Dorsal fins are very important for both cetaceans and whale enthusiasts! The dorsal fin along with the animals flippers and caudal fin ensure smooth movement through the water and allow the animal to maintain direction and stability whilst swimming. They also happen to be one of the first body parts visible the surface during most cetacean sightings and therefore play an important role when incomes to tracking these animals down for an observation.
Dorsal fins also are scientifically important; markings along these falcate-shaped fins often allow the identification of individual animals, giving scientists a lot of insight into the population dynamics of the species. This non-invasive method is known as photo-identification and has also helped scientists in Madeira gain a better understanding of the species visiting the islands waters.
One of the best studied species occurring in Madeira are the Short-finned pilot whales (Globicephala macrorhynchus), large peaceful dolphins that were encountered on both our tours today. During the afternoon tour we had even approached a group of these animals, one of which that had just been tagged using a satellite tag by a group of scientists that were conducting field work. Since these animals tend to form stable matriarchal units, our crew made sure to take some pictures of all the animals dorsal fins before heading off to a sighting with some cheeky Atlantic spotted dolphins (Stenella frontalis) that playfully leapt around our zodiac. Dorsal fin pictures have also helped local scientists identify some individual Bottlenose dolphins (Tursiops truncatus) and the most obviously marked animals can often even be identified by our crew at sea. On todays morning trip we met a group where we could make out quite a few familiar dorsal fins, particularly on one older dolphin.
As if all these sightings weren’t enough on this “fin-tastic” Monday, the first dorsal fins we saw today belonged to the second largest animal on our planet. As we left Calheta this morning, we encountered a small group of Fin whales (Balaenoptera physalus) heading for Western waters, who even showed enough curiosity to approach the bow of our boat granting our guests a closer look at their enormous bodies! What an incredible day!
By Paula Thake
Sightings of the day
10:00 Bottlenose dolphins, Fin whales, Short-finned pilot whales
15:00 Atlantic spotted dolphins, Short-finned pilot whales