Osoblaha river; ichthyofauna; species diversity; abundance; biomass;flood; fishery management

Byl proveden ichtyologicky vyzkum povodi ricky Osoblahy na uzemi Ceske republiky. V prubehu ichtyologickeho pruzkumu v letech 1997 a 1998 byl na 9 lokalitach v povodi Osoblahy zjisten vyskytjednoho druhu mihulovcu (mihule potocni) a 17 druhu ryb. Horní úsek toku má charakterpstruhové vody. V dolni casti ma rybi osidleni prechodny raz k parmovemu typu. Byl zjisten vyrazny vliv rybniku na druhovou skladbu rybiho osidleni. V useku Bohusov (r. km 7,9 Osoblahy) byl vyhodnocen vliv povodne v cervenci 1997 na rybi osidleni. Povodnovy prutok tam 8. cervence 1997 dosahl 137,9 % tzv. stolete vody (Q-100 = 103 m 3.s-1 ). Puvodni rybi osidleni se v prubehu povodne zasadne nezmenilo. Hodnoty indexu diverzity ve zkoumanych usecich toku v povodi Osoblahy byly pomerne vyrovnane (1,570-1,844). Intenzita rybářského obhospodařování povodí Osoblahy je poměrně nízká vyjma menších přítoků, které jsou obhospodařovány jako úseky pro odchov násad pstruha obecného.

Ichthyological investigations of the fish communities inhabiting the river network of the Osoblaha river in the territory of the Czech Republic have revealed the occurrence of one lamprey species (Lampetra planeri) and 17 species of fishes. The upper reaches of the Osoblaha and its tributaries are populated by a community of the trout type. In the lower part of the stream occur species of the barbel community. The species composition beyond the headwater region is significantly influenced by the presence of minor reservoirs and fishponds in the drainage area of the Osoblaha. The species diversity index H' varied in the range 1.570-1.844. In the section in r. km 7.9 of the rivulet Osoblaha, the status of its fish community was assessed shortly before and after the July 1997 flood. After the flood discharges no marked changes were ascertained in the fish community of the section under study. The fishery management intensity is low.