Abstract
Limited information still exists on the movements of bottlenose dolphins in South Australian coastal waters. There is, however, a need to overcome this paucity of information for an effective development and implementation of conservation and management initiatives in these waters that are increasingly threatened by anthropogenic activities. This study infers potential movements of bottlenose dolphins (Tursiops spp.) between Kangaroo Island that separate and shelter South Australian coastal waters from the Southern Ocean swell, and the South Australian mainland (The Fleurieu Peninsula and The Adelaide Dolphin Sanctuary). Bottlenose dolphins were identified from three separate photo-identification catalogues collated from around the South Australian coastline. Of the 3518, 654 and 181 dolphins sighted in Kangaroo Island, Fleurieu Peninsula and the Adelaide Dolphin Sanctuary, 233, 74 and 40 individuals were recognizable, respectively. Resighting rates were similar in Kangaroo Island (70.4%) and Fleurieu Peninsula (75.7%), but much lower in the Adelaide Dolphin Sanctuary (35%). Ten individuals were resighted between Kangaroo Island and the Fleurieu Peninsula, whilst no matches were made between these two locations and the Adelaide Dolphin Sanctuary catalogue. This suggests a longitudinal connectivity between Kangaroo Island and South Australian mainland waters, but a lack of latitudinal connectivity that may result from the physical stratification processes that separate northern and southern South Australian waters. Our results also demonstrate the highly mobile nature of this species within South Australian waters as well as establish photo-identification as an effective non-invasive tool in which to monitor long-term movement patterns).
Highlights
Bottlenose dolphins (Tursiops spp.) are found globally throughout temperate and tropical seas, and are frequently observed in shallow coastal habitats as well as offshore oceanic waters [1]
Resighting rates were similar in Kangaroo Island (70.4%) and Fleurieu Peninsula (75.7%), but much lower in the Adelaide Dolphin Sanctuary (35%)
Ten individuals were resighted between Kangaroo Island and the Fleurieu Peninsula, whilst no matches were made between these two locations and the Adelaide Dolphin Sanctuary catalogue
Summary
Bottlenose dolphins (Tursiops spp.) are found globally throughout temperate and tropical seas, and are frequently observed in shallow coastal habitats as well as offshore oceanic waters [1]. Providing evidence of such movements and the use of specific locations is the first stage in establishing and implementing effective management strategies [8] This issue is relevant for South Australian waters with the ever increasing range of human impacts in this region, for example, habitat degradation, coastal and industrial development, aquaculture, fisheries, intentional killings and pollution [5] [9]. This is even more of a concern for bottlenose dolphins, which are still relatively unknown in terms of demography, ecology, home range, site fidelity, residency and behavior outside the Port RiverBarker Inlet estuary in particular and in South Australian waters in general. This study documents the first evidence of movements and connectivity of bottlenose dolphins between the South Australian mainland and Kangaroo Island, based upon photo-identification data obtained from 3 separate studies carried out around South Australia
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