16.05.2019 – Seasonal shifts

The beautiful Short-beaked common dolphins (Delphinus delphis) decorated the waters of the Atlantic today during both our tours. These charismatic dolphins will soon migrate to cooler waters, with only a handful of animals remaining in the waters around the island during the warmer months. The large populations of these small delphinids will be replaced by the presence of another abundant and seasonal species of dolphin, the Atlantic spotted dolphins (Stenella frontalis).

The seasonal distribution of both these species is obviously in some way related to the changing temperatures in the ocean and, recently, scientists on the island released a paper modelling the possible effects of climate change on the populations of different cetaceans visiting Madeira. Oddly enough, the commons, the spotted and the island-associated Bottlenose dolphins (Tursiops truncatus) showed a surprisingly low vulnerability in contrast to other species. Reasons for this may be the high variability in residency on the side of the Bottlenose and the low exposure to current climate effects of the seasonal dolphins due to their constant migrations. However, changes in ocean physics could affect the availability of their prey in certain areas, including Madeira, and may cause shifts in these seasonal migrations.

For now, this seasonal “shift changeover” between these two species can be expected every year and while we are always sad to temporarily say goodbye to one species, we are happy to welcome the other.

By Paula Thake

Sightings of the day

Ribeira Brava

14:30 Short-beaked common dolphins

Stenella

10:00 Short-beaked common dolphins