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Balaenoptera musculus

(Linnaeus, 1758)

Blue Whale

G3Vulnerable (G3G4) Found in 2 roadless areas NatureServe Explorer →
G3VulnerableGlobal Rank
EndangeredIUCN
Identity
Unique IDELEMENT_GLOBAL.2.101880
Element CodeAMAGH01040
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVertebrate Animal
IUCNEndangered
CITESAppendix I
Endemicoccurs (regularly, as a native taxon) in multiple nations
KingdomAnimalia
PhylumCraniata
ClassMammalia
OrderCetacea
FamilyBalaenopteridae
GenusBalaenoptera
COSEWICE
Other Common Names
Ballena Azul (ES) Rorqual bleu (FR)
Concept Reference
Wilson, D. E., and D. M. Reeder (editors). 1993. Mammal species of the world: a taxonomic and geographic reference. Second edition. Smithsonian Institution Press, Washington, DC. xviii + 1206 pp. Available online at: http://www.nmnh.si.edu/msw/.
Conservation Status
Rank MethodExpertise without calculation
Review Date2016-04-04
Change Date1999-12-01
Edition Date2011-04-06
Edition AuthorsHammerson, G., T. French, and K. Willson
Range Extent>2,500,000 square km (greater than 1,000,000 square miles)
Number of OccurrencesUnknown
Rank Reasons
Large range in the Pacific, Atlantic, and southern oceans; low population numbers, far below historical levels, due to whaling; current population more than 10,000, with some populations increasing.
Range Extent Comments
Occurs throughout the world's oceans. Three major breeding groups: North Pacific, North Atlantic, and Antarctic; perhaps a separate breeding population in the Indian Ocean. Seen with some regularity in deep coastal canyons off central and southern California, far inside the Gulf of St. Lawrence, and in the Denmark Strait. See IUCN (1991) for further details. For all practical purposes the Northern Hemisphere and Southern Hemisphere stocks do not mix (IUCN 1991). Subspecies BREVICAUDA (pygmy blue whale) is known mainly from subantarctic waters of the Indian Ocean and southeast Atlantic; reported also from other areas such as the northern Indian Ocean and off western South America.
Occurrences Comments
Unknown; difficult to define element occurrences.
Threat Impact Comments
Historically over-harvested. Today the species may be negatively affected by food-chain alterations resulting from commercial fishing/whaling (J. Barlow, pers. comm., 1995). There is concern among some biologists that underwater sound waves, such as those to be transmitted as part of the Acoustic Thermometry of Ocean Climate project (see Schmidt, 1994, Science 264:339-340), may detrimentally impact marine mammals; all agree that more information is needed on the impact of noise on marine mammals.
Ecology & Habitat

Description

A very large (the largest living animal) baleen whale; body is mottled bluish gray; head is flat in front of the paired nostrils, broad and nearly U-shaped in dorsal view, with a single median ridge that extends forward from the raised area in front of the nostrils (ridge does not quite reach tip of snout); dorsal fin, located in the last quarter of the back, is very small; throat has 55-68 longitudinal grooves; belly may appear yellowish due to diatom accumulations; flipper are long and slim; baleen is black; potential maximum length is over 30 m, with the largest females averaging slightly longer than the largest males (Leatherwood and Reeves 1983).

Diagnostic Characteristics

Differs from the fin whale in the mottled blue-gray body coloration, symmetrical lower lip coloration, broader U-shaped rather than V-shaped snout, baleen that is black rather than gray to white, and the smaller dorsal fin that is located farther toward the posterior. Differs from the sei whale in the much shorter dorsal fin that is located much farther toward the posterior (Leatherwood and Reeves 1983).

Habitat

Mainly pelagic; generally prefers cold waters and open seas, but young are born in warmer waters of lower latitudes.

Ecology

Usually solitary or in pairs or threes; may congregate in good feeding areas.

