23.09.2018 – More than just a picture

Both our boats had to venture far towards the east of the island to find animals, a rather unusual situation for our crew. I was on board the Stenella with a lovely group of interested guests who seemed to enjoy every minute of the ride; from the smooth cruise along the coast where they had the chance of admiring the island from a different perspective, to the swift maneuvers of our captain over the higher swell in the east up to the lovely encounters with the animals.

Near Cabo Girao, our spotter was able to locate a small group of Bottlenose dolphins (Tursiops truncatus) before directing us further east off the coast of Funchal to a small group of Sperm whales (Physeter macrocephalus). It was a short but spectacular sighting; after some time the animals lifted their flukes to descend into the depths.

Bottlenose dolphins and Sperm whales belong to the best documented cetacean species around Madeira. Using photo-id catalogues constituted by photos from scientific field work as well as those contributed by companies like Lobosonda, researchers are able to identify individual animals using certain characteristic features. Photo-identification has been used to identify individuals within animal populations since the 60s and has proven to be a reliable, non-invasive tool to obtain data on community structures and thereby enhance conservation efforts for different species. Of course, optimized results can only be achieved if a trustworthy, standardized protocol for each species is accomplished.

Thankfully, several cetacean species do indeed have characteristic features which allow the recognition of an individual amongst its fellow peers. Adult Bottlenose dolphins, like other delphinids, can be distinguished individually through the contours on their dorsal fins. This relatively stable feature has been used in photo-id catalogues since the 70s often in combination with other natural markings. Sperm whales, highly migratory toothed whales with a dorsal hump not a dorsal fin, are best identified through their lifted fluke before a deep dive. This method has been used to monitor species populations worldwide and has allowed local biologists to identify around 200 individuals around the Madeiran archipelago.

Apart from the rather well-known features used for identification, scientists continue to expand and develop this useful technique of monitoring cetaceans. In the Northwest Mediterranean, for instance, scientists also analyse natural pigmentation on the flanks of Sperm whales to identify each of the animals. It’s an exciting field and is particularly intriguing for whale-watching companies because it allows us to offer a steadfast contribution to the conservation of the magnificent animals we are lucky to admire out on the ocean every single day.

By Paula Thake

Sightings of the day

Ribeira Brava

10:00 Bottlenose dolphins

Stenella

12:00 Bottlenose dolphins, Sperm whales, Loggerhead turtle