Sei whales are the third largest species of baleen whale and can be seen infrequently around `Madeira.

Sei Whale

Balaenoptera borealis

The Sei whale is the third largest of the baleen whale species and known as the fastest swimmer as they can reach speeds of up to 50 km/hr over short distances. Sei and Bryde’s whales are very similar in appearance and can be difficult to distinguish. While the Sei whale is infrequently seen on Madeira whale watching tours, we typically encounter more Sei whales during the summer and fall months.

Information on the Sei whale, the 3rd largest of the baleen whales.

Species Information

Sei whales are large baleen whales that we see typically during the summer months in Madeira.
  • Length: up to 18 meters

  • Weight: up to 45,000 kg

  • Lifespan: up to 60 years

  • Diet: plankton, krill, small fish and cephalopods

Data on the sightings of Sei whales around the island of Madeira.


Sei whale sightings are more common during the summer months and usually end up in a debate. They are so similar to Bryde’s whales, the most commonly seen baleen whale around Madeira, that usually it takes a very good photo of the rostrum to decide what species we are looking at! Bryde’s whales have 3 ridges on their rostrum (in front of the blowhole) and Sei whales do not. When we do encounter a Sei whale is it usually foraging and repeats dive intervals every 7 minutes followed by 3-4 breath cycles.