Sei whale

Appearance

The sei whale's body is typically a dark steel grey with irregular light grey to white markings on the ventral surface, or towards the front of the lower body. Its skin is often marked by pits or wounds, that after healing become white scars. It has a tall, sickle-shaped dorsal fin that ranges in height from 38–90 cm (15–35 in) and averages 53–56 cm (21–22 in), about two-thirds of the way back from the tip of the rostrum.

Adults have 300–380 ashy-black baleen plates on each side of the mouth, up to 80 cm (31 in) long.

Range and habitat

Sei whales live in all oceans, although rarely in polar or tropical waters. The difficulty of differentiating them at sea from their close relatives, Bryde's whales and in some cases from fin whales, creates confusion about their range and population, especially in warmer waters where Bryde's whales are most common. In the North Atlantic, its range extends from southern Europe or northwestern Africa to Norway, and from the southern United States to Greenland.

Pins are Wikidata “endemic to” fields. Orange dots, when present, are GBIF occurrence tiles — survey bias included.

Diet and breeding

During the breeding period, a mating pair will remain together. The sei whale migrates annually from cool, subpolar waters in summer to temperate, subtropical waters in winter with a lifespan of 70 years.

It is a filter feeder, with its diet consisting primarily of copepods, krill, and other zooplankton. It is typically solitary or can be found in groups numbering half a dozen.

In crisis

The Northern Hemisphere population is listed under CITES Appendix II, that indicates they are not threatened with extinction, while the Southern Hemisphere population is listed under CITES Appendix I, indicating that they are threatened and are given the highest levels of protection. Northern Hemisphere populations are listed in CITES Appendix II, indicating they are not immediately threatened with extinction, but may become so if they are not listed. As of 2018, the global population is estimated to be 50,000 mature individuals, with an increasing population trend.

As of 1983, around 10,000 whales were estimated in the Southern Hemisphere, and by 2011, approximately 35,000 individuals inhabited the North Pacific. Nova Scotia's 1977 population estimates were between 1,393 and 2,248, with a minimum of 870.

Sei whale is Endangered on this catalog because that is the IUCN category stored on Wikidata. Confirm the official criteria and any later count on iucnredlist.org.

Sources

Written for this catalog from the English Wikipedia article on Sei whale, Wikidata item Q185097. Family and order context is original field-guide writing about the group, not a copied assessment of this one species. Wikipedia text is CC BY-SA. Not an IUCN assessment. Counts, when quoted, can change — confirm them on the recovery programme and on iucnredlist.org.