Humpback whale identi-kit more than a fluke
Just as humans can be identified by their facial features, humpback whales have identifying features on their tails or ‘flukes’.
Captured on film, these features can be used by biologists to estimate the abundance of whales and to monitor individuals in a population year after year. Tens of thousands of photos of the flukes of Southern Hemisphere humpback whales have been taken over the years, providing an incredible database of information. But as the number of photos increases, so does the difficulty of manually comparing images to find a match.
Through the Australian Centre for Applied Marine Mammal Science, Dr Eric Kniest, of the University of Newcastle, and Professor Peter Harrison and Mr Daniel Burns, of the Southern Cross University Whale Research Centre, will complete development of the first computerised fluke matching system for humpback whales in Australia and the South Pacific region.
The system will standardise each fluke image for computer matching – scaling and rotating images onto a common reference system. This means that photos taken from different angles, at different distances, or with water obscuring parts of the fluke, will all fit a standard template. The database will also record visual and measurable elements of each fluke, such as the pattern of black and white patches, the distance between the fluke tips, and the shape of the fluke tips. When a new photo needs to be matched against those in the database, researchers will simply need to enter information on some of these common visual or measurable points.
‘There will also be scope to include additional features in the database, such as scratches, to improve the matching process,’ Dr Kniest says.
In a database of 1000 flukes, the photo-identification matching system will take only a few minutes, compared to up to an hour for an experienced operator comparing photos manually.
A working version of the system has already been developed through a previous pilot study in 2004, but will now be refined for more efficient searching of larger fluke catalogues. In the future, Dr Kniest says the system could be adapted for Northern Hemisphere humpback populations and other whale species.
WENDY PYPER, Information Services, AAD