其他摘要：Salmonids belong to most important freshwater fishes in terms of commercial and recreational fisheries. In last decades, populations of salmonids have been threatened by many factors including overharvest, water pollution, changes in hydrological regime, predation, hybridisation with non–native fish and many others. In order to prevent decline of salmonid densities reported in last two decades, the evaluation of impact of particular factors on wild populations should be performed. Accurate species identification is a prerequisite for such analyses. However, it is often difficult to unambiguously identify species, especially in cases of early stages and degraded specimens. We aimed at developing a molecular technique for discrimination between the five salmonid species occurring in Slovakia. Three of the species, namely Salmo trutta Linnaeus, 1758, Thymallus thymallus Linnaeus, 1758 and Hucho hucho Linnaeus, 1758, are native in this area. Two North American species, namely Oncorhynchus mykiss Walbaum, 1792 and Salvelinus fontinalis Mitchill, 1814, were introduced in Central Europe at the end of 19th century and widely stocked since that time. The polymerase chain reaction – restriction fragment length polymorphism method was developed for the species identification. A PCR amplified 709 bp segment of mitochodrial gene cytochrom c oxidase subunit 1 was digested with enzymes RsaI and TaqI. The fragments were separated using an agarose gel electrophoresis. The method possessed unique restriction patterns for each species. Analysis of O. mykiss samples generated four fragments, S. fontinalis and T. thymallus three fragments, H. hucho two fragments and S. trutta one fragment. All the patterns were clearly distinguishable from each other. The method proved valuable for the species identification and may be useful for future ecological studies and applied conservation and management purposes.
其他关键词：cytochrome oxidase I; restriction fragment length polymorphism; salmonids; species identification.
