Field and experimental studies of hybridization between coral trouts, Plectropomus leopardus and Plectropomus maculatus(Serranidae), on the Great Barrier Reef, Australia

Abstract

Spawning aggregations of closely‐related coral trouts, Plectropomus leopardus and Plectropomus maculatus, were found to overlap in time and space on the Great Barrier Reef, thus providing opportunities for accidental hybridization by juxtaposition of heterospecific gametes. The relative abundance and mating strategy of coral trouts also favoured hybridization, since mates could be either rare in some habitats or monopolized by dominant fishes. In the latter case, sneak spawning may have occurred, even when behavioural barriers to reproduction (e.g. assortative mating) were operational. When heterospecific gametes were experimentally mixed, fertilization occurred and hybrid larvae developed. It was concluded that there was considerable opportunity for natural hybridization between coral trouts of the genus Plectropomus.