by gynogenesis may facilitate the expansion activities of gibel carp
when introduced into the breeding ponds of common carp. As a result,
gibel carp may represent a threat to common carp production due to
competition for food and space (Vetešník, pers. com.). On the basis of
morphology and molecular diagnostics, the occurrence of common
carp x gibel carp hybrids following the invasion of gibel carp into breeding ponds for common carp has recently been reported (Šimková et al.,
2012).
The aim of this study was to analyze how hybridization affects
selected biochemical blood, physiological and immune parameters. Because fish physiology and immunity are strongly influenced by seasonal
changes through the effect of water temperature, we included samples
from two different sampling periods, i.e. spring (when fish physiology is
activated following seasonal changes linked with an increase in water
temperature) and autumn (the so-called post-spawning period) in
order to test the effect of sampling period on the selected measures of
fish physiology and immunity.