Balaenoptera musculus
Scientific Name:-
Balaenoptera musculusCommon Name:-
Blue Whale
Malayalam Name:-
Neelathimingalam
Category:-
Mammals
Status:-
Classified as "Endangered” by the IUCN and listed in Appendix I of CITES and Conservation of Migratory Species of Wild Animals (CMS). Listed in Schedule II of Indian (Wildlife) Protection Act.
Description:-
Blue whales are bluish grey dorsally and somewhat lighter underneath. The head is uniformly blue, but the back and sides are mottled. When viewed through the water surface they may appear dappled or uniformly light blue. There is light to extensive mottling on the sides, back, and belly, generally in the form of dark spots on a lighter surface, but sometimes the reverse. A chevron, with the vertex behind the blowholes, sometimes marks the transition of coloration between the head and the body. Diatom films on the surface may be seen as an orangish brown or yellow tinge, which gave rise to the alternative name "sulphur-bottom" whale. The head is broad and U-shaped when viewed from above and relatively flat when viewed from the side. Along the centre of the rostrum, there is a single prominent ridge, which ends in an impressive "splash guard" around the blowholes. The flippers are long and pointed, and the dorsal fin is relatively small, variably shaped, and placed about three-quarters of the way back from the snout tip. On the throat, there are 55 to 88 long pleats extending to or near the navel. The mouth contains 270 to 395 pairs of black, broad-based baleen plates, each less than 1 m long. The blow is tall and slender, reaching 9 m or more in height.
Blue whales can be confused with the other large rorquals, fin whale and sei whale. Although the great size of blue whale adults may aid in identification, the best clues for differentiating blue whales from fin or sei whales are colour pattern, head shape, and dorsal-fin shape and position. Blue whales are usually seen alone or in pairs. However, scattered aggregations of a dozen or more may develop on prime feeding grounds. Most adults are 23 to 27 m long (with females growing larger than males). Blue whales feed almost exclusively on krill, though they also take small numbers of copepods.
Threats:-
At present there is no direct threat from whaling but other anthropogenic threats exist. These include noise pollution (masking) from increasing low-frequency noise in the oceans; pollution and ship strikes. Loss of sea ice in the Antarctic due to a warming climate may also impact blue whales by reducing densities of krill, which is its staple food.
Remark:-
Moses, S. (1947), James et al. (1993), Lal Mohan (1992), Somasekharan Nair and Jayaprakash (1987), and Venkatraman and Girijavallabhan (1966) recorded stranding of this species in Kerala. They have been observed off Kerala coast.
Habitat:-
The blue whale is the largest animal ever known and tend to be open-ocean animals, but come close to shore to feed, and possibly to breed, in some areas. ome blue whales are resident others are migratory.
Synonyms:-
Balaena borealis Fischer, 1829; Balaena musculus Linnaeus, 1758; Balaenoptera carolinae Malm, 1866; Balaenoptera gigas Reinhardt, 1857; Balaenoptera indica Blyth, 1859; Balaenoptera jubartes Lacépède, 1804; Balaenoptera miramaris Lahille, 1898; Balaenoptera sibbaldi Van Beneden, 1887; Balaenoptera sibbaldii Flower, 1885; Physalus latirostris Flower, 1865; Physalus sibbaldii Gray, 1847; Pterobalaena gigas Reinhardt, 1857; Pterobalaena grypus Munter, 1877; Rorqualus boops F. Cuvier, 1836; Rorqualus borealis Hamilton, 1837; Rorqualus major Knox, 1870; Sibbaldius antarcticus Burmeister, 1866; Sibbaldius borealis Gray, 1864; Sibbaldius musculus Kellogg, 1929
References:-
Baby, K. (1996). On the stranding of a Blue Whale Balaenoptera musculus at Valappad beach, southwest coast of India. Marine Fisheries Information Service Technical and Extension Series 141: 20.
De Silva, P. (1987). Cetaceans (whales, dolphins and porpoises) recorded off Sri Lanka, India, from the Arabian Sea and Gulf, Gulf of Aden and from the Red Sea.
James, P.S.B.R., Menon, N.G., and Pillai, N.G.K. (1993) On a Blue Whale, Balaenoptera musculus stranded at Chellanam, Cochin. Marine Fisheries Information Service Technical & Extension Series, 122: 23-24.
Jayasankar, P. and Anoop, B. 2010. Identification of Marine Mammals of India. Narendra Publishing House, Delhi.
Jefferson, T.A., Leatherwood, S. and Webber, M.A. 1993. FAO Species identification guide. Marine Mammals of the World: UNEP / FAO, Rome, 320 pp.
Jefferson, T. A., M. A. Webber and R. L. Pitman. (2008). Marine mammals of the world. Academic Press, Amsterdam.
Lal Mohan, R. (1992). Observations on the whales Balaenoptera edeni, B. musculus and Megaptera novaeangliae washed ashore along the Indian coast with a note on their osteology. Journal of the Marine Biological Association of India 34: 253-255.
Moses, S. (1947). Stranding of whales on the coasts of India. Journal of the Bombay Natural History Society 47(2): 377-379.
Reilly, S.B., Bannister, J.L., Best, P.B., Brown, M., Brownell Jr., R.L., Butterworth, D.S., Clapham, P.J., Cooke, J., Donovan, G.P., Urbán, J. & Zerbini, A.N. 2008. Balaenoptera musculus. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 26 September 2014.
Somasekharan Nair, K. and Jayaprakash., A. A. (1987). On a Blue Whale Balaenoptera musculus stranded at Chappa beach, Narakkal, Cochin, southwest coast of India. Marine Fisheries Information Service Technical and Extension Series 71: 17-18.
Sathasivam, K. 2004.Marine Mammals of India. University Press, Hyderabad.
Venkatraman, G. and Girijavallabhan, K. G. (1966). On a whale washed ashore at Calicut. Journal of the Marine Biological Association of India,8: 373-374.
Vivekanandan, E. and Jeyabaskaran, R. 2012. Marine Mammal Species of India. Central Marine Fisheries Research Institute, Kochi, 228pp.