{{Otheruses}}{{pp-semi-protected|small=yes}}{{Otheruses}}{{pp-semi-protected|small=yes}}
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{{Taxobox
| name =
Blue Whale
| status = EN
| status_system = iucn3.1
| status_ref =
| image = Bluewhale877.jpg
| image_width = 300px
| image_caption = Adult Blue Whale from the eastern Pacific Ocean
| image2 = Blue_whale_size.svg
| image2_width = 300px
| image2_caption = Size comparison against an average human
| regnum =
AnimalAnimals are a major group of mostly multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously...
ia
| phylum = Chordata
| classis =
MammalMammals are a class of vertebrate animals whose females are characterized by the possession of mammary glands while both males and females are characterized by sweat glands, hair, three middle ear bones used in hearing, and a neocortex region in the brain.Mammals are divided into three main...
ia
| ordo =
CetaceaThe order Cetacea includes whales, dolphins, and porpoises. Cetus is Latin and is used in biological names to mean "whale"; its original meaning, "large sea animal", was more general. It comes from Ancient Greek , meaning "whale" or "any huge fish or sea monster"...
| subordo = Mysticeti
| familia = Balaenopteridae
| genus =
BalaenopteraBalaenoptera is a genus of Balaenopteridae, the Rorqual whales, and contains eight species. The species Balaenoptera omurai was published in 2003...
| species =
B. musculus
| binomial =
Balaenoptera musculus
| binomial_authority = (Linnaeus, 1758)
| subdivision_ranks =
SubspeciesSubspecies in biological classification, is 1) a taxonomic rank subordinate to species, or 2) a taxonomic unit, a taxon in that rank...
| subdivision =
- B. m. brevicauda
The Pygmy Blue Whale is a subspecies of the Blue Whale found in the Indian Ocean and the southern Pacific Ocean....
Ichihara, 1966
- ?B. m. indica Blyth, 1859
- B. m. intermedia Burmeister, 1871
- B. m. musculus Linnaeus, 1758
| range_map = cetacea_range_map_Blue_Whale.PNG
| range_map_caption = Blue Whale range
}}
The
Blue Whale (
Balaenoptera musculus) is a
marine mammalMarine mammals are a diverse group of roughly 120 species of mammal that are primarily ocean-dwelling or depend on the ocean for food. They include the cetaceans , the sirenians , the pinnipeds , and several otters...
belonging to the suborder of
baleen whaleThe baleen whales, also called whalebone whales or great whales, form the Mysticeti, one of two suborders of the Cetacea . Baleen whales are characterized by having baleen plates for filtering food from water, rather than having teeth. This distinguishes them from the other suborder of cetaceans,...
s (called Mysticeti). At up to {{convert|32.9|m|ft}} in length and {{convert|172|metric ton|short ton}} or more in weight, it is the largest animal ever known to have existed.
Long and slender, the Blue Whale's body can be various shades of bluish-grey dorsally and somewhat lighter underneath. There are at least three distinct
subspeciesSubspecies in biological classification, is 1) a taxonomic rank subordinate to species, or 2) a taxonomic unit, a taxon in that rank...
:
B. m. musculus of the North Atlantic and North Pacific,
B. m. intermedia of the
Southern OceanThe Southern Ocean, also known as the Great Southern Ocean, the Antarctic Ocean and the South Polar Ocean, comprises the southernmost waters of the World Ocean south of 60° S latitude. The International Hydrographic Organization has designated the Southern Ocean as an oceanic division encircling...
and
B. m. brevicauda (also known as the
Pygmy Blue WhaleThe Pygmy Blue Whale is a subspecies of the Blue Whale found in the Indian Ocean and the southern Pacific Ocean....
) found in the
Indian OceanThe Indian Ocean is the third largest of the world's oceanic divisions, covering about 20% of the water on the Earth's surface. It is bounded on the north by South Asia ; on the west by Africa; on the east by Indochina, the Sunda Islands, and Australia; and on the south by the Southern Ocean...
and South Pacific Ocean.
B. m. indica, found in the Indian Ocean, may be another subspecies. As with other baleen whales, its diet consists almost exclusively of small
crustaceanCrustaceans are a very large group of arthropods, comprising almost 52,000 described species , and are usually treated as a subphylum . They include various familiar animals, such as crabs, lobsters, crayfish, shrimp, krill and barnacles...
s known as
krillKrill is a type of shrimp-like marine invertebrate animal. These small crustaceans are important organisms of the zooplankton, particularly as food for baleen whales, manta rays, whale sharks, crabeater seals, and other seals, and a few seabird species that feed almost exclusively on them. Another...
.
Blue Whales were abundant in nearly all the oceans until the beginning of the twentieth century. For over 40 years, they were hunted almost to
extinctionIn biology and ecology, extinction is the end of an organism or group of taxa. The moment of extinction is generally considered to be the death of the last individual of that species...
by
whalersWhaling is the hunting of whales which dates back to at least 3,000 BC. The evolution of traditional Arctic whaling developed with increasing rapidity by early organized fleets in the 17th century; competitive national whaling industries in the 18th and 19th centuries; and the introduction of...
until protected by the international community in 1966. A 2002 report estimated there were 5,000 to 12,000 Blue Whales worldwide, located in at least five groups. More recent research into the Pygmy subspecies suggests this may be an underestimate. Before whaling, the largest population was in the Antarctic, numbering approximately 239,000 (range 202,000 to 311,000). There remain only much smaller (around 2,000) concentrations in each of the North-East
PacificThe Pacific Ocean is the largest of the Earth's oceanic divisions. Its name is derived from the Latin name Tepre Pacificum, "peaceful sea", bestowed upon it by the Portuguese explorer Ferdinand Magellan. It extends from the Arctic in the north to Antarctica in the south, bounded by Asia and...
,
Antarctic| style="border-top:solid 1px #ccd2d9; padding:0.4em 1em 0.4em 0; vertical-align:top;" | 14,000,000 km
2 280,000 km
2 13,720,000 km
2 |-! style="border-top: solid 1px #ccd2d9; padding: 0.4em 1em 0.4em 0; vertical-align: top;...
