| Abstract [eng] |
The dissertation, which was prepared by Tomas Makaras at the Nature Research Centre (2015–2019), addresses the problem of understanding and predicting effects of exposure to sublethal (realistic) environmental concentrations of chemical mixtures (landfill leachate and metal mixture) on various biological endpoints in different fish species. This dissertation has provided new scientific data on acclimation-induced behavioural differences between rheophilic (Oncorhynchus mykiss, Salmo salar) and eurytopic (Perca fluviatilis, Gasterosteus aculeatus) fish species as well as on differences in behavioural response sensitivity and rapidness of the exposed fish species. A new approach to non-invasive glucose measurement procedure for studying short-term stress responses induced by chemical stimuli in fish has been developed and applied. The results obtained show that the time needed for different fish species to acclimate before actual toxicity testing is variable. Fish behavioural and respiratory responses to exposure depend on concentrations of mixtures, exposure duration, and fish age/size. Gill ventilation frequency was found to be the most sensitive and rapid of all the locomotor and respiratory endpoints examined in O. mykiss. This study has revealed that, compared to the model species, P. fluviatilis is behaviourally insensitive to metal mixture exposure. Significant glucose level changes induced by metal mixture exposure were recorded in the holding-water of O. mykiss. |
