Kuban Basin has been studied for a long time (e.g. Aleksandrov 1927, Berg 1949, Sukhanova and Troitskiy 1949, Tamanskaya and Troitskiy 1957, Troitskiy and Tsunikova 1988, but few publications contained data for certain localities. The goal of the study was to collect comprehensive data on occurrences of the Kuban fish species and to make these data available using GBIF (Artaev et al. 2021). The information on species distributions can be used by ichthyologists, ecologists, conservation biologists and managers of areas of nature protection.

Sampling methods
Study extent: The dataset contains information on 1328 occurrence records (one species in a definite place at a definite time) of 63 taxa, 58 of which were identified at species level, while six taxa were identified at generic level. The occurrences were recorded between 1889 and 2020. The study area is ~ 57900 km . Photographs of some endemic fish species of the Kuban Basin: A Alburnoides kubanicus (Kudako River); B Barbus kubanicus (Ubin River); С Petroleuciscus aphipsi (Il' River). Scale bar -1 cm. Photographs by Oleg Artaev.
Fish occurrence in the Kuban River Basin (Russia) Quality control: Each observation contains fundamental information, such as locality (coordinates), date, name of water body, name of observer and name of identifier. Geographical latitude/longitude coordinates for the majority of localities were obtained using hand-held GPS devices, while coordinates for localities extracted from literature and those missing coordinates were determined using the Google Maps service. Species were identified, based on morphological characters (Berg 1949, Bogutskaya and Poznyak 1994, Naseka and Bogutskaya 1998, Naseka and Freyhof 2004, Vasil'eva et al. 2004).
Step description: First, we analysed published data on fish records. Second, we added our data on fish occurrences.

Geographic coverage
Description: All occurrences were recorded within the Kuban River Basin which drains the North-western Caucasus and discharges into the Azov Sea and within the Large Stavropol' irrigation canal draining the the eastern part of the Kuban Basin and parts of the Kuma and Terek Rivers (both belong to Caspian Sea drainage - Fig. 2; the three most eastern localities out of the Kuban Basin belong to the Large Stavropol irrigation canal) and the upper part of Stavropol' canal discharging waters to the Manych-Don system. The length of the Kuban River is 870 km and watershed area is ca. 57900 km . The Basin can be subdivided into three geographical zones: highlands, submontane and lowlands. The main drainage area is the northern slopes of the Caucasus with 2600 mm precipitation (Kupriyanov 1973). Lower reaches of the Kuban are located in agricultural landscapes and a significant volume of the Kuban water is taken for irrigation. There is one reservoir on the Kuban River, the Krasnodar Reservoir, located in its lower reach. This is the largest reservoir in the Northern Caucasus. It was built at 1973 with an area around 400 km ; its length is 46 km and 8-11 km wide (Pogorelov and Laguta 2019). Climate is mild in the middle and lower reaches of Kuban Basin with sub-zero daily temperature only during December-March (Kupriyanov 1973

Taxonomic coverage
Description: The dataset contains information on 63 taxa, of which 57 were identified at the species level and six at the genus level (Table 1). The species detected belong to 47 genera, 18 families and two classes. A few taxa need further commentaries on their taxonomic status. Individuals identified as Rutilus rutilus (Linnaeus, 1758) were replaced by R. lacustris (Pallas, 1814) according to results from genetic studies (Levin et al. 2017, Artaev et al. 2021. For a long time, the Kuban was thought to be home to only one Barbus species, endemic to the Kuban system, B. kubanicus. A recent genetic study (Levin et al. 2019) revealed that the upper reach of the Abin River, a left tributary of the Kuban River, is additionally inhabited by B. tauricus with hybridisation observed between these Barbus spp. The connection of the Kuban system with the Kuma and Terek riverine systems via the Large Stavropol' irrigation canal, as well as with the Manych-Don system via the Nevinnomysk irrigation canal, may facilitate exchange of fish fauna as exemplified by B. kubanicus occurrences in the Manych system (Poznyak 1987). We consider the Prussian carp as Carassius auratus (Linnaeus 1758) species complex since its taxonomic status is still under debate (Wouters et al. 2012, Rylková et al. 2013, Vekhov 2013, Šimková et al. 2015.

Column label Column description
occurrenceID The Globally Unique Identifier number for the recored. basisOfRecord The specific nature of the data record: HumanObservation. eventDate date format as YYYY-MM-DD. scientificName The full scientific name including the genus name and the lowest level of taxonomic rank with the authority. kingdom The full scientific name of the kingdom in which the taxon is classified. phylum The full scientific name of the phylum or division in which the taxon is classified. class The full scientific name of the class in which the taxon is classified. order The full scientific name of the order in which the taxon is classified. family The full scientific name of the family in which the taxon is classified. decimalLatitude The geographic latitude of location in decimal degrees. decimalLongitude The geographic longitude of location in decimal degrees.

Country
The name of the country (Russia).
countryCode The standard code for the country in which the Location occurs. individualCount The number of individuals represented present at the time of the Occurrence. year Year of the event was recorded. Fish occurrence in the Kuban River Basin (Russia) identificationRemarks Comments or notes about the Identification -what Latin name was given when describing a species from this locality.

institutionCode
The name (or acronym) in use by the institution having custody of the object(s) or information referred to in the record. geodeticDatum The ellipsoid, geodetic datum or spatial reference system (SRS) upon which the geographic coordinates given in decimalLatitude and decimalLongitude are based.
identificationQualifier A brief phrase or a standard term ("cf.", "aff.") to express the determiner's doubts about the Identification. taxonRank The taxonomic rank of the most specific name in the scientificName.
taxonRemarks Comments or notes about the taxon or name.