, and
Indian OceanThe Indian Ocean is the third largest of the world's oceanic divisions, covering about 20% of the water on the Earth's surface. It is bounded on the north by South Asia ; on the west by Africa; on the east by Indochina, the Sunda Islands, and Australia; and on the south by the Southern Ocean...
groups. There are two more groups in the North
AtlanticThe Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about 106.4 million square kilometres , it covers approximately one-fifth of the Earth's surface and about one-quarter of its water surface area. The first part of its name refers to the Atlas of Greek...
, and at least two in the
Southern HemisphereThe Southern Hemisphere is the half of a planet that is south of the equator—the word hemisphere literally means 'half ball'...
.
Taxonomy
{{seealso|Evolution of cetaceans}}
Blue Whales are rorquals (family Balaenopteridae), a family that includes the
Humpback WhaleThe humpback whale is a baleen whale. One of the larger rorqual species, adults range in length from and weigh approximately . The humpback has a distinctive body shape, with unusually long pectoral fins and a knobbly head. It is an acrobatic animal, often breaching and slapping the water...
, the
Fin WhaleThe Fin Whale , also called the Finback Whale, Razorback, or Common Rorqual, is a marine mammal belonging to the suborder of baleen whales...
,
Bryde's WhaleBryde’s Whales are the least-known and in many ways the most unusual of the rorquals. They are small by rorqual standards—no more than about 25 tonnes—prefer tropical and temperate waters to the polar seas that other whales in their family frequent; are largely coastal rather than...
, the
Sei WhaleThe Sei Whale , Balaenoptera borealis, is a baleen whale, the third-largest rorqual after the Blue Whale and the Fin Whale. It can be found worldwide in all oceans and adjoining seas, and prefers deep off-shore waters. It tends to avoid polar and tropical waters and semi-enclosed bodies of water...
and the
Minke WhaleMinke Whale or Lesser Rorqual is a name given to two species of marine mammal belonging to a clade within the suborder of baleen whales...
. The family Balaenopteridae is believed to have diverged from the other families of the suborder Mysticeti as long ago as the middle
OligoceneThe Oligocene is a geologic epoch of the Paleogene period and extends from about 33.9 million to 23 million years before the present. As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...
. However, it is not known when the members of those families diverged from each other.
The Blue Whale is usually classified as one of eight species in the genus
Balaenoptera; one authority places it in a separate monotypic genus,
Sibbaldus, but this is not accepted elsewhere.
DNADeoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms and some viruses. The main role of DNA molecules is the long-term storage of information...
sequencing analysis indicates that the Blue Whale is
phylogeneticallyIn biology, phylogenetics is the study of evolutionary relatedness among various groups of organisms , which is discovered through molecular sequencing data and morphological data matrices...
closer to the
Sei WhaleThe Sei Whale , Balaenoptera borealis, is a baleen whale, the third-largest rorqual after the Blue Whale and the Fin Whale. It can be found worldwide in all oceans and adjoining seas, and prefers deep off-shore waters. It tends to avoid polar and tropical waters and semi-enclosed bodies of water...
(
Balaenoptera borealis) and
Bryde's WhaleBryde’s Whales are the least-known and in many ways the most unusual of the rorquals. They are small by rorqual standards—no more than about 25 tonnes—prefer tropical and temperate waters to the polar seas that other whales in their family frequent; are largely coastal rather than...
(
Balaenoptera brydei) than to other
Balaenoptera species, and closer to the
Humpback WhaleThe humpback whale is a baleen whale. One of the larger rorqual species, adults range in length from and weigh approximately . The humpback has a distinctive body shape, with unusually long pectoral fins and a knobbly head. It is an acrobatic animal, often breaching and slapping the water...
(
Megaptera) and the
Gray WhaleThe Gray Whale is a baleen whale that travels between feeding and breeding grounds yearly. It reaches a length of about 16 meters , a weight of 36 tons and an age of 50–60 years. Gray Whales were once called Devil Fish because of their fighting behavior when hunted...
(
Eschrichtius) than to the
minke whaleMinke Whale or Lesser Rorqual is a name given to two species of marine mammal belonging to a clade within the suborder of baleen whales...
s (
Balaenoptera acutorostrata and
Balaenoptera bonaerensis). If further research confirms these relationships, it will be necessary to reclassify the rorquals.
There have been at least 11 documented cases of Blue/
FinThe Fin Whale , also called the Finback Whale, Razorback, or Common Rorqual, is a marine mammal belonging to the suborder of baleen whales...
hybrid adults in the wild. Arnason and Gullberg describe the genetic distance between a Blue and a Fin as about the same as that between a human and a gorilla. Researchers working off of Fiji believe they photographed a hybrid
HumpbackThe humpback whale is a baleen whale. One of the larger rorqual species, adults range in length from and weigh approximately . The humpback has a distinctive body shape, with unusually long pectoral fins and a knobbly head. It is an acrobatic animal, often breaching and slapping the water...
/Blue Whale.
The specific name
musculus is
LatinLatin is an Italic language originally spoken in Latium and Ancient Rome. Through the Roman conquest, Latin spread throughout the Mediterranean and a large part of Europe...
and could mean "muscular", but it can also be interpreted as "little mouse".
LinnaeusCarl Linnaeus was a Swedish botanist, physician, and zoologist, who laid the foundations for the modern scheme of binomial nomenclature...
, who named the species in his seminal
Systema NaturaeThe book Systema Naturae was one of the major works of the Swedish botanist, zoologist and physician Carolus Linnaeus. Its full title is Systema naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis or translated: "System of...
of 1758, would have known this and may have intended the ironic
double meaningA double entendre or adianoeta is a figure of speech in which a spoken phrase is devised to be understood in either of two ways. Often the first meaning is straightforward, while the second meaning is less so; often risqué, inappropriate, or ironic....
.
Herman MelvilleHerman Melville was an American novelist, short story writer, essayist and poet who is often classified as part of dark romanticism...
called this species
Sulphur-bottom in his novel
Moby-DickThe cetology of Moby-Dick is the zoological classification and study of the properties of whales introduced by U.S. author Herman Melville in his 1851 novel Moby-Dick. Although the novel is a work of fiction, Melville included sequences of chapters concerned largely with an objective discussion of...
due to an orange-brown or yellow tinge on the underparts from
diatomDiatoms are a major group of eukaryotic algae, and are one of the most common types of phytoplankton. Most diatoms are unicellular, although they can exist as colonies in the shape of filaments or ribbons Diatoms (Greek: (dia) = "through" + (temnein) = "to cut", i.e., "cut in half") are a major...
films on the skin. Other common names for the Blue Whale have included the
Sibbald's Rorqual (after
Sir Robert SibbaldSir Robert Sibbald , Scottish physician and antiquary, was born in Edinburgh. He was the son of David Sibbald and Margaret Boyd ....
