Thesis
Population Viability Analysis of the Indo-Pacific Bottlenose Dolphin Population in Perth Metropolitan Waters, Western Australia
Masters by Research, Murdoch University
2024
Abstract
Population demographic information plays a crucial role in wildlife management, especially when assessing threats that could endanger the survival of populations. This study presents a detailed assessment of population dynamics for Indo-Pacific bottlenose dolphins (Tursiops aduncus) subpopulations residing in Perth metropolitan waters (Western Australia) using a Vortex Population Viability Analysis (PVA) model approach. Demographic parameters such as age and sex specific mortality and reproductive rates were estimated for the Swan-Canning Estuary (SCE) and Cockburn Sound/Owen Anchorage (CS/OA) subpopulations using boat-based photo-identification data collected from 2011 to 2023. A selection of PVA models were run, with parameters being manipulated to evaluate the impact of current and potential threats on growth rates (r) and survival probabilities of these subpopulations. Given the current demographic rates, both subpopulations are declining (SCE: r = -0.0710, SD= 0.2443; CS/OA: r = -0.0798, SD= 0.2000). Eliminating human-caused deaths, such as fishing line entanglement, increases subpopulation growth rates by 48% and by almost 47% for SCE and CS/OA respectively (SCE: r = -0.0368, SD= 0.2479; CS/OA: r = -0.426, SD= 0.1826). Decreasing calf and adult female mortality rates in the subpopulations yield significant improvement of predicted growth rates by almost 39% in SCE (r = -0.0434, SD= 0.2377), and by 34.5% in CS/OA (r = -0.0523, SD= 0.1845). To enhance the growth rate and reduce the extinction probability of Perth metropolitan dolphins, management efforts should focus on reducing calf and adult female mortality in both subpopulations. The first step toward achieving this goal should be the reduction of human impact related mortality, such as fishing line entanglement, to zero.
Details
- Title
- Population Viability Analysis of the Indo-Pacific Bottlenose Dolphin Population in Perth Metropolitan Waters, Western Australia
- Authors/Creators
- Emma M West
- Contributors
- Professor Jennifer Verduin (Supervisor) - Murdoch University, Centre for Sustainable Aquatic EcosystemsDelphine Chabanne (Supervisor) - Murdoch University, Centre for Sustainable Aquatic Ecosystems
- Awarding Institution
- Murdoch University; Masters by Research
- Identifiers
- 991005674270307891
- Murdoch Affiliation
- School of Environmental and Conservation Sciences
- Resource Type
- Thesis
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