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The occurrence of brook lamprey [Lampetra planeri (BLOCH, 1784)] in Novohradské Mountains (South Bohemia, Czech Republic)
Matěnová, V. ; Matěna, Josef
The occurrence of brook lamprey was studied in Novohradské Mountains during 1999-2003. Altogether 83 profiles on 22 second to fourth order brooks and streams were fished by means of electroshockers. The area investigated can be divided into three basins. Significant differences were found between basins with respect to frequency of occurrence and density of lamprey populations. The highest frequency of occurrence was in the Stropnice River basin (6 streams of 8 investigated, average abundance 2598 inds ha-1), followed by the Malše River (4 streams of 8 investigated, average abundance 844 inds ha-1). In the Černá Rivulet basin only in 1 of 6 streams investigated the brook lamprey was found at very low densities - 28 inds ha-1 on average. The lamprey contributed substantially to the whole forming more than 50
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The genus .i.Chironomus./i. MEIGEN (Diptera, Chironomidae) in the Novohradské Mountains (South Bohemia)
Matěna, Josef ; Matěnová, V.
The occurrence of Chironomus species was investigated in Novohradské Mountains during 1999-2001. Fishponds, running waters and small standing waters of both permanent and astatic characters were included. Larvae were identified cytotaxonomically according to polytene chromosomes of salivary glands. Ch. annularius occurred more regularly in fishponds without fishery management, further species were found only in some of these habitats - Ch. balatonicus, bernensis, obtusidens, parathummi, plumosus, sp. - near muratensis and Ch. (C.) tentans. Organically polluted stretches of running waters were characterized by mass occurrence of Ch. riparius. Ch. luridus and Ch. melanotus were the dominant species of small permanent water bodies, further species found in these habitats were Ch. aberratus, commutatus, dorsalis, holomelas, piger and pseudothummi. Astatic habitats - rainpools were inhabited almost exclusively by Ch. dorsalis.
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Chironomid communities of the Upper Stropnice River (Novohradské Mountains, South Bohemia)
Chalupová, Š. ; Matěna, Josef
The communities of chironomid larvae of the Upper Stropnice River were studied semiquantitatively between the river kilometres 40-55 during 2000 and 2001. Altogether 29 taxa were observed. Dominant forms were .i.Apsectrotanypus trifascipennis./i., .i.Macropelopia nebulosa./i. and .i.Prodiamesa olivacea./i.. The water quality calculated according to the chironomid communities corresponds to beta-mesosaprobity, only in the area of Upper Stropnice village it deteriorates to alfa-mesosaprobity. This fact gives evidence to presence of point sources of organic pollution. Further downstreams the values of saprobity return to the state above the source of organic pollution. In the anthropically influenced area of the stream the decrease in the diversity of chironomid communities occured. It is necessary to consider the results as preliminary, because the only family Chironomidae was analysed in detail, for exact results the analysis of the whole macrobenthic community is necessary.
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The diet of larval and juvenile pikeperch (.i.Stizostedion lucioperca./i.)(L.)), comparative study of fishponds and a reservoir
Peterka, Jiří ; Matěna, Josef ; Lipka, J.
Diet of larval and juvenile pikeperch (.i.S. lucioperca./i.) reared in ponds was investigated and compared with the diet of pikeperch from a reservoir. Numbers of rotifers were found low in the diet of pikeperch larvae in fishponds and they were soonreplaced by nauplii of cyclopoid copepods. .i.Daphnia./i. spp. were consumed from the onset of exogenous feeding. Another smaller cladoceran .i.Bosmina./i. longirostris did not contribute to the diet significantly. In the reservoir, rotifers were not found in the diet of pikeperch larvae. Dominant food items were nauplii and 1st copepodite instar of .i.Eudiaptomus gracilis./i. and .i.Cyclops./i. spp. .i.Daphnia galeata./i. and to a lesser extent .i.Diaphanosoma brachyurum./i. appeared in the pikeperch diet at a length of about 10 mm. A shift towards larger prey, especially .i.Leptodora kindtii./i., could be recognised in pikeperch at a length of 20 mm. Growth of pikeperch was found faster in nursing ponds than in the reservoir.
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Diel fluctuation of fish catches taken by pelagic gillnets in the Římov Reservoir
Vašek, M. ; Čech, M. ; Draštík, V. ; Dušek, D. ; Hladík, M. ; Kubečka, Jan ; Matěna, Josef ; Peterka, J. ; Pokorný, P. ; Prchalová, M. ; Štafa, P.
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