), the
Great Blue Whale and the
Great Northern Rorqual. These names have now fallen into disuse.
Authorities classify the species into three or four subspecies:
B. m. musculus, the Northern Blue Whale consisting of the North Atlantic and North Pacific populations,
B. m. intermedia, the Southern Blue Whale of the
Southern OceanThe Southern Ocean, also known as the Great Southern Ocean, the Antarctic Ocean and the South Polar Ocean, comprises the southernmost waters of the World Ocean south of 60° S latitude. The International Hydrographic Organization has designated the Southern Ocean as an oceanic division encircling...
,
B. m. brevicauda, the
Pygmy Blue WhaleThe Pygmy Blue Whale is a subspecies of the Blue Whale found in the Indian Ocean and the southern Pacific Ocean....
found in the Indian Ocean and South Pacific, and the more problematic
B. m. indica, the Great Indian Rorqual, which is also found in the Indian Ocean and, although described earlier, may be the same subspecies as
B. m. brevicauda.
Description and behaviour
The Blue Whale has a long tapering body that appears stretched in comparison with the stockier build of other whales. The head is flat and
U-shaped and has a prominent ridge running from the
blowholethumb|250px|right|The single blowhole of a [[bottlenose dolphin]] just before going under againIn biology, a blowhole is the hole at the top of a Cetacean's head through which the animal breathes air. It is homologous with the nostril of other mammals. As whales reach the water surface to breathe,...
to the top of the upper lip. The front part of the mouth is thick with
baleenBaleen or whalebone enables baleen whales to feed. These whales do not have teeth, but instead have rows of baleen plates in the upper jaw – flat, flexible plates with frayed edges, arranged in two parallel rows, looking like combs of thick hair. Baleen is not bone, but is composed of...
plates; around 300 plates (each around one metre (3.2 ft) long) hang from the upper jaw, running 0.5 m (1.6 ft) back into the mouth. Between 60 and 90 grooves (called ventral pleats) run along the throat parallel to the body. These pleats assist with evacuating water from the mouth after lunge feeding (see feeding below).
The
dorsal finA dorsal fin is a fin located on the backs of some fish, whales, dolphins, and porpoises, as well as the ichthyosaurs. Depending on the species, an animal can have up to three of them. Its main purpose is to stabilize the animal against rolling and assist in sudden turns...
is small, visible only briefly during the dive sequence. Located around three-quarters of the way along the length of the body, it varies in shape from one individual to another; some only have a barely perceptible lump, but others may have prominent and falcate dorsals. When surfacing to breathe, the Blue Whale raises its shoulder and blowhole out of the water to a greater extent than other large whales such as the
FinThe Fin Whale , also called the Finback Whale, Razorback, or Common Rorqual, is a marine mammal belonging to the suborder of baleen whales...
or
SeiThe Sei Whale , Balaenoptera borealis, is a baleen whale, the third-largest rorqual after the Blue Whale and the Fin Whale. It can be found worldwide in all oceans and adjoining seas, and prefers deep off-shore waters. It tends to avoid polar and tropical waters and semi-enclosed bodies of water...
. Observers can use this trait to differentiate between species at sea. Some Blue Whales in the North Atlantic and North Pacific raise their tail fluke when diving. When breathing, the whale emits a spectacular vertical single-column spout up to {{convert|12|m|ft}}, typically {{convert|9|m|ft}}. Its
lungThe lung or pulmonary system is the essential respiration organ in air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located in the chest on either side of the heart...
capacity is 5,000 litres (1320 U.S. gallons). Blue whales have twin blowholes shielded by a large splashguard.
The flippers are {{convert|3|-|4|m|ft}} long. The upper sides are grey with a thin white border. The lower sides are white. The head and tail fluke are generally uniformly grey. The whale's upper parts, and sometimes the flippers, are usually mottled. The degree of mottling varies substantially from individual to individual. Some may have a uniform slate-grey color, but others demonstrate a considerable variation of dark blues, greys and blacks, all tightly mottled.
Blue Whales can reach speeds of {{convert|50|km/h|mph}} over short bursts, usually when interacting with other whales, but {{convert|20|km/h|mph}} is a more typical traveling speed. When feeding, they slow down to {{convert|5|km/h|mph}}.
Blue Whales most commonly live alone or with one other individual. It is not known how long traveling pairs stay together. In locations where there is a high concentration of food, as many as 50 Blue Whales have been seen scattered over a small area. However, they do not form the large close-knit groups seen in other baleen species.
Size
Blue Whales are difficult to weigh because of their size. Most Blue Whales killed by whalers were not weighed whole, but cut up into manageable pieces first. This caused an underestimate of the total weight of the whale, due to the loss of blood and other fluids. Nevertheless, measurements between {{convert|150|-|170|metric ton |short ton}} were recorded of animals up to {{convert|27|m|ft}} in length. The weight of a {{convert|30|m|ft}} individual is believed by the American
National Marine Mammal LaboratoryThe National Marine Mammal Laboratory is a United States research laboratory that undertakes research into marine mammals under the direction of the National Marine Fisheries Service and the National Oceanic and Atmospheric Administration....
(NMML) to be in excess of {{convert|180|metric ton|short ton}}. The largest Blue Whale accurately weighed by NMML scientists to date was a female that weighed {{convert|177|metric ton|short ton}}.
The Blue Whale is the largest animal ever to have lived. The largest known
dinosaur{{Otheruses}}{{pp-semi-protected|small=yes}}{{Otheruses}}{{pp-semi-protected|small=yes}}{{Taxobox|name = Dinosaurs|fossil_range = {{Fossil range|230|65|earliest=230|latest=0|PS=
Descendant taxon Aves survives to present.}}|image = field_dinos_2.jpg...
of the
MesozoicThe Mesozoic Era is one of three geologic eras of the Phanerozoic eon. The division of time into eras dates back to Giovanni Arduino, in the 18th century, although his original name for the era now called the "Mesozoic" was "Secondary" The Mesozoic Era is one of three geologic eras of the...
