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Occurence of Gobio kesslerii Dybowski, 1862 in the River Morava
Merta, L. ; Lusk, Stanislav
Gobio kesslerii is among the rare species in the ichthyofauna of the Czech Republic. Until recently, this species has been only know to occur in the River Bečvy (a tributary to the Morava River). In the autumn of 2003, numerous G. kesslerii were ascertained in the River Morava between the mouth of the r. Bečva (r.km 210.7) up to the weir at Bolelouc (r.km 221.04).
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Some biological characteristics of the invasion species Perccottus glenii
Halačka, Karel ; Vetešník, Lukáš ; Koščo, J.
The occurrence of this exotic species was first observed in the Latorica River, E Slovakia, in 1998. Perccottus glenii occupied the rivers Latorica, Bodrog and Tisza together with the aquatic habitats in their floodplains. We carried out analysis of growth, haematology, fecundity, morphology of skin and gonad of individuals Amur sleeper in the locality at Svata Maria (the Bodrog River drainage area). In the locality under study the invasion of Perccottus glenii resulted in an almost total destruction of numerous populations of the native species Umbra krameri, Carassius carassius, and Leucaspius delineatus. In the past, these species were among the most numerous in that locality. Perccottus glenii has appeared to be a typical 'invasive' species that is a serious threat for native fish species showing identical habitat requirements.
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