01.10.2018 – Blackfish

On this first day of the month of October, the Atlantic gave us a warm welcome with spectacular sightings. This morning both our boats could enjoy sightings with Short-finned pilot whales (Globicephala macrorhynchus), Bottlenose dolphins (Tursiops truncatus) and the extremely rarely sighted False orcas (Pseudorca crassidens).

All sighted cetaceans were delphinids and were encountered in close proximity to one another. The Bottlenose dolphins are the largest beaked oceanic dolphins and exist in semi-fluid aggregations, known as fission-fusion societies. Bottlenose dolphins are highly altruistic and often socialize with other delphinid species including cetaceans that are often referred to as Blackfish. The term blackfish refers to a collection of gregarious, deep-diving dolphins that boast a very different social dynamic to other oceanic dolphins and covers a total of six species including the Short-finned pilot whale and the False killer whales. The small school of Bottlenose dolphins we sighted today were spotted swimming alongside both the pilot whales and the false killer whales.

Although I enjoy encounters with all species of cetaceans during our trips, sightings with False orcas are simply unique. The name is derived from the similarity of their skulls to those of orcas (Orcinus orca). These jet-black cetaceans can reach lengths of up to 6m and are notorious for being extremely social amongst one another but also with other cetacean species. While other larger cetaceans do occasionally curiously approach our vessels during our tours, none do so with the fearless energy of the False killers.  Sightings of False orcas are extremely rare around the Madeiran archipelago with sighting statistics as low as 0.2%. The species is transient to these waters and was first recorded in the waters around the archipelago in 1997. Unfortunately, they only tend to stick around for a very short period of time, before continuing their travels through the Atlantic ocean.

Foraging advantages may have lured the animals into the waters of the Portuguese archipelago; the animals we sighted today were moving fast towards a specific target. Our spotter saw a group of skipjack (Katsuwonus pelamis), a smaller species of tuna locally known asgaiado, swimming close to the surface off the coast of Paul do Mar and the False killers were swiftly heading straight for them. The animals were moving very fast and were obviously motivated to hunt but that didn’t stop some of the individuals from riding the waves of our bow and leaping above the waters surface with their giant bodies.

We were not the only ones thrilled with todays sighting. Local scientists monitoring cetacean movements around the island were immediately informed of the False orcas by our crew. Our spotter directed the researchers to the animals, allowing them to take live samples of the ceataceans as well as tag some individuals belonging to the other species.

It was a fantastic day for our crew, our guests and for local researchers on the island. We can only humbly hope that these charismatic guests stick around for a little longer this time round.

By Paula Thake

Sightings of the day

Ribeira Brava

10:00 Bottlenose dolphins, False orcas, Short-finned pilot whales

Stenella

10:00 Bottlenose dolphins, False orcas, Short-finned pilot whales