Era was the
ArgentinosaurusArgentinosaurus is a genus of sauropod dinosaur first discovered by Guillermo Heredia in Argentina. The generic name means "silver lizard", in reference to the country in which it was discovered...
, which is estimated to have weighed up to {{convert|90|metric ton|short ton}}, though a controversial vertebra of
AmphicoeliasAmphicoelias is a genus of herbivorous sauropod dinosaur that includes what may be the largest dinosaur ever discovered, A. fragillimus. Based on surviving descriptions of a single fossil bone, A...
fragillimus may indicate an animal of up to {{convert|122|metric ton|short ton}} and {{convert|40|-|60|m|ft}}. Furthermore, there are weight estimates for the very poorly known
BruhathkayosaurusBruhathkayosaurus might have been the largest dinosaur that ever lived. The accuracy of this claim, however, has been mired in controversy and debate...
ranging from {{convert|140|-|220|metric ton|short ton}}, besides length estimates up to about {{convert|45|m|ft}}. The extinct fish
LeedsichthysLeedsichthys was a giant pachycormid that lived in the oceans of the Middle Jurassic period. The closest living relative of the pachycormids is the bowfin, Amia calva, but this is only very distantly related...
may have approached its size. However, complete fossils are difficult to come by, making size comparisons difficult. All these animals are considered to be smaller than the blue whale.
There is some uncertainty about the biggest Blue Whale ever found, as most data comes from Blue Whales killed in
Antarctic| style="border-top:solid 1px #ccd2d9; padding:0.4em 1em 0.4em 0; vertical-align:top;" | 14,000,000 km
2 280,000 km
2 13,720,000 km
2 |-! style="border-top: solid 1px #ccd2d9; padding: 0.4em 1em 0.4em 0; vertical-align: top;...
waters during the first half of the twentieth century and was collected by whalers not well-versed in standard zoological measurement techniques. The longest whales ever recorded were two females measuring {{convert|33.6|-|33.3|m|ft}}respectively. The longest whale measured by
scientistA scientist, in the broadest sense, is any person who engages in a systematic activity to acquire knowledge or an individual that engages in such practices and traditions that are linked to schools of thought or philosophy. In a more restricted sense, a scientist is an individual who uses the...
s at the NMML was {{convert|29.9|m|ft}}.
A Blue Whale's
tongueThe tongue is a muscle on the floor of the mouth that manipulates food for chewing and swallowing . It is the primary organ of taste, as much of the upper surface of the tongue is covered in papillae and taste buds. A secondary function of the tongue is speech, in which the organ assists...
weighs around {{convert|2.7|metric ton|short ton}} and, when fully expanded, its mouth is large enough to hold up to {{convert|90|metric ton|short ton}} of food and water. Despite the size of its mouth, the dimensions of its throat are such that a Blue Whale cannot swallow an object wider than a beach ball. Its
heartThe heart is a muscular organ found in all vertebrates that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...
weighs {{convert|600|kg|lb}} and is the
largestThe largest body part is either the largest given body part across all animals or the largest example of a body part within a species. The largest animals on the planet are not the only ones to have large body parts, with some smaller animals actually having one particularly enlarged area of the...
known in any animal. A Blue Whale's
aortaThe aorta is the largest artery in the body, originating from the left ventricle of the heart and bringing oxygenated blood to all parts of the body in the systemic circulation....
is about {{convert|23|cm|in}} in diameter. During the first seven months of its life, a Blue Whale calf drinks approximately 400 litres (100 U.S. gallons) of milk every day. Blue Whale calves gain
weightAlthough some people prefer the less-ambiguous term body mass, the term body weight is overwhelmingly used in daily English speech and in biological and medical science contexts to describe the mass of an organism's body. Body weight is measured in kilograms throughout the world, although in some...
quickly, as much as {{convert|90|kg|lb}} every 24 hours. Even at birth, they weigh up to {{convert|2700|kg|lb}}—the same as a fully grown
hippopotamusThe hippopotamus or hippo is a large, mostly plant-eating mammal in sub-Saharan Africa, and one of only two extant species in the family Hippopotamidae...
.
Feeding
Blue Whales feed almost exclusively on
krillKrill is a type of shrimp-like marine invertebrate animal. These small crustaceans are important organisms of the zooplankton, particularly as food for baleen whales, manta rays, whale sharks, crabeater seals, and other seals, and a few seabird species that feed almost exclusively on them. Another...
, though they also take small numbers of copepods. The species of this
zooplanktonZooplankton are the heterotrophic type of plankton. Plankton are organisms drifting in the water column of oceans, seas, and bodies of fresh water. The name of zooplankton is derived from the Greek zoon , meaning "animal", and , meaning "wanderer" or "drifter"...
eaten by Blue Whales varies from ocean to ocean. In the North Atlantic,
Meganyctiphanes norvegica,
Thysanoessa raschiiThysanoessa raschii, sometimes known as Arctic krill, is one of the most common euphausiid species of the subarctic and Arctic seas. They may reach 20–25 mm long, and are sexually mature above 14 mm ....
,
Thysanoessa inermis and
Thysanoessa longicaudata are the usual food; in the North Pacific,
Euphausia pacifica,
Thysanoessa inermis,
Thysanoessa longipes,
Thysanoessa spinifera,
Nyctiphanes symplex and
Nematoscelis megalops; and in the Antarctic,
Euphausia superba,
Euphausia crystallorophias and
Euphausia valentin.
An adult Blue Whale can eat up to 40 million krill in a day. The whales always feed in the areas with the highest concentration of krill, sometimes eating up to {{convert|3600|kg|lb}} of krill in a single day. This daily calorie requirement of an adult Blue Whale is in the region of 1.5 million. This means that they typically feed at depths of more than {{convert|100|m|ft}} during the day and only surface-feed at night. Dive times are typically 10 minutes when feeding, though dives of up to 20 minutes are common. The longest recorded dive is 36 minutes. The whale feeds by lunging forward at groups of krill, taking the animals and a large quantity of water into its mouth. The water is then squeezed out through the baleen plates by pressure from the ventral pouch and tongue. Once the mouth is clear of water, the remaining krill, unable to pass through the plates, are swallowed. The Blue Whale also incidentally consumes small fish, crustaceans and squid caught up with krill.
