SHORT REVIEW OF SELECTED FISH BIOMARKERS OF XENOBIOTIC EXPOSURE WITH AN EXAMPLE USING FISH HEPATIC MIXED-FUNCTION OXIDASE

One group of biological tools that are useful for monitoring exposure to xenobiotics (and hence water quality) have been collectively referr ed to as biomarkers and are defined in this paper as any biochemical, histological and/or physiological alterations or manifestations of str ess. Biomarkers within an aquatic toxicological context generally repr esent biological responses of individual organisms to xenobiotic expos ure (i.e. responses at the whole organism level of biological organiza tion) These include among others, enzyme alterations, bile metabolites , RNA/DNA ratio, adenylate energy charge, skeletal abnormalities, immu ne dysfunction, behavioural changes and histopathological lesions. Bio markers can act as effective early warning sentinels ro ensure the pro tection of the integrity of whole ecosystems, including freshwater and This paper briefly reviews a selection of fish biomarkers of xenobiot ic chemical exposure and marine ecosystems discusses their respective strengths and limitations for use in biomonitoring. An example of the the application oi fish mixed-function Oxidase (MFO) and cytochrome P- LSO as biomarkers of chemical exposure in Port Phillip Bay is provided it is concluded that judicious application oi biomarkers such as MFO in association with an understanding of the underlying causal mechanis ms of induction and toxicity, will contribute to the successful predic tion of biological effects of xenobiotic exposure on fish population h ealth.