Brown Trout, Siberian Bullhead, interaction, streams of orders I and II

V našem příspěvku jsme na základě našich dlouhodobých výzkumných aktivit v oblasti Beskyd a Jeseníků vyhodnotili data, která dokumentují stav populací vranky pruhoploutvé v kontextu s výskytem pstruha obecného v potocích, které jsou využívány pro odchov jeho násad.

Results obtained from long-term investigations in brooks inhabited by dominant and sympatric populations of Siberian Bullhead, Cottus poecilopus, and Brown Trout, Salmo trutta m. fario, served to estimate the possible mutual influence of the status of the two populations mentioned. The Siberian Bullhead, a species protected by law in the Czech Republic, occurs predominantly in mountain and submontane brooks in the drainage areas of the Odra and Morava rivers. The population status of Siberian Bullhead was assessed in several tens of localities in the Beskydy Mts. region. The brooks under study are used to rear Brown Trout stocks 1 - 2 years old. The brooks are populated by the populations of the above two species only. The numbers of yearling Siberian Bullhead averaged 2218 exx.ha-1 and 1120 exx.km-1 of the stream (i.e. 47.2 % of the overall abundance), and their biomass 15 kg.ha-1 and 7.6 kg.km-1 (i.e. 14.9 % of total biomass).