The ecology of the bar bellied sea snake (hydrophis elegans) in Shark Bay, Western Australia

This thesis examines factors underlying habitat use of the sea snake Hydrophis elegans and nearshore fish in Shark Bay, Western Australia. Differences in morphology, life history and diet between H. elegans and a syrnpatric sea snake, Disteria major, may facilitate co-existence by reducing competition through inter-specific resource partitioning. Morphological differences between sexes of H. elegans may reduce intraspecific competition. Tidal state may cause changes in predation risk and prey availability. Field observations showed that at low tide H. elegans foraged over shallow sand flats, which are inaccessible to the predatory tiger shark (Galeocerdo cuvier). At high tide, snakes and their potential prey (small fish) moved to deeper seagrass habitats, suggesting that these habitats grant snakes increased safety from predation, as well as access to potential prey. This is more likely true for D. major, because H. elegans appears to specialize on snake-eels (Family Ophichthidae), which occur mainly in sand habitats.