Abstract The recent expansion of the round goby ( Neogobius melanostomus ) in tributaries lower Danube (Bulgaria) prompted assessing potential negative effects on local fish fauna such as competition for food resources. Diet overlap between and native fishes was analyzed using samples macroinvertebrates collected monthly a one-year period. Significant dietary N. Barbus petenyi , Perca fluviatil...

The fishery of bony fishes has an economic important in southern part of Caspian Sea ,but there are few reports about the pathogens of them in this area .Eustrongylides excisus , a parasite (Nematoda: Dioctophymidae) can damage the muscles of bony fishes . So, consumers avoid to buy the infected fish. Hence , the parasite can cause economic loss.In order to determine the occurance and intensity...

Russian ( ), Persian ( ) and Siberian ( Acipenser gueldenstaedtii A. persicus A. ) sturgeons are closely related ‘Ponto-Caspian’ species. Investigation of baerii their population structure is an important problem, the solution of which determines measures for conservation of these species. According to previous studies, ‘baerii-like’ mitochondrial genotypes were found in the Caspian Sea among 3...

Current taxonomy of western Eurasian trout leaves a number of questions open; it is not clear to what extent some species are distinct genetically and morphologically. The purpose of this paper was to explore phylogeography and species boundaries in freshwater and anadromous trout from the drainages of the Black and the Caspian Seas (Ponto-Caspian). We studied morphology and mitochondrial phylo...

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The rapid rise of Caspian Sea water level (about 2.25 meters since 1978) has caused much concern to all five surrounding countries, primarily because flooding has destroyed or damaged buildings and other engineering structures, roads, beaches and farm lands in the coastal zone. Given that climate, and more specifically climate change, is a primary factor influencing oscillations in Caspian Sea ...

Russian ( Acipenser gueldenstaedtii), Persian ( A. persicus) and Siberian ( A. baerii) sturgeons are closely related 'Ponto-Caspian' species. Investigation of their population structure is an important problem, the solution of which determines measures for conservation of these species. According to previous studies, 'baerii-like' mitotypes were found in the Caspian Sea among 35% of Russian stu...