TAXONOMY
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Cetacea
Family: Balaenopteridae
Genus/species: Balaenoptera musculus
GENERAL CHARACTERISTICS: The Blue whale is the largest animal to have ever lived, (almost as big as a Boeing 737. They are actually grayish-blue, with a mottled effect that is visible in some lights and can allow individuals to be identified. 50 people could stand on the tongue, which alone weighs as much as an elephant. The heart of the blue whale is the size of a small car (Volkswagen Beetle).
Blubber can be up to 51 cm (20 inches) thick. The spout of a blue whale can be 9 m (30 ft) high.
Weigh to 203,210 kg or 200 tons (448,000 pounds), as much
as 40 elephants.
Length to nearly 110 feet (33 m (110 ft)
DISTRIBUTION/HABITAT: B. musculus inhabit the open ocean, where they ares found in every ocean except the Arctic, with a range that extends from the periphery of drift-ice in polar seas to the tropics, although it is absent from some seas such as the Mediterranean, Okhotsk and Bering Sea.
They inhabit the open ocean, where it is found most frequently along the continental shelf edge and near polar ice. It feeds at both the surface and to depths of at least 100 m (300 feet).
DIET: Feeds mainly on shrimp-like krill, which are filtered through the baleen plates. Large volumes of water and food can be taken into the mouth because the pleated grooves in the throat expand. As the mouth closes, water is expelled through the baleen plates, which trap the food on the inside to be swallowed. During the summer months, one blue whale can eat more than 4,082 kg (9,000 lbs) of krill every day (up to 40 million krill a day).
REPRODUCTION: Reaches sexual maturity at 7 to 10 years of age, A calf is produced after 10 to 11 months of gestation which is 7 m (23 ft) long and weighs about 27,215 kg (30 tons or 60,000 pounds) and consumes around 190 liters (50 gallons) of the mother’s fat rich-milk resulting in a daily weight gain of about 90 kg (200 pounds).
Weaning occurs at the summer feeding grounds at about seven months old.
B. musculus produces louder calls than any other animal on earth. It appears to have functions in sensing the environment, prey detection and communication with male display.
CONSERVATION: IUCN Red List Endangered (EN).
No Blue whales have been deliberately caught since 1978. Today, there are an estimated 10,000 to 25,000 Blue whales surviving worldwide, which represents around 2 to 11 percent of the total pre-commercial exploitation population.
California Blue whale numbers are rising, and are possibly close to carrying capacity, according to a new study in Marine Mammal Science. The B. musculus whale population is estimated at about 2,200, or 97 percent of the estimated historical level. t’s a conservation success story. (Approximately 3,400 California Blue whales were caught between 1905 and 1971.)
Primary threats
1. vessel strikes
2. fisheries interactions
Additional threats
1. anthropogenic noise
2. habitat degradation
3. pollution
4. vessel disturbance
5. long-term changes in climate
REMARKS: They can dive 150 m (500 ft) below the surface and remain underwater for 30 minutes.
The Blue whale produces louder calls than any other animal on earth. It appears to have functions in sensing the environment, prey detection and communication with male display.
The California Academy’s Blue whale is an 26.5 m (87-ft) long male that weighed about 80 tons with a 6 m (20-ft) long skull. It was captured for its oil off the coast of Vancouver Island in 1908. It gave 60 barrels of oil and 181 kg (400 lbs) of baleen, the latter used for corsets, buggy whips, and other light-weight yet durable products. The Academy acquired the bones in 1915, and they were buried in the Shakespeare Garden in Golden Gate Park until they were ready for mounting, which was completed in 1917 in an open shed.
References
West Coast Blue Whales journals.plos.org/plosone/article?id=10.1371/journal.pone…
California Academy of Sciences www.calacademy.org/explore-science/blue-whale-survival
California Academy of Sciences www.calacademy.org/explore-science/blue-whale-population-…
IUCN Red List (March, 2011) www.iucnredlist.org
NOAA Fisheries Office of Protected Resources – Blue whale www.fisheries.noaa.gov/pr/species/mammals/whales/blue-wha…
ARKive www.arkive.org/blue-whale/balaenoptera-musculus/
Shirihai, H & Jarrett (2006) Whales Dolphins and Other Marine Mammals of the World Princeton University Press.
Evans, P & Weinrich, M (2002) Whales Dolphins and Porpoises D K London New York Munich Melbourne and Delhi.
Reeves, R, R, et al (2002) Guide to Marine Mammals of the World Chanticleer Press, Inc.
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