All animals have their preferences when it comes to the habitat in which they thrive and, while this limits distribution for most terrestrial animals, marine species often easily drift from one habitat to another. Preferences of highly mobile species for specific habitats within their vast ocean environment determines their ecotype. An ecotype refers to a population adapted to a specific habitat, which often leads to differences in their appearance. These differences, however, are not significant enough to warrant their classification as a subspecies and they are capable of interbreeding with conspecifics of a different ecotype.
Bottlenose dolphins (Tursiops truncatus) are a highly mobile cetacean species with an enormous distribution so its not surprise that you can find ecotypes even within the several Tursiops subspecies. For Bottlenose dolphins two ecotypes are defined: the small, grey coastal ecotypes that typically inhabit the coastal waters of a region and the larger, brown/grey oceanic (or offshore) ecotypes that tend to remain in offshore waters. Since Madeira is an oceanic island, it’s possible to see both ecotypes and offshores often even tag along with coastal ecotype groups. We had a few gutsy oceanics amongst the usual coastal bottlenose today and their curiosity soon spread to all the other pod members. In the evening guests even had the chance of watching the species hunt Bluefish (Pomatomus saltatrix) closer to the coast.
Ecotypes also exist amongst the Atlantic spotted dolphins (Stenella frontalis) although in their case the coastal form tends to be larger and have more spots. The spotted dolphins in Madeira’s waters are likely offshore ecotypes and arrive in large groups in the islands waters during the warmer months, making them perfect for snorkelling! Although our team was unable to find spotted dolphins for the snorkelling this morning, our zodiac managed an encounter in the afternoon with these small but charismatic cetaceans.
By Paula Thake
Sightings of the day
Ribeira Brava
09:30 Bottlenose dolphins
13:30 Bottlenose dolphins
Stenella
09:30 Bottlenose dolphins
14:00 Atlantic spotted dolphins, Bottlenose dolphins
17:00 Bottlenose dolphins
