Balaenoptera borealis Lesson
Sei or Pollack whale
Description.—Similar to the finback whale but dorsal fin larger; baleen dark; body dark blue or brownish; belly with restricted white area.
Remarks.—Recorded off-shore.
Balaenoptera acutorostrata Lacépède
Pike whale
Description.—A small whalebone whale, about 30 feet in length; body slender; head pointed; pectoral fin well developed and prominent; baleen short, white; color black above, white beneath.
Remarks.—A rare species that has been recorded from Washington.
Sibbaldus musculus (Linnaeus)
Blue whale or sulphur-bottom whale
Description.—Largest of the whales; length up to 100 feet; body slender; head flat above, rounded beneath; dorsal fin slender but prominent; baleen in two series, heavy and black; belly with numerous longitudinal ridges; color bluish black above, yellow beneath.
Remarks.—Probably uncommon off-shore.