Description
Balaenoptera borealis
Date 1987
Source Cetaceans of the Channel Islands National Marine Sanctuary https://archive.org/details/cetaceansofchann00leat
Author NOAA United States. National Marine Fisheries Service
Source: https://commons.wikimedia.org/wiki/File:Balaenoptera_borealis.jpg

The sei whale (Balaenoptera borealis) is a baleen whale, the third-largest rorqual after the blue whale and the fin whale. It inhabits most oceans and adjoining seas, and prefers deep offshore waters. It avoids polar and tropical waters and semienclosed bodies of water. The sei whale migrates annually from cool and subpolar waters in summer to winter in temperate and subtropical waters.