Life history
Mating starts in late autumn and continues to the end of winter. Little is known about mating behaviour or breeding grounds. Females typically give birth once every two to three years at the start of the winter after a
gestation periodFor mammals the gestation period is the time in which a fetus develops, beginning with fertilization and ending at the embryo stage. The duration of this period varies between species.-Duration:...
of ten to twelve months. The calf weighs about {{convert|2.5|metric ton|short ton}} and is around {{convert|7|m|ft}} in length. Blue Whale calves drink 380–570 litres (100–150 U.S. gallons) of milk a day.
WeaningWeaning is the process of gradually introducing a mammal infant, either human or animal, to what will be its adult diet and withdrawing the supply of its mother's milk.The process takes place only in mammals, as only mammals produce milk...
takes place for about six months, by which time the calf has doubled in length. Sexual maturity is typically reached at eight to ten years, by which time males are at least {{convert|20|m|ft}} long (or more in the Southern Hemisphere). Females are larger still, reaching sexual maturity at around the age of five, by which they are about {{convert|21|m|ft}} long.
Scientists estimate that Blue Whales can live for at least 80 years; however, since individual records do not date back into the whaling era, this will not be known with certainty for many years. The longest recorded study of a single individual is 34 years, in the north-east Pacific. The whales' only natural predator is the
OrcaThe Killer Whale or Orca , or less commonly, Blackfish, is the largest species of the dolphin family. Most people think that they are whales, but they are actually dolphins. They are called killer whales often because they sometimes hunt whales for food...
. Studies report that as many as 25% of mature Blue Whales have scars resulting from Orca attacks. The mortality rate of such attacks is unknown.
Blue Whale strandings are extremely uncommon, and, because of the species' social structure, mass strandings are unheard of. However, when strandings do occur, they can become the focus of public interest. In 1920, a Blue Whale washed up near
BragarBragar is a crofting township or village on the West Side of the Isle of Lewis in Scotland, neighboured by Shawbost to the south and Arnol to the north. Bragar features a distinctive whale-bone arch as well as a school, post office, war memorial and a shore...
on the Isle of Lewis in the
Outer HebridesThe Outer Hebrides, comprise an island chain off the west coast of Scotland...
of
ScotlandScotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...
. It had been shot in the head by whalers, but the harpoon had failed to explode. As with other mammals, the fundamental instinct of the whale was to try to carry on breathing at all costs, even though this meant beaching to prevent itself from drowning. Two of the whale's bones were erected just off a main road on Lewis and remain a tourist attraction.
Vocalizations
{{seealso|Whale song}}
Multimedia relating to the Blue Whale
|
|
> filename = Blue whale atlantic1.ogg
| title = A Blue Whale song
| description = Recorded in the Atlantic (1)
| format = OggOgg is a free, open standard container format maintained by the Xiph.Org Foundation. The creators of the Ogg format claim that it is unrestricted by software patents and is designed to provide for efficient streaming and manipulation of high quality digital multimedia.The name ‘Ogg’ refers to the...
| filename2 = Blue whale atlantic2.ogg
| title2 = A Blue Whale song
| description2 = Recorded in the Atlantic (2)
| format2 = OggOgg is a free, open standard container format maintained by the Xiph.Org Foundation. The creators of the Ogg format claim that it is unrestricted by software patents and is designed to provide for efficient streaming and manipulation of high quality digital multimedia.The name ‘Ogg’ refers to the...
| filename3 = Blue whale atlantic3.ogg
| title3 = A Blue Whale song
| description3 = Recorded in the Atlantic (3)
| format3 = OggOgg is a free, open standard container format maintained by the Xiph.Org Foundation. The creators of the Ogg format claim that it is unrestricted by software patents and is designed to provide for efficient streaming and manipulation of high quality digital multimedia.The name ‘Ogg’ refers to the...
| filename4 = Blue_Whale_NE_Pacific.ogg
| title4 = A Blue Whale song
| description4 = Recorded in North Eastern Pacific
| format4 = OggOgg is a free, open standard container format maintained by the Xiph.Org Foundation. The creators of the Ogg format claim that it is unrestricted by software patents and is designed to provide for efficient streaming and manipulation of high quality digital multimedia.The name ‘Ogg’ refers to the...
| filename5 = Blue_Whale_South_Pacific.ogg
| title5 = A Blue Whale song
| description5 = Recorded in the South Pacific
| format5 = OggOgg is a free, open standard container format maintained by the Xiph.Org Foundation. The creators of the Ogg format claim that it is unrestricted by software patents and is designed to provide for efficient streaming and manipulation of high quality digital multimedia.The name ‘Ogg’ refers to the...
| filename6 = Blue_Whale_West_Pacific.ogg
| title6 = A Blue Whale song
| description6 = Recorded in the West Pacific
| format6 = OggOgg is a free, open standard container format maintained by the Xiph.Org Foundation. The creators of the Ogg format claim that it is unrestricted by software patents and is designed to provide for efficient streaming and manipulation of high quality digital multimedia.The name ‘Ogg’ refers to the...
}}
Estimates made by Cummings and Thompson (1971) suggest that source level of sounds made by Blue Whales are between 155 and 188
decibelThe decibel is a logarithmic unit of measurement that expresses the magnitude of a physical quantity relative to a specified or implied reference level. Since it expresses a ratio of two quantities with the same unit, it is a dimensionless unit...
s when measured relative to a reference pressure of one micropascal at one metre. All Blue Whale groups make calls at a
fundamental frequencyThe fundamental tone, often referred to simply as the fundamental and abbreviated f
0 or F
0, is the lowest frequency in a harmonic series....
of between 10 and 40
HzThe hertz is a unit of frequency. It is defined as the number of complete cycles per second. It is the basic unit of frequency in the International System of Units , and is used worldwide in both general-purpose and scientific contexts...
, and the lowest frequency sound a human can typically perceive is 20 Hz. Blue Whale calls last between ten and thirty seconds. Blue Whales off the coast of
Sri LankaSri Lanka , officially the Democratic Socialist Republic of Sri Lanka , is an island country in South Asia, located about off the southern coast of India...
have been repeatedly recorded making "songs" of four notes duration lasting about two minutes each, reminiscent of the well-known
Humpback Whale songsWhale song is the sound made by whales to communicate.The word "song" is used to describe the pattern of regular and predictable sounds made by some species of whales, notably the Humpback Whale...
