In recent years, pumpkinseed Lepomis gibbosus (Actinopterygii: Centrarchidae) have spread intensively to many parts of Europe, including Ukraine. In this study, we (1) assess intra-population genetic variability in five widely-spaced Ukrainian pumpkinseed populations and compare their population genetic structure with other European populations and (2) provide a comprehensive survey of pumpkinseed parasites across the region. Discriminant analysis of principal components and FST analyses based on microsatellites indicated that all five populations formed discrete clusters. Within Europe, Ukrainian populations were most closely associated with populations from the River Danube, suggesting that the Danube is the main source of all Ukrainian pumpkinseed populations. The parasite fauna comprised 15 taxa, most of which (92%) were native to North America (monogenea Onchocleidus similis and O. dispar; myxozoan Myxobolus dechtiari). Parasites acquired in the species' new range occurred accidentally, with only Trichodina ciliates found relatively frequently and the eye flukes Diplostomum pseudospathaceum and Tylodelphys clavata occurring at higher prevalence. Absence of specific monogeneans in pumpkinseed from estuaries (Khadzhibey and Sukhyi Lymans) indicates low tolerance of Onchocleidus species to salinity.

Abstract. The paper considers the ecological variability of the round goby, Neogobius melanostomus (Pall.), in different environments. The dietary spectrum and morphological variability of round goby populations were studied in two water bodies with different environmental conditions. The sizes and body weights of specimens were the largest in Obytichna Bay and the smallest in Kakhovka Reservoir. Differences in the morphological indices of gobies from freshwater and marine bodies of water were determined using discriminant analysis. At the study sites the round goby chiefly fed on benthic organisms that varied in species composition and energy equivalent. A significant portion of the diet comprised bivalves such as Abra ovata, Cerastoderma glaucum, and Parvicardium exiguum, which have the highest energy capacity. The average energy equivalent indices of prey items were higher in Obytichna Bay and the lowest in Kakhovka Reservoir.

Monogenean parasites are often co-introduced with their fish hosts into novel areas. This study confirmed co-introduction of two dactylogyrids, Dactylogyrus squameus Gusev, 1955 and Bivaginogyrus obscurus (Gusev, 1955), and a newly described gyrodactylid species, Gyrodactylus pseudorasborae n. sp. into Europe along with their fish host, the invasive topmouth gudgeon Pseudorasbora parva (Temminck & Schlegel) from East Asia. All three species were observed in the lower Dnieper and middle Danube basin regions and had slightly larger haptoral hard parts than the same parasites in their native range. While dactylogyrids occurred sporadically, we recorded regular infection by G. pseudorasborae n. sp. at relatively high prevalence and abundance. This latter species was observed in both the native and non-native range of topmouth gudgeon, and resembles Gyrodactylus parvae You et al., 2008 recently described from P. parva in China. Both species were distinguished based on genetic analysis of their ITS rDNA sequence (6.6% difference), and morphometric differences in the marginal hooks and male copulatory organ. Phylogenetic analysis of dactylogyrid monogeneans showed that B. obscurus clustered with Dactylogyrus species parasitising Gobionidae and Xenocyprididae, including D. squameus, supporting recent suggestions of a paraphyletic origin of the Dactylogyrus genus. In addition to co-introduced parasites, topmouth gudgeon was infected with a local generalist, G. prostae Ergens, 1964, increasing the number of monogeneans acquired in Europe to three species. Nevertheless, monogenean infections were generally lower in non-native host populations, potentially giving an advantage to invading topmouth gudgeon.

Міжвідомча лабораторія моніторингу екосистем Азовського басейну Інституту морської біології Національної академії наук України та Мелітопольського державного педагогічного університету імені Богдана Хмельницького,

The paper provides information on the structure of sites of the Emerald Network of Ukraine as special areas of conservation, focused at ensuring the protection of natural fauna, flora and habitats. The development of this network was initiated for the implementation of a set of resolutions of the Berne Convention (1979), and principles of its formation are basically similar to Natura 2000. As of 2019, a total of 271 Emerald sites were designated in Ukraine. According to studies, the water bodies of the network are inhabited by 25 fish species. The data were extracted from up-to-date ichthyological publications on the distribution of fish species in Ukrainian water bodies, catalogues of collections of various zoological museums, regional faunal cadastres, and own research. Analysis of the fish species composition in the sites has shown that the most common and found in more than 60% of the sites are Cobitis taenia, Rhodeus sericeus amarus, Misgurnus fossilis. This can be explained by characteristics of their biology and tolerance to environmental conditions. Endemic species are extremely rare in the Emerald sites and narrowly localized in several river basins. In particular, they are Zingel zingel, Umbra krameri, Eudontomyzon danfordi, Hucho hucho, and Leuciscus souffia recorded in 5-6 sites of the network. Further research is required that will be focused at the development of an integral network of Emerald sites in Ukraine. For this purpose, ichthyological reserves of general and local significance may be considered as promising areas. The analysis of the species number and distribution in water bodies of Ukraine is quite relative and requires additional special field studies. In addition, a qualitative assessment of the number of fish species in promising areas requires ichthyological research methods to be unified and an effective monitoring system be introduced.