TROPICAL REEF FISH SPAWNING AGGREGATIONS - DEFINED AND REVIEWED

The formation of spawning aggregations at specific locations and times is a common mode of reproduction for species in some tropical reef fi sh families. A spawning aggregation was broadly defined as a gathering of conspecific fish, for the purposes of spawning, that consisted of fish densities significantly higher than are found during the non-repr oductive period, or for fishes that normally occur in dense schools, m ust occur in significantly greater number and take up significantly mo re space. Two spawning aggregation types, resident and transient, were defined and applied to examples in the literature. These aggregation types were defined based on differences in 1) the frequency with which the spawning aggregation occurs, 2) the length of time the aggregatio n persists, 3) the site specificity of the aggregation, and 4) the dis tance individual fish travel to the aggregation site. As a result of t he above criteria an individual's relative contribution towards its to tal annual reproductive output, made at a single spawning aggregation, is vastly different between the two aggregation types. Review of the literature resulted in tramples of serranid, lutjanid and siganid spaw ning aggregations being classified as transient spawning aggregations, while scarid, labrid and acanthurid spawning aggregations were deemed to be resident spawning aggregations. Examples of spawning aggregatio ns from other families, which lack sufficient data to he classified, a re also reviewed.