. Researchers believe that as this phenomenon has not been seen in any other populations, it may be unique to the
B. m. brevicauda (Pygmy) subspecies.
The reason for vocalization is unknown. Richardson
et al. (1995) discuss six possible reasons:
- Maintenance of inter-individual distance
- Species and individual recognition
- Contextual information transmission (e.g., feeding, alarm, courtship)
- Maintenance of social organization (e.g., contact calls between females and males)
- Location of topographic features
- Location of prey resources
Hunting era
{{main|History of whaling}}
Blue Whales are not easy to catch or kill. Their speed and power meant that they were rarely pursued by early whalers, who instead targeted
SpermThe sperm whale, , is a species of marine mammal in the order cetacea, a toothed whale with the largest brain of any animal. The whale was named after the milky-white waxy substance, spermaceti, found in its head and originally mistaken for sperm...
and
Right WhaleRight whales are the species of large baleen whales belonging to the genus Eubalaena. Three right whale species are recognized in this genus. They are closely related genetically to the larger, arctic Bowhead Whale, which is currently placed in its own genus, Balaena...
s. In 1864, the Norwegian
Svend FoynSvend Foyn was a Norwegian whaling captain who pioneered revolutionary methods for hunting and processing whales. Svend Foyn introduced the modern harpoon gun and brought whaling into a modern age.-Background:...
equipped a
steamboatA steamboat or steamship, sometimes called a steamer, is a ship in which the primary method of propulsion is steam power, typically driving propellers or paddlewheels....
with
harpoonA harpoon is a long spear-like instrument used in fishing to catch fish or large marine mammals such as whales. It accomplishes this task by impaling the target animal, allowing the fishermen to use a rope or chain attached to the butt of the projectile to catch the animal...
s specifically designed for catching large whales. Although initially cumbersome and with a low success rate, Foyn perfected the harpoon gun, and soon several whaling stations were established on the coast of
Finnmarkor Finnmárku is a county in the extreme northeast of Norway. By land it borders Troms county to the west, Finland to the south and Russia to the east, and by water, the Norwegian Sea to the northwest, and the Barents Sea to the north and northeast.The county was formerly known as Finmarkens...
in northern
NorwayNorway , officially the Kingdom of Norway, is a country in Northern Europe occupying the western portion of the Scandinavian Peninsula, as well as Jan Mayen and the Arctic archipelago of Svalbard under the Spitsbergen Treaty...
. Because of disputes with the local fishermen, the last whaling station in Finnmark was closed down in 1904.
Soon, Blue Whales were being hunted in
IcelandThe Republic of Iceland is a European island country located in the North Atlantic Ocean. It has a population of about 320,000 and a total area of 103,000 km². Its capital and largest city is Reykjavík, whose surrounding area is home to approximately two thirds of the national population...
(1883), the
Faroe IslandsThe Faroe Islands, sometimes Faeroe Islands, Faroe, or Faeroes are an island group situated between the Norwegian Sea and the North Atlantic Ocean, approximately halfway between Scotland and Iceland...
(1894), Newfoundland (1898), and
SpitsbergenSpitsbergen is a Norwegian island, the largest island of the Svalbard archipelago in the Arctic Ocean. The island of Spitsbergen covers approximately 39,044 km²...
(1903). In 1904-05 the first Blue Whales were taken off South Georgia. By 1925, with the advent of the stern slipway in factory ships and the use of steam-driven whale catchers, the catch of Blue Whales, and baleen whales as a whole, in the Antarctic and sub-Antarctic began to increase dramatically. Between 1930 and 1931, these ships killed 29,400 Blue Whales in the Antarctic alone. By the end of
World War IIWorld War II, or the Second World War , was a global military conflict which involved a majority of the world's nations, including all great powers, organized into two opposing military alliances: the Allies and the Axis...
, populations had been significantly depleted, and, in 1946, the first quotas restricting international trade in whales were introduced, but they were ineffective because of the lack of differentiation between species. Rare species could be hunted on an equal footing with those found in relative abundance.
Blue Whale hunting was banned in the 1960s by the
International Whaling CommissionThe International Whaling Commission is an international body set up by the terms of the International Convention for the Regulation of Whaling , which was signed in Washington, D.C...
, and illegal whaling by the USSR finally halted in the 1970s, by which time 330,000 Blue Whales had been killed in the Antarctic, 33,000 in the rest of the Southern Hemisphere, 8,200 in the North Pacific, and 7,000 in the North Atlantic. The largest original population, in the Antarctic, had been reduced to 0.15% of their initial numbers.
Population and distribution today
Since the introduction of the whaling ban, studies have failed to ascertain whether the
conservation reliantConservation reliant species are endangered or threatened animal or plant species that require continuing species specific wildlife management intervention such as predator control, habitat management and parasite control to survive even when self-sustaining population recovery goals are...
global Blue Whale population is increasing or remaining stable. In the Antarctic, best estimates show a significant increase at 7.3% per year since the end of illegal Soviet whaling, but numbers remain at under 1% of their original levels. It has also been suggested that Icelandic and Californian populations are increasing but these increases are not statistically significant. The total world population was estimated to be between 5,000 and 12,000 in 2002, although there are high levels of uncertainty in available estimates for many areas.
The
IUCN Red ListThe IUCN Red List of Threatened Species , founded in 1948, is the world's most comprehensive inventory of the global conservation status of plant and animal species. The International Union for the Conservation of Nature and Natural Resources is the world's main authority on the conservation...
counts the Blue Whale as "endangered" as it has since the list's inception. In the
United StatesThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
, the
National Marine Fisheries ServiceThe U.S. National Marine Fisheries Service is a United States federal agency. A division of the National Oceanic and Atmospheric Administration and the Department of Commerce, NMFS is responsible for the stewardship and management of the nation's living marine resources and their habitat within...
lists them as endangered under the
Endangered Species ActThe Endangered Species Act of 1973 is the most wide-ranging of the dozens of United States environmental laws passed in the 1970s...
