Blue whales (Balaenoptera musculus) is a marine mammal belonging to the suborder of baleen whales. Its length reaches more than 33 meters and mass were recorded at 181 tons or more. The animal is believed to be the largest animal ever known.
Pope has a long and slender back (dorsal) colored bluish gray and the front (ventral) lighter. There are at least three blue whale subspecies: B. m. musculus in the North Atlantic and North Pacific, B. m. intermedia in the Southern Ocean and B. m. brevicauda (also called the pygmy blue whale) in the Indian Ocean and South Pacific Ocean. B. m. indica who live in the Indian Ocean may be the other subspecies. As with other baleen whales, blue whales are the staple food of tiny crustaceans called krill. Blue whales were abundant in nearly all oceans until the beginning of the 20th century. For more than a century, these whales were hunted almost to extinction before being protected by the international community in 1966. According to a report in 2002, there were approximately 5,000 to 12,000 blue whales worldwide which is divided into at least five groups. Recent research subspecies of pygmy blue whale indicate that these estimates may be too low. Before the whaling, the largest population was in the Antarctic, numbering approximately 239,000 (between 202 000 to 311 000). Currently the concentration of groups in the eastern North Pacific Ocean, Antarctica, and the Indian Ocean is much lower than the previous figure (approximately 2,000). There are also two other groups in the North Atlantic Ocean, and at least two more groups in the Southern Hemisphere.
Taxonomy.
Blue whales are part of the family Balaenopteridae, which also includes the humpback whales, fin whales, Bryde's, sei whales and minke whales. Evolutionarily, family Balaenopteridae believed to be separate from the other whales in the suborder Mysticeti pad Oligocene. It is not yet known when these family members are separated from each other.
The blue whale is usually classified as one of eight species of whale in the genus Balaenoptera. There are also experts who put this whale in the genus Sibbaldus, although this classification is not approved. Circuit analysis of deoxyribonucleic acid (DNA) show that the blue whale Phylogenetic closer to the sei whales (Balaenoptera borealis) and Bryde's (Balaenoptera brydei) than the species Balaenoptera other, and closer to the humpback whale (Megaptera) and gray whales (Eschrichtius ) rather than a minke whale (Balaenoptera acutorostrata and Balaenoptera bonaerensis). If further research to make sure this relationship, Balaenopteridae family may need to be reclassified.
The phylogenetic tree of animals related to blue whales.
Recorded at least eleven cases of a cross between the blue whale fin whale in the wild. According Arnason and Gullberg, the genetic distance between the blue whale with whale fins more or less similar to the distance between humans and gorillas. Meanwhile, some researchers who served in Fiji reported that they have perpetuated the image of the pope result of a cross between blue whales and humpback whales.
First description of a blue whale was made by Robert Sibbald in his work entitled Phalainologia Nova (1694). On September 1692, Sibbald found a blue whale that washed up on the Firth of Forth-a male with a length of 78 feet, which has a "plate of black and horned" and "two large openings that looks almost like a pyramid."
The specific name musculus is a Latin term that can mean "muscular", but it can also be translated into "little mouse". Linnaeus, who named this species in the Systema Naturae in 1758, may be aware of this and intends to make it as an irony. This species is also called sulfur-bottom (bottom sulfur) by Herman Melville in his novel Moby-Dick because the bottom of the orange-brown or yellow tinge caused by diatoms in the skin. Another name that has been used is rorquals Sibbald (named after Sir Robert Sibbald), the giant blue whale and the great northern rorqual. The names are now no longer used. The term blue whale was first used in the novel Moby Dick, which is simply called it in passing and did not relate specifically to this species. The name comes from the Norwegian word blåhval, triggered by Svend Foyn after complete his harpoon guns; a Norwegian scientist named GO Sars makes it a common name in Norwegian in 1874.
Experts divide the species into three or four subspecies :
- B. m. musculus, northern blue whale consisting of the population in the North
Atlantic and
North Pacific.
- B. m. intermedia; southern blue whales that live in the Southern Ocean.
- B. m. brevicauda, the pygmy blue whale can be found in the Indian Ocean and the Pacific South.
- B. m. indica, the Indian rorquals major who also lives in the Indian Ocean,
although this classification is still controversial because it may be a subspecies
the same subspecies B. m. brevicauda.
Description and behavior.
The blue whale has a long body and appear stretched when compared with other whale's body. Flat head, shaped like the letter U, and have backs that extends from the blowhole to the part of the upper lip. The front of the mouth filled with baleen plates (there are about 300 plates, and each length of about one meter) hanging in the upper jaw. Between 70 to 118 grooves (called ventral plate) runs along parallel to the length of the neck and body. This plate helps remove water from the mouth after eating (see how to eat below).
The whale's dorsal fin is small and ranges between 8-70 centimeters (3.1 to 28 in) (usually 20-40 centimeters (7.9 to 16 in)) with an average of 28 Centimetres (11 in). This fin shape varies; some just a blob that is hardly noticeable, while others have a prominent dorsal and shaped like a crescent. When heading to the surface to breathe, blue whales shrugged and spat holes in the surface of the range is greater than other large whales such as whale fin or sei whale. This characteristic can be used by researchers to distinguish species of whales. Some blue whales in the North Atlantic and North Pacific raised the tip of its tail when diving. When breathing, the whale emit bursts of vertical columns that can reach 12 meters (39 ft) (typically 9 meters (30 ft)). Lung capacity is 5,000 liters. Blue Whale also has double blowholes shielded by a large splashguard so that water does not enter while breathing.
