12.10.2018 – Beauties of the ocean

The Striped dolphin (Stenella coeruleoalba) is potentially the most beautiful creature we can find in the waters surrounding Madeira. This specie is also known as Blue-white dolphin and shows unique color patterns: the back is dark greyish blue; the sides are brighter in grey and the belly as well as the ventral flanks are white. The grey and white areas are separated by dark lateral lines from the eyes all along the flanks to the tummy. More dark contours originate from the eyes towards the flippers.

But it´s not only the Striped dolphins look, those animals also move very elegant. They jump a lot whereby they show a diverse repertoire of movements in the air. Sometimes lots of dolphins leap out of the water at the same time. We were happy to witness this for several times during our trips this morning.

Compared to their close relatives, the Atlantic spotted dolphins (Stenella frontalis), the Striped dolphins are usually not as interactive and generally keep a distance to the boat. This has been different in the afternoon when some amazing jumps could be seen very close to our zodiac which is actually named after the genus of exactly those dolphin species: Stenella.

Unfortunately, from all cetaceans it seems that especially the Striped dolphins are very sensitive to marine pollution. Environmental toxins like PCB (polychlorinated biphenyl compounds) and heavy metals accumulate in their tissue. That way the immune system gets weakened and the dolphins are more vulnerable to viral infections. This can lead to mass mortalities like in the 1990s in the Mediterranean Sea.

Thanks to stricter regulations, the concentrations of those toxins are lower nowadays – an elementary achievement regarding the protections of the beauties of the ocean, the Striped dolphins.

by Jan-Christopher Fischer

Sightings of the day

Ribeira Brava

10:00 Striped dolphins

Stenella

10:00 Striped dolphins, Atlantic Spotted dolphins, Bottlenose dolphins

15:00 Striped dolphins