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The natural fish reproduction of lowland stretches of Morava and Dyje rivers
Valová, Z. ; Jurajda, Pavel
Lowland rivers decreased their habitat diversity and get an uniform character due to their regulation and channelisation. This modifications affected the natural fish reproduction. The efficiency of natural fish reproduction was studied using Point Abundance Sampling strategy by electrofishing in three differently modified stretches of two adjacent lowland rivers in the late summer of 1999-2003.
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Comparison of efficiency of different electrofishing techniques for juvenile fish estimates on river beach
Janáč, Michal ; Jurajda, Pavel
The efficiency of three PAS electrofishing techniques (direct electrofishing, throwing of anode and remote electrofishing) for 0+ juvenile fish estimates was tested on gravel beaches of the Morava River. All three techniques yielded significantly different assemblage structure (in terms of relative abundances of most abundant species). Both direct electrofishing and throwing of anode disturbed fish what lowered their efficiency on these shallow habitats (30% efficiency in comparison with remote electrofishing). Remote electrofishing was the most effective technique; moreover it yielded significantly more species per locality than other two techniques. Higher time consumption, caused by higher number of fish caught, may be its only constrain in common monitoring, however it is negligible in comparison with its benefits.
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