An optimised passive acoustic sampling scheme to discriminate among coral reefs’ ecological states

•Five acoustic indices consistently discriminate among coral reefs’ ecological states.•The acoustic sampling scheme performs well in the Indian and Pacific oceans.•Indices for frequencies >2 kHz need very short recording times (≤20 min) at night.•Indices for frequencies <1 kHz need longer recording times (≥200 min) at night.•We propose guidelines for acoustic sampling of coral reefs or other marine habitats.