Reproduction

Mates May-September in the Northern Hemisphere. Gestation is reported as 11 or 12 months. Adult females bear one calf every 2-3 years. Young are weaned in about 8 months. Females reach sexual maturity in about 10 years. Maximum lifespan is uncertain; reportedly only about 20 years or up to 80-90 years.
Other Nations (2)
CanadaN1N
ProvinceRankNative
Nova ScotiaSNRNYes
British ColumbiaS1NYes
QuebecS1Yes
United StatesN1
ProvinceRankNative
MaineSNRYes
MassachusettsS1Yes
New YorkSNAYes
FloridaSNRYes
OregonSNAYes
New JerseyS1Yes
HawaiiSNRYes
AlaskaS2Yes
TexasSHYes
South CarolinaS2Yes
CaliforniaSNRYes
Rhode IslandSNRNYes
MarylandS1Yes
Threat Assessments
ThreatScopeSeverityTiming
5 - Biological resource usePervasive (71-100%)Extreme or 71-100% pop. declineInsignificant/negligible or past
5.4 - Fishing & harvesting aquatic resourcesPervasive (71-100%)Extreme or 71-100% pop. declineInsignificant/negligible or past
7 - Natural system modificationsUnknownUnknownHigh (continuing)
7.3 - Other ecosystem modificationsUnknownUnknownHigh (continuing)
9 - PollutionPervasive (71-100%)UnknownHigh (continuing)
9.6 - Excess energyPervasive (71-100%)UnknownHigh (continuing)
11 - Climate change & severe weatherPervasive - largeUnknownModerate - low
11.1 - Habitat shifting & alterationPervasive - largeUnknownModerate - low

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Roadless Areas (2)
California (2)
AreaForestAcres
CamuesaLos Padres National Forest8,209
MonoLos Padres National Forest28,141
References (28)
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  2. Banfield, A. W. F. 1974. The mammals of Canada. University of Toronto Press, Toronto, Canada. 438 pp.
  3. Barnes, L. G., and S. A. McLeod. 1984. The fossil record and phyletic relationships of gray whales. Pages 3-32 in Jones, M. L., et al., eds. The gray whale. Academic Press,Orlando, Florida.
  4. Baskin, Y. 1993. Blue whale population may be increasing off California. Science 260:287.
  5. Bradley, R.D., L.K. Ammerman, R.J. Baker, L.C. Bradley, J.A. Cook. R.C. Dowler, C. Jones, D.J. Schmidly, F.B. Stangl Jr., R.A. Van den Bussche and B. Würsig. 2014. Revised checklist of North American mammals north of Mexico, 2014. Museum of Texas Tech University Occasional Papers 327:1-28. Available at: http://www.nsrl.ttu.edu/publications/opapers/ops/OP327.pdf
  6. Falklands Conservation. 2000. Falkland Islands wildlife. Falklands Conservation. http://www.falklands-nature.demon.co.uk/wildlife/chklst.html
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  11. IUCN (World Conservation Union). 1991. Dolphins, Porpoises and Whales of the World: the IUCN Red Data Book. M. Klinowska (compiler). IUCN, Gland, Switzerland, and Cambridge, United Kingdom. viii + 429 pp.
  12. Jones, J. K., Jr., D. C. Carter, H. H. Genoways, R. S. Hoffman, D. W. Rice, and C. Jones. 1986. Revised checklistof North American mammals north of Mexico, 1986. Occas. Papers Mus., Texas Tech Univ., 107:1-22.
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  15. Leatherwood, S., and R. R. Reeves. 1983. The Sierra Club handbook of whales and dolphins. Sierra Club Books, San Francisco. 302 pp.
  16. Mate, B. R., B. A. Lagerquist, and J. Calambokidis. 1999. Movements of North Pacific blue whales during the feeding season off southern California and their southern fall migration. Marine Mammal Science 15:1246-1257.
  17. Matthews, J.R. and C.J. Moseley (eds.). 1990. The Official World Wildlife Fund Guide to Endangered Species of North America. Volume 1. Plants, Mammals. xxiii + pp 1-560 + 33 pp. appendix + 6 pp. glossary + 16 pp. index. Volume 2. Birds, Reptiles, Amphibians, Fishes, Mussels, Crustaceans, Snails, Insects, and Arachnids. xiii + pp. 561-1180. Beacham Publications, Inc., Washington, D.C.
  18. National Marine Fisheries Service (NMFS). 1985. Annual Report 1984/1985, Marine Mammal Protection Act of 1972.
  19. National Marine Fisheries Service (NMFS). 1987. Marine Mammal Protection Act of 1972. Annual Report 1986/87.
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  26. Thompson, P.O. and W.A. Friedl. 1982. A long term studyof low frequency sounds from several species of whales off Oahu, Hawaii. Cetology 45:1-19.
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  28. Wilson, D. E., and D. M. Reeder (editors). 2005. Mammal species of the world: a taxonomic and geographic reference. Third edition. The Johns Hopkins University Press, Baltimore. Two volumes. 2,142 pp. [As modified by ASM the Mammal Diversity Database (MDD) at https://www.mammaldiversity.org/index.html]