“…As the orientation of organisms, image quality, illumination and occluding material increased uncertainty when identifying organisms to the species level, counts of the photographed organisms were divided into the following, clearly identifiable groups: sea urchins (Echinoida and Cidaroida), crabs (Brachyura), hermit crabs (Paguroidea), brittle stars (Ophiuroidea), starfish (Asteroidea), sea cucumbers (Holothuroidea), fish (Osteichthyes), worms (Annelida and Poly chaeta), eels (Muraenidae) and molluscs (Mollusca). These groups were selected based on the ability of the observers to identify organisms in the photographs, frequency of occurrence, and previous work that linked some of these groups to underwater sounds (Moulton 1957, 1960, Cummings et al 1964, Tavolga 1964, Amorim et al 2004, Radford et al 2008, Patek et al 2009, Freeman et al 2014). An example of typical data from a crepuscular period recorded at Kahekili, Maui, is shown in Fig.…”