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Community ecology of parasites of chub fry (Leuciscus cephalus L.)
Dávidová, M. ; Jurajda, Pavel ; Gelnar, M.
The formation and development of metazoan parasite community of chub fry (Leuciscus cephalus L.) was followed in the period from July 2000 to May 2001. Chub fry (N=190) were sampled monthly from the River Morava. Altogether 27 parasite species have been recorded. The most common parasites in the investigated locality were representatives of the class Monogenea, especially viviparous gyrodactylids. First, juvenile fish 29 mm in size were found to be infected with ectoparasites and metacercariae. On the opposite, host fish larger then 50 mm were colonised with intestinal parasites.
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The effect of posthodiplostomosis on the cyprinid fish fry
Ondračková, Markéta ; Dyková, Iva ; Gelnar, M. ; Jurajda, Pavel
Posthodiplostomosis, called also black-spot disease, is caused by metacercariae of Posthodiplostomum cuticola (Trematoda, Diplostomatidae). These parasites were studied on the cyprinid fish in floodplain area of the River Dyje in South Moravia. Twelve species from 16 totally explored Cyprinids were infected by metacercariae of P. cuticola during 1998, 1999 and 2001. Roach (Rutilus rutilus), rudd (S. erythrophthalmus), silver bream (B. bjoerkna), common bream (A. brama), bitterling (R. sericeus) and Prussian carp (C. auratus gibelio) were infected in all followed seasons. These species were histologicaly examined. During the cyst development the progressive maturation of connective tissue in outer layer of the cyst and infiltration of pigment cells were observed. Production of black pigment around the parasite cyst was chacteristic host reaction. Mainly melanocytes and in a small measure iridocytes took part in the pigmentation. The metacercariae of P. cuticola caused in the juvenile fish spine and body deformation. By high invasion the tissue dystrophy was observed.
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Impact of water quality and physical habitat degradation upon fish biodiversity in small streams of the Czech Republic
Adámek, Z. ; Jurajda, Pavel
The data obtained during the surveys of fish assemblages in Czech streams of the Danube and Elbe river basins were evaluated with respect to the relation between fish biodiversity and level of water (organic pollution) and/or physical habitat quality (longitudinal heterogeneity, substrate, riparian vegetation, canalisation). Fish asseblages showed the highest biodiversity in betamezosaprobity in both lowland and highland streams. Their response were more pronounced regarding water quality rather than physical habitat deterioration, i.e. fish biodiversity declined with decreasing water quality more considerably than with physical habitat degradation.
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Methodical notes to morphometric studies in ichthyology
Mazurová, E. ; Zukal, Jan ; Jurajda, Pavel
Comparison of 30 morphometric characters is made between measurements made by two persons and between re-measurements made by one person. There are considered statistically significant differences in both measurements, e.g. in characters on head (eye diameter) and on tail (tail height, minimum body height). Also the effect of increase of different characters amount is considered. That is induced by index expression of characters (in % of body length, head length, total body length).
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Comparison of point abundance and sampling methods for 0+ fish
Janáč, M. ; Jurajda, Pavel
We compared structure of 0+fish assemblages estimates given by two different sample strategies: point abundance sampling (PAS) and continual sample method (CS). No statistital significant difference was found betweem both strategies in number of species, dominance and indices of diversity. CS is more time consuming sampling strategy.
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