Changes

==Species Description==

==Species Description==

====Physical characteristics====

====Physical characteristics====

The blue whale, Balaenoptera musculus (Linnaeus 1758), is a cosmopolitan species of baleen whale. Blue whales in the Northern Hemisphere are generally smaller than those in the Southern Ocean. Maximum body length in the North Atlantic was about 88.5 feet (27 m) and the largest blue whale reported from the North Pacific was about 88 feet (26.8 m). Adults in the Antarctic can reach a maximum body length of about 108 feet (33 m) and can weigh more than 330,000 pounds (150,000 kg).

The blue whale, Balaenoptera musculus (Linnaeus 1758), is a cosmopolitan species of baleen whale. Blue whales in the Northern Hemisphere are generally smaller than those in the Southern Ocean. Maximum body length in the North Atlantic was about 88.5 feet (27 m) and the largest blue whale reported from the North Pacific was about 88 feet (26.8 m). Adults in the Antarctic can reach a maximum body length of about 108 feet (33 m) and can weigh more than 330,000 pounds (150,000 kg).

As is true of other baleen whale species, female blue whales are somewhat larger than males. Blue whales are identified by the following characteristics: a long-body and comparatively slender shape; a broad, flat "rostrum" when viewed from above; a proportionately smaller dorsal fin than other baleen whales; and a mottled gray color pattern that appears light blue when seen through the water.

As is true of other baleen whale species, female blue whales are somewhat larger than males. Blue whales are identified by the following characteristics: a long-body and comparatively slender shape; a broad, flat "rostrum" when viewed from above; a proportionately smaller dorsal fin than other baleen whales; and a mottled gray color pattern that appears light blue when seen through the water.

====Life History====

====Life History====

Scientists have yet to discern many details regarding the life history of the blue whale. The best available science suggests the gestation period is approximately 10-12 months and that blue whale calves are nursed for about 6-7 months. Most reproductive activity, including births and mating, takes place during the winter. Weaning probably occurs on, or en route to, summer feeding areas. The average calving interval is probably two to three years. The age of sexual maturity is thought to be 5-15 years. There are no known differences in the reproductive biology of blue whales in the North Pacific and North Atlantic oceans.

Scientists have yet to discern many details regarding the life history of the blue whale. The best available science suggests the gestation period is approximately 10–12 months and that blue whale calves are nursed for about 6–7 months. Most reproductive activity, including births and mating, takes place during the winter. Weaning probably occurs on, or en route to, summer feeding areas. The average calving interval is probably two to three years. The age of sexual maturity is thought to be 5–15 years. There are no known differences in the reproductive biology of blue whales in the North Pacific and North Atlantic oceans.

====Habitat====

====Habitat====

====Ship strikes====

====Ship strikes====

A primary threat to blue whales is mortality and serious injury caused by ship strikes. In the eastern North Pacific, ship strikes were implicated in the deaths of blues whales in 1980, 1986, 1987, 1993 and 2002. The average number of blue whale mortalities in California attributed to ship strikes was 0.2 per year from 1991-1995 and from 1998-2002. In September 2007, three blue whale mortalities were confirmed to be caused by ship strikes in the Santa Barbara Channel off Southern California. These deaths were part of a larger Unusual Mortality Event, declared by the Working Group on Marine Mammal Unusual Mortality Events. In the western North Atlantic, at least nine percent of the whales in the Gulf of St. Lawrence have injuries or scars attributed to contact with ships (Sears et al., 1990). This area has a relatively high risk of ship strikes because the St. Lawrence Seaway has heavy ship traffic during the time of year when blue whales are relatively abundant. In March 1998, a dead 20 m (66ft) male blue whale was brought into Rhode Island waters on the bow of a tanker. The cause of death was determined to be ship strike. There are no records of ship strikes for blue whales in the western North Pacific but mortalities caused by ship strikes have likely occurred without being reported.

A primary threat to blue whales is mortality and serious injury caused by ship strikes. In the eastern North Pacific, ship strikes were implicated in the deaths of blues whales in 1980, 1986, 1987, 1993 and 2002. The average number of blue whale mortalities in California attributed to ship strikes was 0.2 per year from 1991–1995 and from 1998-2002. In September 2007, three blue whale mortalities were confirmed to be caused by ship strikes in the Santa Barbara Channel off Southern California. These deaths were part of a larger Unusual Mortality Event, declared by the Working Group on Marine Mammal Unusual Mortality Events. In the western North Atlantic, at least nine percent of the whales in the Gulf of St. Lawrence have injuries or scars attributed to contact with ships (Sears et al., 1990). This area has a relatively high risk of ship strikes because the St. Lawrence Seaway has heavy ship traffic during the time of year when blue whales are relatively abundant. In March 1998, a dead 20 m (66 ft) male blue whale was brought into Rhode Island waters on the bow of a tanker. The cause of death was determined to be ship strike. There are no records of ship strikes for blue whales in the western North Pacific but mortalities caused by ship strikes have likely occurred without being reported.

