Effects of pollution on reproductive behaviour of fishes

This review attempts to integrate pollution research with behavioural ecology by focusing on reproductive behaviour of fishes. A search of Aquatic 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 courtship have been investigated using a variety of pollutants (e.g. acidification, herbicide, thermal effluent) in several fish families (e.g. Cichlidae, Poeciliidae, Gasterosteidae, Cyprinidae). Eleven of the 19 studies found a change in behaviour from the norm. Effects on courtship included decreases or increases in frequency of displays, increased courtship duration, or performance of male-like behaviour by masculinized females. Studies of parental care have found decreased nest-building activity, decreased offspring defence, or changes in division of parental care between the sexes. Few studies have measured reproductive success or extrapolated their results to effects on populations. We develop a framework for exploring links between pollution and behavioural ecology which suggests potential impacts on life history trade-offs in 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 behavioural toxicity tests. Choice of such assays would have to compete with the sensitivity and practicality of more traditional methods but may serve as useful complements. There is considerable scope for further research into conservation. A synthesis between behavioural ecology and toxicology should thus provide useful insights for both fields.