THE COMPARATIVE STUDY OF THE OVERALL EFFECT OF CRUDE OIL ON FISH IN EARLY STAGES OF DEVELOPMENT

The overall toxic impact of crude oil on fish was evaluated in acute and chronic tests by use of rainbow trout (Oncorhynchus mykiss) (embryos, larvae and juveniles). Survival, physiological (heart rate, gill ventilation frequency) and haematological parameters of test objects were studied. Crude oil depending on concentration and exposure duration caused a significant increase in larval mortality, whereas embryos were less and juveniles were least sensitive to the impact of oil. Sublethal crude oil concentrations induced signi- ficant alterations in cardio-respiratory parameters of embryos and larvae, as well as in respiratory and haematological parameters of juvenile fish.