Sei whales are built for open water rather than coastlines, and that is exactly where expedition itineraries put you. Crossing the Drake Passage or working through the Scotia Sea, keep an eye on calmer stretches of deep water; sei whales avoid polar and tropical extremes and semi-enclosed bays, so they turn up mid-ocean rather than tucked into fjords. They are usually solitary or in loose groups of five or six, surfacing briefly to breathe before continuing at speed, and that speed is real: this is one of the fastest whales in the world, capable of short sprints around 50 km/h.
Around South Georgia and along the broader migration corridor, sightings cluster with the austral summer, when sei whales are moving through subpolar feeding waters before their return north to warmer breeding grounds later in the year. They feed by filtering copepods, krill, and other zooplankton, and a feeding animal at the surface is often the best clue to its identity, distinguished by a dark steel-grey body and the paler, blotchy patches sometimes visible along its underside.
Two centuries of commercial whaling took a severe toll on the species, with more than 255,000 killed across the twentieth century alone, and it remains listed as endangered. Numbers are recovering, however, which is part of why a distant blow or a fast, low dorsal fin cutting through these southern waters still counts as one of the more quietly memorable sightings of a voyage.
