Westport has partnered with the Western Australian Marine Science Institution (WAMSI) to deliver the $13.5 million WAMSI-Westport Marine Science Program. This 3-year program is developing the latest data, information and modelling on the complex environmental systems and community values associated with Cockburn Sound.
Project 8.3c: Fine-scale understanding of Indo-Pacific bottlenose dolphin use of the Kwinana Shelf within Cockburn Sound and identification of key areas within the Shelf
Research theme: Apex Predators and Iconic Species
Researchers: D. Chabanne
Publication Date: October 2024
The Indo-Pacific dolphins are well known to frequent the shallow embayment of Cockburn Sound and the Kwinana Shelf.
To better understand their distribution patterns, including preferred habitats and locations, seasonal changes, foraging and travel habits, this study undertook detailed surveys in Cockburn Sound over nearly 2 years to observe the patterns of dolphin behaviour.
Just over 30 boat-based surveys were undertaken to study dolphin numbers and groupings. The study also took into account other variables including surface water temperature and visibility, salinity and oxygen saturation, the location of fishing activities and seasonal variation in environmental conditions.
Ensemble modelling was then used to develop distribution models for the dolphins.
Environmental variables such as sea surface temperature, salinity and oxygen saturation, along with anthropogenic variables such as fishing activities were found to influence dolphin distribution.
What the report found
- Dolphins are present year-round on the Kwinana Shelf, with around 150 dolphins including juveniles using the area, some on a long-term basis.
- Mother and calf pairs were prevalent (in 70% of the groups), highlighting the importance of the Kwinana Shelf for nursing activities.
- Environmental variables such as sea surface temperature, salinity and oxygen saturation, along with anthropogenic variables such as fishing activities were found to influence dolphin distribution.
How Westport will use the report
The study provides valuable insights into the distribution of dolphins in Owen Anchorage and Cockburn Sound and adds context to the historical baseline knowledge of these species within the Kwinana Shelf area. The report will be used to inform Westport environmental management activities, with a view to supporting the long-term health of Cockburn Sound.
Read the full report here.
