There'll be lots of people flocking to the beaches and headlands this weekend -- not for a swim but hoping to spot a passing whale or dolphin.
The "cetacean census", as the Canadian-inspired event is known, uses the overall count to help measure the collective health of local whale and dolphin populations.
It also means lots of beautiful sea shots on the event's Facebook page, which has 15,000 followers.
Organiser Christine Rose spoke to Corin Dann.
