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Sei Whale

Balaenoptera borealis

Summary 3

The Sei Whale (pronounced SAY) (Balaenoptera borealis) is a baleen whale, the third-largest rorqual after the blue whale and the fin whale. It can be found worldwide in all oceans and adjoining seas, and prefers deep off-shore waters. The sei whale migrates annually from cool and subpolar waters in summer to temperate and subtropical waters for winter.

Length 60-70 feet (18-21 meters)
Weight 40,000-60,000 lb (18,000-27,000 kg)

The sei whale has a typical rorqual shape with a long torpedo shaped body. This allows these animals to reach very fast swimming speeds. Sei whales feed on small plankton in the water such as copepods and krill, unlike other rorqual whales, sei whales do not very deep and swim very close to the surface. It is possible to track their path under the water by the swirling "fluke prints" they leave behind.

The Sei whale looks very similar, and is closely related to the Bryde's whale, in fact for a long time it was believed they were one species. These two species can be told apart by the ridges that run from the blow hole to the snout, the Sei whale only has one while the Bryde's whale has three.

Population and Conservation Status 4

Global Population is 40,000-60,000

The Sei whale is Endangered

Threats 5

The sei whale was not a traditional target of the whaling industry, but it began to be exploited after the blue, fin and humpback stocks became depleted and protected. This species was relentlessly hunted in the 1960s and 70s, before the International Moratorium on Commercial Whaling came into effect in 1986.

Today, the sei whale is protected from hunting in most of its range however it is still harvested by some whaling nations. The species is vulnerable throughout its range to human impacts on the marine environment, including pollution, excess noise, and impacts from climate change.

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Sources and Credits

  1. (c) tegmort, some rights reserved (CC BY-NC), uploaded by tegmort
  2. (c) WoRMS for SMEBD, some rights reserved (CC BY-NC-SA), http://images.marinespecies.org/resized/49206_balaenoptera-borealis.jpg
  3. Adapted by Bodacious Dream - Dave Rearick from a work by (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Balaenoptera_borealis
  4. Adapted by Bodacious Dream - Dave Rearick from a work by (c) WoRMS for SMEBD, some rights reserved (CC BY), http://eol.org/data_objects/17825714
  5. Adapted by Bodacious Dream - Dave Rearick from a work by (c) Wildscreen, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/2605700
  6. (c) Bodacious Dream - Dave Rearick, some rights reserved (CC BY-SA)

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