The Port Phillip Common Dolphin Project is a long-term research initiative led by the Dolphin Research Institute, dedicated to understanding and protecting the unique community of common dolphins (Delphinus delphis) that call Port Phillip home.
This unique community of dolphins is remarkable because everywhere else in the world, common dolphins live in the open ocean. Port Phillip is the only known place where this typically oceanic species resides in a shallow embayment. They share Port Phillip with approximately 120 bottlenose dolphins and five million people.
The community was first observed in 2005, when researchers spotted just five individuals, including one named ‘V-Nick’, who became the first entry in our Port Phillip Common Dolphin Catalogue.
20 years later, we continue to monitor these dolphins through regular scientific surveys. Our catalogue now includes over 160 individually identified dolphins who have used or continue to use Port Phillip.
Common dolphins can be individually identified by the unique features of their dorsal fins. This includes the fin’s shape, colouration, and any distinctive nicks or notches they accumulate over time. This ability to track individual dolphins has allowed us to monitor the population across decades.
From this, we’ve confirmed the birth of at least 10 third-generation calves since they first entered the Bay. We’ve also documented movements of dolphins from near Mornington in Port Phillip to the Bass Strait waters near Wonthaggi, showing that this study extends beyond the bay
The following figure shows the growth in the number of identified individuals over time. To reduce variability due to survey effort or method changes, we’ve averaged sightings across five-year blocks. The most recent estimate is an average of 59 individuals for 2020 – 2023.
