EFFECTS OF POLLUTION ON REPRODUCTIVE-BEHAVIOR OF FISHES

This review attempts to integrate pollution research with behavioural ecology by focusing on reproductive behaviour of fishes. A search of A quatic Sciences and Fisheries Abstracts and other sources showed that only 0.1% of 19,199 studies of aquatic pollution and fishes during the past 20 years have made this link. Effects on parental care and court ship have been investigated using a variety of pollutants (e.g. acidif ication, herbicide, thermal effluent) in several fish families (e.g. C ichlidae, Poeciliidae, Gasterosteidae, Cyprinidae). Eleven of the 19 s tudies found a change in behaviour from the norm. Effects on courtship included decreases or increases in frequency of displays, increased c ourtship duration, or performance of male-like behaviour by masculiniz ed females. Studies of parental care have found decreased nest-buildin g activity, decreased offspring defence, or changes in division of par ental care between the sexes. Few studies have measured reproductive s uccess or extrapolated their results to effects on populations. We dev elop a framework for exploring links between pollution and behavioural ecology which suggests potential impacts on life history trade-offs i n reproduction, genetic changes in populations, and population sizes. Many reproductive behaviours of fish species are readily quantifiable and behaviours such as courtship by male guppies and other members of the Poeciliidae show some promise for pollution monitoring and behavio ural toxicity tests. Choice of such assays would have to compete with the sensitivity and practicality of more traditional methods but may s erve as useful complements. There is considerable scope for further re search into conservation. A synthesis between behavioural ecology and toxicology should thus provide useful insights for both fields.