21.07.2019 – Stenella sundays

The final day of this eventful week was spent in the company of some lovely guests and the two species of the small dolphin genus Stenella, that both frequently visit the waters of the archipelago. The Atlantic spotted dolphins (Stenella frontalis) were encountered on all tours today while the Striped dolphins (Stenella coeruleoalba) were additionally seen this afternoon. Both these dolphins are incredibly impressive but they couldn’t be more different in their reaction to boats.

The spotted dolphins are extremely interactive, probably the most interactive of all the cetacean species visiting the islands waters. They virtually dart words us when we enter the sighting area and never fail to make our guests smile with their cheeky leaps and effortless bowriding. The curiosity of this species isn’t only a pleasure to experience, it also has helped scientists learn a great deal about the social life and communication of dolphins. Dr. Denise Herzing, a personal heroine of mine and a renowned biologist, has been swimming with a resident pod of these dolphins for over 30 years. These encounters also bore fruit; Herzing is the first scientist to establish two-way communication with these animals, with the animals mimicking whistles designed by Herzing to signal their intentions. This is a revolutionary method of understanding more about dolphins since most studies in the past were done on animals in captivity. 

The pelagic Striped dolphins enjoy a worldwide distribution but remain an enigma in some study areas due to their highly evasive behaviour at sea. Their timid reaction to boats around Madeira may also be due to the fact that we mainly encounter small nursery groups around the island, containing tiny almond-shaped calves. Out in the open ocean, these gorgeous dolphins form gigantic schools containing hundreds of animals that are typically referred to as “super-pods”. Once in a while, particularly when they are in the company of a more interactive species such as the equally decorative Short-beaked common dolphins (Delphinus delphis), the Striped set aside their trust issues and approach our boats.

However a dolphin may react towards us at sea, we are grateful to have them around and enjoy making our own behavioural observations together with our guests. For those interested in Herzings work, here is a link to a TED talk by the acclaimed scientist where she explains the research conducted by her team in the Bahamas:

https://www.youtube.com/watch?v=CQ5dRyyHwfM

By Paula Thake

Sightings of the day

Ribeira Brava

09:00 Atlantic spotted dolphins

15:00 Atlantic spotted dolphins, Striped dolphins

Stenella

09:00 Atlantic spotted dolphins

15:30 Atlantic spotted dolphins, Striped dolphins