. The largest known concentration, consisting of about 2,000 individuals, is the North-East Pacific population of the Northern Blue Whale (
B. m. musculus) subspecies that ranges from
AlaskaAlaska is the largest state of the United States of America by area; it is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...
to
Costa RicaCosta Rica, officially the Republic of Costa Rica is a country in Central America, bordered by Nicaragua to the north, Panama to the east and south, the Pacific Ocean to the west and south and the Caribbean Sea to the east.Costa Rica, which translates literally as "Rich Coast", constitutionally...
but is most commonly seen from California in summer. Infrequently, this population visits the North-West Pacific between
KamchatkaThe Kamchatka Peninsula is a 1,250-kilometer long peninsula in the Russian Far East, with an area of 472,300 km². It lies between the Pacific Ocean to the east and the Sea of Okhotsk to the west...
and the northern tip of Japan.
In the North Atlantic, two stocks of
B. m. musculus are recognized. The first is found off
GreenlandGreenland is an autonomous constituent country within the Kingdom of Denmark located between the Arctic and Atlantic Oceans, east of the Canadian Arctic Archipelago...
,
NewfoundlandNewfoundland and Labrador is a province of Canada on the country's Atlantic coast in northeastern North America. This easternmost Canadian province comprises two main parts: the island of Newfoundland off the country's eastern coast, and Labrador on the mainland to the northwest of the island.A...
,
Nova ScotiaNova Scotia is a Canadian province located on Canada's southeastern coast. It is the most populous province in Atlantic Canada. Its capital, Halifax, is a major economic centre of the region. Nova Scotia is the second-smallest province in Canada with an area of...
and the
Gulf of Saint LawrenceThe Gulf of Saint Lawrence , the world's largest estuary, is the outlet of North America's Great Lakes via the Saint Lawrence River into the Atlantic Ocean. It is a semi–enclosed sea, covering an area of about 236 000 km2 and containing 35000 km3 of water...
. This group is estimated to total about 500. The second, more easterly group is spotted from the
AzoresThe Azores is a Portuguese archipelago in the Atlantic Ocean, about from Lisbon and about from the east coast of North America. The two westernmost Azorean islands actually lie on the North American plate...
in spring to Iceland in July and August; it is presumed that the whales follow the
Mid-Atlantic RidgeThe Mid-Atlantic Ridge is a mid-ocean ridge, a divergent tectonic plate boundary located along the floor of the Atlantic Ocean, and the longest mountain range in the world. It separates the Eurasian Plate and North American Plate in the North Atlantic, and the African Plate from the South American...
between the two volcanic islands. Beyond Iceland, Blue Whales have been spotted as far north as
SpitsbergenSpitsbergen is a Norwegian island, the largest island of the Svalbard archipelago in the Arctic Ocean. The island of Spitsbergen covers approximately 39,044 km²...
and
Jan MayenJan Mayen Island is a volcanic island in the Arctic Ocean, 55 km long and 373 km
2 in area, partly covered by glaciers . It has two parts: larger northeast Nord-Jan and smaller Sør-Jan, linked by an isthmus 2.5 km wide...
, though such sightings are rare. Scientists do not know where these whales spend their winters. The total North Atlantic population is estimated to be between 600 and 1,500.
In the Southern Hemisphere, there appear to be two distinct subspecies,
B. m. intermedia, the Antarctic Blue Whale, and the little-studied Pygmy Blue Whale,
B. m. brevicauda, found in Indian Ocean waters. The most recent surveys (midpoint 1998) provided an estimate of 2,280 blue whales in the Antarctic., of which fewer than 1% are likely to be pygmy blue whales Estimates from a 1996 survey were that 424 Pygmy Blue Whales were in a small area south of
MadagascarMadagascar, or Republic of Madagascar , is an island nation in the Indian Ocean off the southeastern coast of Africa. The main island, also called Madagascar, is the fourth-largest island in the world, and is home to 5% of the world's plant and animal species, of which more than 80% are endemic to...
alone, thus it is likely that numbers in the entire Indian Ocean are in the thousands. If this is true, the global numbers would be much higher than estimates predict.
A fourth subspecies,
B. m. indica, was identified by
BlythEdward Blyth was an English zoologist and pharmacist. He was one of the founders of Indian zoology....
in 1859 in the northern Indian Ocean, but difficulties in identifying distinguishing features for this subspecies led to it being used a synonym for
B. m. brevicauda, the Pygmy Blue Whale. Records for Soviet catches seem to indicate that the female adult size is closer to that of the Pygmy Blue than
B. m. musculus, although the populations of
B. m. indica and
B. m. brevicauda appear to be discrete, and the breeding seasons differ by almost six months.
Migratory patterns of these subspecies are not well known. For example, Pygmy Blue Whales have been recorded in the northern Indian Ocean (
OmanOman , officially the Sultanate of Oman , is an Arab country in southwest Asia on the southeast coast of the Arabian Peninsula. It borders the United Arab Emirates on the northwest, Saudi Arabia on the west and Yemen on the southwest....
,
MaldivesThe Maldives , or Maldive Islands, officially Republic of Maldives, is an island country in the Indian Ocean formed by a double chain of twenty-six atolls stretching along north-south direction off India's Lakshadweep islands, between Minicoy Island and Chagos Archipelago...
,
Sri LankaSri Lanka , officially the Democratic Socialist Republic of Sri Lanka , is an island country in South Asia, located about off the southern coast of India...
), where they may form a distinct resident population. In addition, the population of Blue Whales occurring off
ChileChile, officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...
and
PeruPeru , officially the Republic of Peru , is a country in western South America. It is bordered on the north by Ecuador and Colombia, on the east by Brazil, on the southeast by Bolivia, on the south by Chile, and on the west by the Pacific Ocean.Peruvian territory was home to the Norte Chico...
may also be a distinct population. Some Antarctic Blue Whales approach the eastern South Atlantic coast in winter, and occasionally, their vocalizations are heard off Peru, Western Australia, and in the northern Indian Ocean. In Chile, the
Cetacean Conservation CenterThe Cetacean Conservation Center is a Chilean NGO dedicated to the conservation of cetaceans and other marine mammals that inhabit the coastal waters of Chile...
, with support from the
Chilean Navy-History:The origin of the Chilean Navy dates back to 1817. A year before, following the Battle of Chacabuco, General Bernardo O'Higgins prophetically declared "this victory and another hundred shall be of no significance if we do not gain control of the sea"....
