Population dynamics and habitat use of bottlenose dolphins (Tursiops aduncus), Bunbury, Western Australia

摘要: Coastal dolphins are increasingly exposed to a variety of human activities through the proliferation coastal development. Threats in near-shore environments include loss suitable habitat, increasing vessel traffic and tourism, entanglement fishing gear or other marine debris, noise pollution, environmental contaminants disease. Baseline data long-term monitoring needed inform effective management initiatives conserve dolphin populations. This study focused on bottlenose (Tursiops aduncus) population that inhabits waters around rapidly developing city Bunbury, Western Australia. investigated spatial temporal variability abundance, social dynamics, calving seasonality, home range size habitat use Bunbury over three-year period. From 2007-2010, year-round boat-based, photo-identification surveys followed pre-determined transect lines within 120 km2 area (212 total; N=578 group encounters) achieve intensive consistent sampling effort. Abundance demographic parameters were estimated using capture-recapture Robust Design model. The model with Markovian temporary emigration was favoured varying (survival, capture probability time). estimates varied from 65 individuals (± SE 8.53; 95% CI: 54- 90) winter 2007 139 (±SE 3.41; 134-148) autumn 2009. apparent adult survival estimate 0.985 0.006; 0.964- 0.994). Calving peaked late February early March. Associations between females showed an annual seasonal cyclic pattern during breeding season. Home important identifying critical areas. areas for individual Minimum Convex Polygon method occupied statistically different sized (ANOVA: P ≤0.0001). Females sheltered inner (Leschenault Estuary Koombana Bay) had smaller ranges (7.4-24.6km2; N=9) than those (home ranges: 32.1-125.2km2; N=9). Seasonal differences ranging patterns analysed kernel density hotspot method. During summer season, there lee-side artificial groyne, adjacent Bay. Habitat explored further maximum entropy modelling. Reef strongest influence presence whilst distance coast weak predictor. Managers can now focus protecting this habitat. project has demonstrated benefits multi-year research by detecting behaviour – information managing impacts species. Future should combine our understanding conduct risk assessment rank threats these dolphins.