Fish larvae prefer coral over algal water cues: implications of coral reef degradation

Many marine reef fishes have pelagic larval stages that develop in offshore waters. These larvae face the great challenge of relocating to patchily distributed reef environments in a vast oceanic matrix. We explored how chemical cues emitted from coral versus algal reefs attract fish larvae at Rangiroa Atoll (French Polynesia). Experiments with 2-channel choice chambers showed that during the recruitment stage, 7 of the 10 fish species studied preferred water from reefs dominated by coral compared to reefs dominated by algae (e. g. Aulostomus chinensis, Chromis viridis, Ptereleotris microlepis, and Sargocentron spiniferum). Only Zebrasoma veliferum preferred water from reefs dominated by algae. Overall, olfactory cues could play an important role in directing pelagic larval stage fishes to a suitable reef on which they can settle.