, is undertaking extensive research and conservation work on a recently discovered feeding aggregation of the species off the coast of
Chiloe IslandChiloé Island , also known as Greater Island of Chiloé , is the largest island of Chiloé Archipelago off the coast of Chile, in the Pacific Ocean. The island is located in southern Chile, in the Los Lagos Region...
in an area named "Golfo del Corcovado", where 326 Blue Whales were spotted in the summer of 2007.
Efforts to calculate the Blue Whale population more accurately are supported by marine mammologists at
Duke UniversityDuke University is a private research university located in Durham, North Carolina, United States. Founded by Methodists and Quakers in the present-day town of Trinity in 1838, the school moved to Durham in 1892...
who maintain the OBIS-SEAMAP (Ocean Biogeographic Information System—Spatial Ecological Analysis of Megavertebrate Populations), a collation of marine mammal sighting data from around 130 sources.
Threats other than hunting
Due to their enormous size, power and speed, adult Blue Whales have virtually no natural predators. There is, however, one documented case in
National Geographic MagazineThe National Geographic Magazine, later shortened to National Geographic, is the official journal of the National Geographic Society. It published its first issue in 1888, just nine months after the Society itself was founded...
of a Blue Whale being attacked by
OrcaThe Killer Whale or Orca , or less commonly, Blackfish, is the largest species of the dolphin family. Most people think that they are whales, but they are actually dolphins. They are called killer whales often because they sometimes hunt whales for food...
s; although the Orcas were unable to kill the animal outright during their attack, the Blue Whale sustained massive wounds and probably died as a result of them shortly after the attack.
Blue Whales may be wounded, sometimes fatally, after colliding with ocean vessels as well as becoming trapped or entangled in fishing gear. The ever-increasing amount of ocean noise, including
sonarActive sonar may harm marine animals, although the precise mechanisms for this are not well understood. Some marine animals, such as whales and dolphins, use echolocation systems, sometimes called biosonar to locate predators and prey...
, drowns out the vocalizations produced by whales, which may make it harder for them to communicate. Human threats to the potential recovery of Blue Whale populations also include accumulation of
polychlorinated biphenylPolychlorinated biphenyls are a class of organic compounds with 1 to 10 chlorine atoms attached to biphenyl, which is a molecule composed of two benzene rings. The chemical formula for PCBs is C12H10-xClx, where x = 1-10. PCBs were widely used for many...
(PCB) chemicals within the whale's body.
With
global warmingGlobal warming is the increase in the average temperature of the Earth's near-surface air and oceans since the mid-20th century and its projected continuation. Global surface temperature increased 0.74 ± 0.18 °C during the last century...
causing glaciers and permafrost to melt rapidly and allowing a large amount of fresh water to flow into the oceans, there are concerns that if the amount of fresh water in the oceans reaches a critical point, there will be a disruption in the
thermohaline circulationThe term thermohaline circulation refers to the part of the large-scale ocean circulation that is driven by global density gradients created by surface heat and freshwater fluxes....
. Considering the Blue Whale's migratory patterns are based on ocean temperature, a disruption in this circulation, which moves warm and cold water around the world, would be likely to have an effect on their migration. The whales summer in the cool, high latitudes, where they feed in
krillKrill is a type of shrimp-like marine invertebrate animal. These small crustaceans are important organisms of the zooplankton, particularly as food for baleen whales, manta rays, whale sharks, crabeater seals, and other seals, and a few seabird species that feed almost exclusively on them. Another...
-abundant waters; they winter in warmer, low latitudes, where they mate and give birth.
The change in ocean temperature would also affect the Blue Whale's food supply. The warming trend and decreased salinity levels would cause a significant shift in krill location and abundance.
Museums
The Natural History Museum in
London[]London is the capital of England and the United Kingdom. It has been a major settlement for two millennia, and the history of London goes back to its founding by the Romans, when it was named Londinium. London's core, the ancient City of London, the 'square mile', retains its medieval boundaries...
contains a famous mounted skeleton and life-size model of a Blue Whale, which were both the first of their kind in the world but have since been replicated at the
University of California, Santa CruzThe University of California, Santa Cruz, also known as UC Santa Cruz or UCSC, is a public, collegiate university; one of ten campuses in the University of California...
. Similarly, the
American Museum of Natural HistoryThe American Museum of Natural History , located on the Upper West Side, Manhattan, New York, USA, is one of the largest and most celebrated museums in the world...
in
New York CityNew York is the most populous city in the United States, and the center of the New York metropolitan area, which is among the most populous urban areas in the world. A leading global city, New York exerts a powerful influence over worldwide commerce, finance, culture, fashion and entertainment...
has a full-size model in its Milstein Family Hall of Ocean Life.
The
Aquarium of the PacificThe Aquarium of the Pacific is a 5013 non-profit aquarium located on a site on Rainbow Harbor in Long Beach, California...
in
Long Beach, CaliforniaLong Beach is a large city located in southern California, USA, on the Pacific coast. It is situated in Los Angeles County, about south of downtown Los Angeles. Long Beach borders Orange County on its southeast edge....
features a life-size model of a mother Blue Whale with her calf suspended from the ceiling of its main hall.
Whale-watching
Living Blue Whales may be encountered on whale-watching cruises in the
Gulf of MaineThe Gulf of Maine is a large gulf of the Atlantic Ocean on the northeastern coast of North America.It is delineated by Cape Cod at the eastern tip of Massachusetts in the southwest and Cape Sable at the southern tip of Nova Scotia in the northeast. It includes the entire coastlines of the U.S...
and are the main attractions along the north shore of the
Gulf of Saint LawrenceThe Gulf of Saint Lawrence , the world's largest estuary, is the outlet of North America's Great Lakes via the Saint Lawrence River into the Atlantic Ocean. It is a semi–enclosed sea, covering an area of about 236 000 km2 and containing 35000 km3 of water...
and in the Saint Lawrence estuary.
External links
{{Commons
|Balaenoptera musculus}}
{{Wikispecies
|Balaenoptera musculus}}
{{Spoken Wikipedia|Blue whale.ogg|2006-04-13}}
{{Cetacea|M.}}
{{featured article}}