Ichthyologic monitoring the flow of Popelka in Nová Ves nad Popelkou

The aim of this work is to evaluate ichtyofauna in the stream Popelka, to determine the species composition of fish stoce and to determine the dominant fish species, their abundance and size variability. Throughout the length of the flow, twelve catching sites were identified there, the length of each site was about 50 m, the catch in these sites was from the bottom of the upstream towards the end. The catch of the flow was by wade manner with use of an electric aggregate. All caught fish species were subsequently determined. Also the body lenght so-called ?standart lenght? was measured. After measuring all fish that were caught were gently given back to the place of the catch. In terms of abundance the most numerous species in Popelka was brown trout represented by 477 subjects followed by stone loach with 391 subjects. These species clearly dominated in Popelka. Another occurring species were rainbow trout with 49 subjects, brook charr with two subjects and hybrid of brown trout and brook charr with one subject. With regard to the regional constance the brown trout was a species almost always present, with presence in 11 out of the 12 sites. Stone loach with incidence in 8 locations was mainly occurring species. With the appearance in 5 localities the rainbow trout was frequently occurring species. Among the species that are rare in Popelka, there were brook charr occurring in two locations and hybrid of brown trout and brook charr with the appearance in one location. Index of species diversity by Shannon and Wiener for the flow of Popelka is 0.88 and evenness is 0.55. Size variability across the flow in body length of brown trout was ranging from 46 to 308 mm, in diameter 126.4 mm, the stone loach from 41 to 130 mm, in diameter 80.1 mm, the rainbow trout from 65 to 250 mm, in diameter 88.7 mm and brook charr from 290 to 313 mm with an average of 301.5 mm. In the Popelka stream with a total length of 12 km there are four species of fish in these fish communities. Species diversity is distinctly poorer in comparison with the other streams. It would be appropriate to repeat the catch in the future to determine the stability of fish population in Popelka stream