We identify dolphins by the unique nicks and notches on the trailing edge of their dorsal fin.
Before we deem a dolphin as a newly observed individual and give it a name, we compare its dorsal fin to photographs of all others we have on record from our study area in Mandurah, as well as the catalogues we’ve made through long term studies off Perth and Bunbury.
To date we have matched eleven dolphins sighted in Mandurah to dolphins in the Perth catalogue and four to the Bunbury catalogue.
This information is very valuable to us to better understand the movement and ranging patterns of the dolphins that occupy waters off Mandurah.
In Bunbury male dolphins have been found to have larger home range areas than females.
We’ve also found that animals that use mainly coastal waters have larger home range areas than those that mainly use the inland or inshore waters.
These home range areas can vary from about 20 square kilometres to about 200 square kilometres.
Since we started our research in January, the furthest distance we know Mandurah individuals have moved is about 60 km along the coast.
These two animals, Beaker and Bunsen, are thought to be male dolphins.
We saw them at the southern end of our study area this year, and they have been seen in waters off Bunbury five times since 2009.
We have also observed an individual dolphin, Yorkie, travelling from the northern end of Comet Bay to visit the Peel Inlet.
As our research continues we will hopefully better understand the complicated and individually varying movement patterns of the Mandurah dolphins.
The Mandurah Dolphin Research Project is a partnership between Murdoch University, City of Mandurah and Mandurah Cruises that commenced in January 2016.
They are measuring how many dolphins use the Peel-Harvey waterways and how they are connected to dolphins in nearby coastal waters.
You can follow the project on Facebook or through this fortnightly column.