Informace o publikaci

The impact of environmental stress on chub (Leuciscus cephalus) and their parasites



Rok publikování 2007
Druh Další prezentace na konferencích
Fakulta / Pracoviště MU

Přírodovědecká fakulta

Popis he main aim of this study was to monitor effects of aquatic pollution on parasites and their hosts and to find reliable indicators of environmental stress. As a model host was chosen freshwater fish chub (Leuciscus cephalus (L.)), collected at two model sites with different level of pollution in Vlára and Bílina Rivers (Czech Republic). Polycyclic aromatic hydrocarbons (PAH) appeared to be predominant organic pollutants at both sites, and their levels were elevated particularly in Bilina River. By contrast, the concentrations of polychlorinated biphenyls (PCB) were very low at both sites. Concentrations of PAH metabolite 1-hydroxynapthol (1-OH-Nap) in fish bile, PCB congeners and heavy metals in fish muscle were measured. EROD activity was used as a specific biomarker of dioxin like compounds (PAH, PCB, dioxins). The induction of EROD activity was significantly elevated at the Bílina River and a positive correlation between EROD activity and concentration of 1-OH-Nap in fish bile was found at both sites. Developmental instability measured as fluctuating asymmetry (FA - define as a deviation from perfect bilateral symmetry) was assessed for both chub and their parasite Dactylogyrus folkmanovae. There were no significant differences in FA among fish collected from different sites. A higher level of FA (the index of hook basis traits) was found for D. folkmanovae from the locality Bilina, however, this effect could be caused by variation in measurement error. There were no correlations between FA in the parasites and their hosts or other data on chemical contamination. The parasite communities were fractionated according to host specificity into generalists and specialists, and analyzed in relation to levels of pollutants and chemical stress biomarkers. There was no relationship between the presence of either specialist or generalist parasites and the exposure to dioxin like compound (measured as EROD activity) at either one of the sites. We confirmed the resistance of representative of family Diplozoidae (Paradiplozoon megan) and a higher sensitivity of the genus Dactylogyrus to pollution. From all the measured variables, EROD activity is a quality parameter for estimating the contamination of environment by PAH pollutants. Other variables, such as FA or the presence of either specialist or generalist parasites seem to be insignificant for assessing environmental stress.
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