Dive into the fascinating world of Perth's dolphins, where seasonal feasts, close-knit communities, and remarkable resilience define their lives! These intelligent creatures, inhabiting the waters of Western Australia, offer a captivating glimpse into marine life.
For over a decade, Dr. Delphine Chabanne, a dedicated researcher from Murdoch University's Harry Butler Institute, has been studying these amazing animals. Her passion stems from a lifelong fascination, as her name itself, derived from the Latin word for 'dolphin' (Delphinus), suggests. Dr. Chabanne's work often involves citizen scientist volunteers, highlighting the community's involvement in understanding and protecting these marine mammals.
Dr. Chabanne presented her findings to students in late 2025 as part of the Western Australian Marine Science Institution's (WAMSI) 'Thinking Blue' education program. This program connects students with leading researchers through online talks.
"There are three species of coastal dolphins in Western Australia, but here in Perth, we find the Indo-Pacific bottlenose dolphins," Dr. Chabanne explained.
Approximately 120 dolphins primarily reside in Cockburn Sound and Owen Anchorage, while about 25 inhabit the Swan-Canning estuary.
"Sometimes, dolphins from the Swan Canning estuary are seen with those in Cockburn Sound, potentially mating," Dr. Chabanne noted. "While rare, movement between communities has also been observed. For example, 'Hugs' was born in Owen Anchorage but has spent most of her time in the Swan Canning estuary since having her first calf in 2021."
So, how do scientists study these elusive creatures?
Dr. Chabanne describes dolphin surveys involving boat travel along parallel or zig-zag lines to locate dolphin groups. When spotted, researchers photograph the dolphins, record group composition, and observe their behavior. Environmental conditions, such as water temperature and depth, are also documented whenever possible.
"We photograph the dorsal fins because each one is distinctive," she explains. "Dolphins are born with smooth fins, but over time, they develop unique nicks, scars, and notches that allow us to track them."
Since 2011, a 'Finbook' on the River Guardians website has helped identify local dolphins in the Swan-Canning estuary.
Dolphins often face significant injuries, including shark bites. But here's where it gets controversial: Dolphins are generally resilient to these bites, except when the injury occurs on their softer bellies, where vital organs are located.
What's on the menu for these Perth dolphins?
Perth's dolphins are opportunistic eaters, adapting their diets with the seasons. In summer, they tend to feast on benthic detritivore fish, like mullet. During winter, they prefer cuttlefish and octopus. Interestingly, despite having teeth, dolphins often toss octopus into the air to break it into smaller pieces before swallowing.
What are the biggest threats to these amazing creatures?
"One of the biggest dangers is fishing lines and nets in the water that can tangle dolphins," Dr. Chabanne stated. "Removing the gear can be very difficult, and because of their size, thinner blubber, and their limited awareness of their environment, dolphin calves are particularly vulnerable to fishing gear entanglement."
Boat strikes are another threat, and underwater noise pollution can disrupt their behavior, as dolphins rely on sound for navigation and hunting.
Keeping waterways clean and free of pollution is also crucial for their health. The Cetacean Morbillivirus, which weakens their immune systems, has caused dolphin deaths around Perth. Tragically, some of the six dolphins found dead in 2009 and another five in 2019 were infected with the virus.
Let's dive into some fascinating dolphin facts!
- Females can live for around 40 years, while males live about 35 years.
- They use clicking sounds and echolocation to understand their surroundings and find food.
- Dolphin pregnancies last 12 months, with calves staying with their mothers for 3 to 5 years to learn essential skills.
- Dolphins rest one half of their brain at a time, allowing them to remain alert for predators or danger while surfacing for air.
How can we help protect these incredible creatures?
- Keep oceans, estuaries, and coastlines clean and tidy.
- Participate in beach cleanups to prevent rubbish from entering the water.
- Dispose of fishing lines and gear responsibly.
- Reduce boat speeds in areas where dolphins are present.
- Avoid feeding dolphins.
- Join a citizen science program.
Are you as fascinated by these dolphins as we are? What do you think is the most significant threat to their survival? Share your thoughts in the comments below!
For more information, you can explore the Harry Butler Institute's Centre for Sustainable Aquatic Ecosystems at Murdoch University.
This article was authored by WAMSI and is reproduced with permission. Photo courtesy of WAMSI.
