29.08.2022 – Squid game

The end of August and beginning of September marks the climax of the potas season here in Madeira, a deep-sea squid species that is a favourite prey for many toothed whales. These cephalopods are usually found at depths of around 200m but at this time of the year, they migrate to the surface at night to feed along with several other marine animals. This nocturnal migration attracts a number of toothed whales into the waters of the archipelago including several of the more elusive species.

In the morning our sightings were dominated by Bottlenose Dolphins (Tursiops truncatus), who in their usual coast-guard like manner were found within 3 nautical miles off the coastline. Our team searched far and wide for Atlantic spotted dolphins (Stenella frontalis) for our snorkelers but the small cetaceans decided to enter the Southwestern waters after midday…along with a lot of other interesting visitors.

Both spotted and bottlenose dolphins were seen by both our boats in the afternoon but flexible search range of our zodiac allowed the team to see a few of the rarer cetaceans here in Madeira. Pygmy sperm whales (Kogia breviceps), a shy and poorly understood cetacean, were moving discreetly through the glassy ocean. Like their larger taxonomic cousins, the Sperm whales (Physeter macrocephalus), they have a spermaceti organ but unlike the toothed whale giants very little is known about them and their social lives. Most of what we know comes from carcasses washed ashore and we know that they love to feed on cephalopods.

The same goes for their equally shy toothed whale relatives, the beaked whales. Today a Mesoplodon species emerged at the glassy surface and breached several times into the air. The on-board guide, Fatima, managed some fantastic photos which she forwarded to scientists for identification.

For the last years, our team has been trying to find True’s beaked whales (Mesoplodon mirus) in the waters of Madeira, a rare species of beaked whale that is likely to occur here. For now, the feedback from scientists has confirmed the animals as Gervais beaked whales (Mesoplodon europaeus) but what we know for sure is that we can definitely keep a sharper lookout for new species at this time of the year!

By Paula Thake

Sightings of the day

Ribeira Brava

10:00 Bottlenose Dolphins

15:00 Atlantic spotted dolphins, Bottlenose dolphins

Stenella

09:30 Bottlenose dolphins

14:00 Atlantic spotted dolphins, Bottlenose dolphins, Pygmy sperm whale

17:00 Atlantic spotted dolphins, Bottlenose dolphins, Pygmy sperm whale, Unidentified beaked whale