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Space use by bottlenose dolphins in the Leschenault Estuary and Bunbury waters

Smith, H., Bejder, L., Kobryn, H. and Waples, K. (2013) Space use by bottlenose dolphins in the Leschenault Estuary and Bunbury waters. In: 3rd Biennial South West Marine Conference, 9 May, Bunker Bay, Western Australia.


The space an animal uses and needs for survival is a key concept in wildlife management. Animals within a population do not use their space equally and the size of their home range area and how they use it are important considerations in wildlife management. Home range areas for individual dolphins were estimated using the Kernel Density Estimator and Minimum Convex Polygon methods. Home range size differed between adult male and female dolphins, with males having larger home ranges than females. Females in sheltered inner waters (Leschenault Estuary and Koombana Bay) had smaller home ranges (7.4-24.6km2; N=9) than those females in exposed coastal areas (home ranges: 32.1-125.2km2; N=9). The difference in home range size between adult females was statistically significant (ANOVA: P ≤0.0001). Seasonal differences in ranging patterns showed females had a preference for the lee-side of an artificial groyne adjacent to the Leschenault Estuary cut during the summer and autumn calving season. Habitat use was explored through maximum entropy modelling. Reef habitat had the strongest influence over dolphin presence whilst distance from coast was a weak predictor. Males and some adult females used a larger coastal area. The female dolphins whose small home ranges were exclusively within the inner waters may be at greater risk of threats such as coastal development, vessel strikes, entanglement in fishing gear and compromised water quality. Given these findings, both the coastal and inner water ecosystems are important and management strategies should incorporate both areas to effectively conserve the dolphin population.

Publication Type: Conference Item
Murdoch Affiliation: Centre for Fish and Fisheries Research
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