Diver ecotourism and disturbance to reef fish spawning aggregations: It is better to be disturbed than to be dead

Dive tourism, with proper diver training, is often suggested as an environmentally benign and economically viable alternative to commercial fishing of coral reef fishes, affording, for example, unique opportunities to see large schools of spawning fish or encounter whale sharks Rhin-codon typus. Yet, the ancillary effects of groups of divers disrupting fish spawning aggregations (FSAs) must be assessed. We examined over 9 h of video footage (extracted from over 100 h of underwater video) filmed at FSA sites in Belize. The footage captured divers interacting with schools of snappers and groupers as they aggregated to spawn, as well as showing the arrival of whale sharks. Diver behaviors included both video recording and flash still photography of fish schools and tagging of whale sharks. We filmed 746 unique diver-school interactions that included total observations of approximately 200 000 snappers, 4700 Nassau groupers Epinephelus striatus and 200 whale sharks. We recorded 180 spawning events, only 105 of which showed divers disturbing aggregating schools, which affected an estimated 2100 snappers and 90 groupers. We conclude that small groups of experienced divers, following a code of responsible diving centered upon the precautionary principle and sensitivity to fish schooling behaviors, do not negatively affect schooling or spawning behaviors. Though further research is needed to assess the effects of boat traffic and larger groups of less experienced divers, dive ecotourism at fish spawning areas represents an economically attractive and less exploitative alternative to commercial fishing.