====Fisheries interactions====

====Fisheries interactions====

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*Gunnlaugsson, T., and J. Sigurjónsson. 1990. NASS-87: "Estimation of whale abundance based on observations made on board Icelandic and Faroese survey vessels." Report to the International Whaling Commission. 40:571-580.  

*IWC. 2007. International Whaling Commission statistics. [[www.iwcoffice.org]]  

*IWC. 2007. International Whaling Commission statistics. [[www.iwcoffice.org]]  

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*Ohsumi, S., and S. Wada. 1972. "Stock assessment of blue whales in the North Pacific." Unpublished working paper for the 24th meeting of the Scientific Committee of the International Whaling Commission, 20 pp.  

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*O'Shea, T.J., and R.L. Brownell, Jr. 1994. "Organochlorine and metal contaminants in baleen whales: a review and evaluation of conservation implications." Sci. Total Environment 154:179-200.  

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*Sears, R. 1990. "The Cortez blues." ''Whalewatcher'' 24(2):12-15.  

*Sears, R., F.W. Wenzel, and J.M. Williamson. 1987. ''The Blue Whale: A Catalogue of Individuals from the Western North Atlantic (Gulf of St. Lawrence)''. Mingan Island Cetacean Study, St. Lambert, Quebec. 27 pp.  

*Sears, R., F.W. Wenzel, and J.M. Williamson. 1987. ''The Blue Whale: A Catalogue of Individuals from the Western North Atlantic (Gulf of St. Lawrence)''. Mingan Island Cetacean Study, St. Lambert, Quebec. 27 pp.  

*Watkins, W.A., J.E. George, M.A. Daher, K. Mullin, D.L. Martin, S.H. Haga, and N.A. DiMarzio. 2000. "Whale call data for the North Pacific November 1995 through July 1999: Occurrence of calling whales and source locations from SOSUS and other acoustic systems". Technical Report WHOI_00_02 available from Woods Hole Oceanographic Institution. 160pp.  

*Watkins, W.A., J.E. George, M.A. Daher, K. Mullin, D.L. Martin, S.H. Haga, and N.A. DiMarzio. 2000. "Whale call data for the North Pacific November 1995 through July 1999: Occurrence of calling whales and source locations from SOSUS and other acoustic systems". Technical Report WHOI_00_02 available from Woods Hole Oceanographic Institution. 160pp.  

*Yablokov, A.V. 1994. Validity of whaling data. Nature 367:108.  

*Yablokov, A.V. 1994. Validity of whaling data. Nature 367:108.  

*Yochem, P.K., and S. Leatherwood. 1985. Blue whale ''Balaenoptera musculus'' (Linnaeus, 1758). Pp. 193-240 In: Ridgway, S.H. and R. Harrison (eds.), ''Handbook of Marine Mammals'', Vol. 3: "The Sirenians and Baleen Whales." Academic Press, London. 362 pp.  

*Yochem, P.K., and S. Leatherwood. 1985. Blue whale ''Balaenoptera musculus'' (Linnaeus, 1758). pp. 193–240 In: Ridgway, S.H. and R. Harrison (eds.), ''Handbook of Marine Mammals'', Vol. 3: "The Sirenians and Baleen Whales." Academic Press, London. 362 pp.  

*Zemsky, V.A., A.A. Berzin, Y.A. Mikhaliev, and D.D. Tormosov. 1995a. "Soviet Antarctic pelagic whaling after WWII: review of actual catch data. Report of the Sub-committee on Southern hemisphere baleen whales". Rep. int. Whal. Commn. 45:131-135.  

*Zemsky, V.A., A.A. Berzin, Y.A. Mikhaliev, and D.D. Tormosov. 1995a. "Soviet Antarctic pelagic whaling after WWII: review of actual catch data. Report of the Sub-committee on Southern hemisphere baleen whales". Rep. int. Whal. Commn. 45:131-135.  

*Zemsky, V.A., A.A. Berzin, Y.A. Mikhaliev, and D.D. Tormosov. 1995b. Antarctic whaling data (1947-1972). Center for Russian Environmental Policy, Moscow. 320 pp. [In Russian with English summaries.]  

*Zemsky, V.A., A.A. Berzin, Y.A. Mikhaliev, and D.D. Tormosov. 1995b. Antarctic whaling data (1947–1972). Center for Russian Environmental Policy, Moscow. 320 pp. [In Russian with English summaries.]