Antarctic minke whale - Balaenoptera bonaerensis | |||||||||||||||||||||||||||||||
Taxonomy & Nomenclature
Physical Description / Field IdentificationAs in other minke whales, the
head is pointed, and there is a prominent median ridge. The dorsal
fin, situated about two-thirds of the way back from the snout tip, is
moderately tall and falcate. There are 50-70 short throat pleats,
which extend just past the flippers and 200-300 pairs of baleen
plates, most of which are black. Some of the anterior plates are
white (more white on the right side).
Antarctic minke whales are dark gray dorsally and white ventrally, with streaks and/or lobes of grayish shades on the lateral surface. Some of the streaks may extend onto the back behind the head. The distinctive white band on the flipper of Northern Hemisphere and dwarf minke whales is not usually present on Antarctic whales, although the flippers are not dark in color. The blow is generally quite conspicuous in Antarctic waters, but can be more faint at times. Adult Antarctic minke whales average about 8.5-9.0 m, and can reach 10.7 m in length. Length at birth is about 2.8 m. Maximum body weight is about 14 tons. Can be Confused WithAntarctic minke whales are generally easy to
distinguish from the larger rorquals that occur in the Antarctic
(blue, fin, and sei whales), due to their small size, pointed head,
specifics of the color pattern, and quicker movements. Although they
are generally about 2 m longer, they can be difficult to distinguish
from dwarf minke whales (B. acutorostra un-named subspecies).
The best feature is the lack of distinct white flipper band on
Antarctic minkes.
DistributionAntarctic minke whales occur in coastal and offshore areas of the
Southern Hemisphere, and are found from at least 10°S south to
the ice edges. They tend to be more polar than common minke whales,
and most spend their summers in waters around the Antarctic
continent.
Ecology and BehaviorAlthough groups elsewhere are generally much
smaller, aggregations in the Antarctic may contain hundreds of
animals. Whales migrate to the Antarctic for the summer for
feeding, and to more moderate climates in the winter for breeding.
Although they are not as aerially active as some other whales, minke
whales do occasionally breach and spyhop.
Antarctic minke whales exhibit similar life history parameters to those of Northern Hemisphere minkes. Attainment of sexual maturity is attained at ages of 7-8 years for females and 8 years in males. Feeding and PreyAntarctic minke whales eat mostly krill, although they
do occasionally feed on small schooling fishes. They are lunge
feeders.
Threats and StatusLarge numbers of minke whales (probably mostly
Antarctic minkes) have been killed in Antarctic waters in the past
100 years or so. Japan’s so-called “scientific whaling”
focuses mainly on this species, which is still quite abundant in
Southern Hemisphere waters, with several hundred thousand animals
thought to remain.
IUCN
& ESA Status: Lower Risk/Conservation Dependent (IUCN); Not
Listed (ESA).
LinksN/A
ReferencesARNOLD, P., H. MARSH, AND G. HEINSOHN. 1987. The occurrence of two forms of minke whales in east Australian waters with a description of external characters and skeleton of the diminutive or dwarf form. Scientific Reports of the Whales Research Institute 38:1-46. BROWNELL ET AL. 2000. Worldwide taxonomic status… HORWOOD, J. 1990. Biology and exploitation of the minke whale. CRC Press. PERRIN, W.F. AND R. L. BROWNELL. 2002. Minke whales Balaenoptera acutorsotrata and B. bonaerensis. Pp. 750-754 in W. F. Perrin, B. Wursig and J. G. M. Thewissen, eds. Encyclopedia of marine mammals. Academic Press. STEWART, B. S., AND S. LEATHERWOOD. 1985. Minke whale Balaenoptera acutorostrata Lacepede, 1804. 91-136 in S. H. Ridgway and R. Harrison, eds. Handbook of marine mammals, Vol. 3: Sirenians and the baleen whales. Academic Press. |
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