FIN WHALE (B) 



Balaenopteraphysalus (Linnaeus 1758) 



Other Common Names 



Finback whale, finner, razorback, common rorqual. 



Description 



Fin whales have been reported to reach 79 feet (24 m). 

 Females are slightly larger than males of the same age. 



The back is distinctly ridged towards the tail, prompting 

 the common name "razorback" whale. 



The rostrum is narrower and more V-shaped than that of 

 the blue whale and has the same sort of single distinctive head 

 ridge. The top of the head is flat, though slightly less than 

 that of the blue whale. 



The dorsal fin is up to 24 inches (61 cm) tall; angled less 

 than 40° on the forward margin, located slightly more than 

 one-third forward from the tail, and appears on the surface 

 shortly after the blow. 



All individuals are dark gray to brownish black on the 

 back and sides with none of the mottling present on blue 

 whales and are rarely as heavily scarred as sei whales. Along 

 the back, just behind the head, there is a grayish-white 

 chevron, with the apex along the midline of the back and the 

 arms of the chevron oriented posteriorly, which is sometimes 

 distinctive and may be visible as the animals surface to 

 breathe. The undersides, including the undersides of the 

 flukes and flippers, are white. On the head, the dark 

 coloration is markedly asymmetrical, reaching farther down 

 on the left than on the right side. The right lower lip, 

 including the mouth cavity, and the right front baleen 

 (approximately one-fifth to one-third) are yellowish white. 

 Occasionally the right upper lip is also white. The remainder 

 of the plates on the right side and all those on the left side are 

 striped with alternate bands of yellowish white and bluish 

 gray. The fringes of the plates are brownish gray to grayish 

 white. 



Natural History Notes 



Fin whales are one of the most common baleen whale spe- 

 cies in the world and constitute a major portion of the whaling 

 catch. They are reportedly one of the fastest of the big whales 

 (sei whales may be slightly faster) possibly reaching burst 

 speeds in excess of 20 knots, and were not an important com- 

 mercial species until the comparatively recent development of 

 fast catcher boats and the depletion of blue whale stocks. 



A fin whale's blow can be from 15 to 20 feet (4.6 to 6.1 m) 

 tall and has been described as an inverted cone or an 

 elongated ellipse. 



Fin whales dive to at least 755 feet (230. 1 m). This depth is 

 probably deeper than that of either blue or sei whales, a 

 factor usually reflected in differences among the surfacing, 

 blowing, and diving characteristics of these three species. 

 When they are moving leisurely at the surface, fin whales 

 expose the dorsal fin shortly after the appearance of the 

 blowholes, slightly later than that of the sei whales. When 

 they are surfacing from a deeper dive, however, they surface 

 at a steeper angle, blow, submerge the blowholes, and then 



arch the back and dorsal fin high into the air before beginning 

 another long dive. In this species it can be generally stated 

 that the maximum amount of the back in the area of the dorsal 

 fin which is exposed above the surface as the animal sounds is 

 approximately 2 times the height of the dorsal fin. Fin whales 

 do not show their tail flukes when beginning a dive. 



Unlike blue or sei whales, fin whales do breach on 

 occasion. When they do leap clear of the water, fin whales 

 usually reenter with a resounding splash, like that made by 

 humpback and right whales and not smoothly, head first, as 

 minke whales often do. 



Fin whales are sometimes found singly or in pairs but 

 more often occur in pods of six or seven individuals and many 

 pods consisting of as many as 50 animals may be concentrated 

 in a small area. 



Fin whales calve and breed in winter, mostly in temperate 

 waters. 



Atlantic fin whales eat a wide variety of foods, including 

 krill, capelin, squid, herring, and lanternfish. 



May Be Confused With 



Fin whales may be confused with blue whales, sei whales, 

 and, in the southernmost portion of their range, with Bryde's 

 whales. They may be distinguished from the blue whales by 

 differences in overall coloration, coloration and shape of the 

 head, and the size, position, and time of appearance of the 

 dorsal fin at the surface (see p. 19). After close examination 

 they may be distinguished from Bryde's whales by the 

 presence of three ridges along the head (of the Bryde's whale) 

 and by the smaller, more sharply pointed falcate dorsal fin of 

 the Bryde's whale (see Fig. 31). They may be distinguished 

 from sei whales in the following similar ways: 



Fin Whale 



Sei Whale 



DORSAL FIN 



Slightly falcate, forms angle 

 of less than 40° with back 

 slightly more than one-third 

 forward from tail. 



Sharply pointed and falcate; 

 forms angle of greater than 

 40° with back well more than 

 one-third forward from tail. 



SURFACING BEHAVIOR 



Usually rise obliquely so top 

 of head breaks surface first; 

 after blowing, animal arches 

 its back and rolls forward 

 exposing the dorsal fin on the 

 long dive; on sounding, the 

 maximum amount of back in 

 the area of the dorsal fin 

 which is exposed is approxi- 

 mately 2 times the height of 

 dorsal fin. 



Primarily skimmer feeders; 

 usually rise to surface at 

 shallow angle so that dorsal 

 fin and head are visible 

 almost simultaneously; when 

 starting the long dive does 

 not usually arch the back as 

 much as the fin whale; on 

 sounding, the maximum 

 amount of back in the area of 

 the dorsal fin which is 

 exposed is approximately 1 

 times the height of the dorsal 

 fin. 



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