The ocean was calm and clear as our traditional boat steered three nautical miles out to meet a group of Atlantic spotted dolphins (Stenella frontalis). The dolphins were being their usual playful, interactive selves and shot to and fro around the Ribeira Brava as our enchanted guests smiled in admiration. As a second boat approached the area we moved further West to meet yet another group of spotted dolphins that showed equal interest in our colourful vessel and began gliding through the waves around the boat. At such close range individual characteristics of the animals become more apparent. We managed to spot a mature adult with a noticeable injury on its tail fin and another individual with very defined countershading.
Countershading is an abundant camouflage pattern in marine animals where the belly is lightly coloured while the dorsal body parts are darker in colour. Countershading is thought to grant the animals stealthy advantages as they forage for prey and is is a colour scheme possessed by all species of dolphin, acting as a base for the characteristic coloration of each and every species. The countershading was particularly distinct on this specific juvenile dolphin, whose dorsal part was almost uniformly dark grey with a clear line separating it from the bright white belly side. The individual with the high contrast countershading also enabled us to recognise this specific group of spotted dolphins, since we had encountered the same individual during a snorkelling tour and a Stenella whale-watching tour in the previous days.
By Paula Thake
Sightings of the day
10:00 Atlantic spotted dolphins