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Oberlin College

Publication Date

Fall 2007

Program Name

Australia: Natural and Cultural Ecology

Abstract

This study examines ontogenetic shift in habitat and feeding ecology of the black damselfish, Neoglyphidodon melas in three patch reef sites at Lizard Island, Great Barrier Reef. This rarely studied species is unique in its coprophagous relationship with the faeces of the giant clam Tridacna gigas. Distribution and habitat composition between three sites and two reef zones was estimated with 48 Visual Belt and Point Intercept Transects. 80 Focal Animal Studies revealed specific foraging strategies and aggressive behaviours. The timing of this study permitted the inclusion of juvenile recruits resulting in a more complete and comprehensive study across developmental stages. Major results showed marked ontogenetic shifts in both habitat usage and feeding strategies. Recruits fed solely on plankton and were generally found over heads of digitate Acropora. Older juveniles added soft coral to their diet, which was also a major benthic component in high density areas. Only adults consumed clam faeces in addition to soft coral, and larger adults consumed more faeces than smaller adults. Adult distribution was affected by soft coral and rubble, which positively affected clam occupation. Larger fish exhibited greater aggression towards conspecifics and non-conspecifics, but adult fish occupying clams had a lower rate of chasing compared with adults without clams. Protein-rich clam faeces is an important dietary component for large adult fish.

Disciplines

Environmental Sciences | Oceanography

 

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