Fin Whale - Balaenoptera physalus

Fin Whale
Balaenoptera physalus

Other Names: Finback, Finner, Common Rorqual, Razorback, Herring Whale

Habitat: Offshore and Inshore

Status: Locally Common

Population: c.120,000

Threats: Pollution

Group Size: 3-7, 100 or more may gather at good feeding grounds

Fin Position: Far behind center

Newborns: 19'3/4"-21'1/2"(6m-6.5m), c.2 tons

Adults: 59'-72'1/4"(18m-22m), 30-80 tons

Diet: Krill or other crustaceans, fish, and occasionally squid or octopus

Baleen: 260-480 baleen plates on each side

Description

Dorsal fin:

- small, falcate dorsal fin slopes backward (variable)
- pointed tip (variable)
- may have rounded tip
- shape and angle of fin highly variable

Flukes:

- white underside
- slightly concave trailing edges may be notched or frayed
- distinct notch in middle
- broad, slightly triangular flukes

Flippers:

- slender, relatively short flippers
- white underside
- pointed tips

Head:

- prominent splashguard in front of blowholes
- broad, flat rostrum, but less than in blue whale
- front baleen plates white on right side
- all baleen plates dark gray on left side
- throat grooves
- right side of head white, left side is dark gray

Head (from above):

- 2 distinct blowholes
- single longitudinal ridge extends from blowholes to close to tip of snout
- distinctive V-shaped head with narrow, pointed snout

Other characteristics:

- tip of rostrum level (no downward turn)
- variable grayish white chevron behind head on each side (more prominent on right)
- silvery gray, dark gray, or brownish black body color
- long, streamlined body
- distinct ridge from dorsal fin to flukes, hence alternative name "Razorback"
- thick tail stock
- body free of molting
- body usually shows very little scarring
- white underside
- 56-100 throat grooves, usually end at or behind navel
- lower "lip" dark on left side but white on right

Behavior

- almost impossible to judge when it will surface or how far away
- surfacing motion depends on whether the whale is moving leisurely at the surface or surfacing from a deep dive
- it typically bows 2 to 5 times, at intervals of 10 to 20 seconds, before diving for 5 to 15 minutes
- dives to depths of at least 775 ft (230 m)
- asymmetrical pigmentation may be linked with the way the whale swims on its right side while feeding
- sometimes breaches clear of the water
- fast swimmer, capable of reaching speeds over 19 mph (30 km/h)
- more commonly seen in small groups than other rorqual whales

Distribution

- worldwide distribution, but most common in temperate waters and in the southern hemisphere
- least common in the tropics
- only rorqual commonly found in the Mediterranean
- there are probably 3 geographically isolated populations: in the North Atlantic, North Pacific, and southern hemisphere
- some populations may migrate between relatively warm low latitudes in summer
- certain lower latitude populations, such as in the Gulf of California (Sea of Cortez), Mexico, seem to be resident year-round
- usually occurs in offshore waters but may be seen close to shore in areas where water is deep enough

e-mail questions, comments, and/or suggestions to
wcrc@sci.tamucc.edu

Internet Coordinator: Candice Orca Mottet

e-mail questions, comments, and/or suggestions to wcrc@sci.tamucc.edu

e-mail questions, comments, and/or suggestions to
wcrc@sci.tamucc.edu