Balaenoptera borealis

SIZE: Male- 12-15m, Female- 13-16m

Very similar to the fin whale, the sei whale is one of the least-studied baleen whale species. It is the third-largest whale species, smaller and more slender than the fin whale, with a taller, more curved dorsal fin. Like other baleen whales, sei whales feed by filtering small prey through their baleen plates, including plankton, krill and small schooling fish.

Sei whales are mainly found offshore and their seasonal movements can be unpredictable, so they are relatively rare visitors to the fjords around Iceland. They have nevertheless been encountered several times on our tours in Breiðafjörður. Their presence can vary considerably from year to year, and there is still much we do not know about their distribution and behaviour.

Sei whales have a long history of being hunted by commercial whalers. Once blue and fin whale populations had declined and whalers developed motor boats and exploding harpoons, whaling fleets increasingly targeted sei whales, and their global population was heavily reduced during the 20th century. Commercial hunting largely ended by the late 20th century, and the species is now classified as Endangered by the IUCN.