Long front flippers blue whale approximately between three and 3-4 meters (9.8-13.1 ft). Its upper part is gray with a thin white borders, while the lower part is white. Head and tail are generally gray. The top of the blue whale, and sometimes the front flippers, normally has a mottled. The striped levels vary in each individual. Some may be colored bluish gray color entirely, while others show the variation of dark blue, gray, or black, filled with dappled.
Blue whales can reach speeds of 50 kilometres per hour (31 mph) (usually when interacting with other whales), but the speed is usually only 20 kilometres per hour (12 mph). When eaten, the speed is reduced to 5 kilometres per hour (3.1 mph).
Blue whales mostly live alone or with other individuals. It is unknown how long the whales live together. In place of an abundance of food, there are 50 blue whales in a small area. However, they do not form a large group (unlike other baleen whales).
Size.
The blue whale is believed to be the largest animal ever known. In comparison, the largest dinosaur known from the Mesozoic, the Argentinosaurus, whose mass is estimated at 90 tonnes, although Amphicoelias fragillimus vertebrate suspected of having masses of 122 tons and a length of 40-60 meters (which is controversial).
The blue whale weighed difficult because of their large size. Like most hunted whale, blue whale adult has never been weighed whole, but cut up in advance, so that the approximate mass of the whale becomes too low due to lack of blood and other fluids. Overall, the blue whales of the North Atlantic and Pacific appears to be smaller than whales in sub-Antarctic waters. However, the mass of the pope whose length reaches 27 meters (89 ft) registered between 150-170 tons. Mass whale length 30 meters (98 ft) according to the National Marine Mammal Laboratory (NMML) excess of 180 tons. The largest blue whale ever weighed accurately by scientists NMML is a female whose mass is 177 tons.
Data about the biggest blue whale ever still uncertain because most of the data come from blue whales killed in Antarctic waters during the early 20th century, which does not conform to the standard zoological measurement. Massa largest whale ever recorded was 190 tonnes, while the title of the longest whale won two berina measuring 33.6 meters (110 ft) and 33.3 meters (109 ft). The longest blue whale measured by scientists at the US NMML was a female caught in Antarctica by Japanese hunters in the year 1946-1947, with a length of 29.9 m. When he was an inspector of whaling on board Ulysses, he made sure measurements pregnant blue whales caught in the Antarctic in 1937-1938 with a length of 30 m (98 ft). [28] The longest whale ever found in North Pacific is a female along 27.1 meters (89 ft) were captured by the Japanese hunters in 1959, while the longest in the North Atlantic is a female with a length of 28.1 meters (92 ft) which is caught in the Davis Strait.
Because of its large size, multiple organ blue whale is the largest in the kingdom animalia. Tongue blue whale has a mass of about 2.7 tonnes and, when it is fully open, the mouth is estimated large enough to accommodate more than 90 tons of food and water. Although big mouth, throat size small and unable to swallow objects bigger than a beach ball. Heart mass of 600 kilograms (1,300 lb) and is the largest among the animals. Blue whale aortic diameter of about 23 cm. During the first 7 months of life, a baby blue whale gain body mass quickly, up to 90 kilograms (200 lb) every 24 hours. Even at birth, the mass was recorded at 2,700 kilograms (6,000 lb) -Same with adult hippopotamus. Blue whale brain is relatively small, with a mass of about 6.92 kilograms (15:26 lb), or only 0.007% of his body mass. Meanwhile, penis blue whale is the largest of all living organisms.
Food.
The staple food of blue whales is krill, though they also eat copepods in small quantities. Zooplankton species is eaten by various blue whale from one ocean to ocean. In the North Atlantic, Meganyctiphanes norvegica, thysanoessa raschii, thysanoessa inermis and thysanoessa longicaudata is common foods. In the South Pacific, Euphausia Pacifica, thysanoessa inermis, thysanoessa longipes, thysanoessa spinifera, Nyctiphanes simplex and Nematoscelis megalops; in the Antarctic Euphausia superba, Euphausia euphausia crystallorophias and vallentini.
Adult blue whale can eat krill as many as 40 million per day. They always eat in areas with high concentrations of krill, so sometimes it takes approximately 3,600 kilograms (7,900 lb) of krill in a single day. The energy needs of adult blue whales in one day to be in the range of 1.5 million kilocalories. Their seasonal feeding behavior. Blue whales filling their bellies in waters rich in krill in the Antarctic before migrating to breeding grounds in warmer waters and less rich in krill near the equator. Blue whales can receive energy 90 times greater than released, so it has large energy reserves.
Because krill move, blue whales usually eat at depths greater than 100 meters (330 ft) during the day and at the surface at night. Dive time is estimated at about 10 minutes while eating, although many are diving within 20 minutes. Blue whales eat the krill group crashing, so swallowing krill and water in large quantities. Pressure from the pouch and tongue then push the water out through the baleen plates. Once the water removed from the mouth, the remaining krill swallowed because they could not pass through the plate. Blue whales are also sometimes eat small fish, crustaceans and squid caught up with krill.
The history of life.
The breeding season begins in late fall and continue until the end of winter. Mating behavior or breeding ground for blue whales are not widely known. Females usually give birth every two to three years at the beginning of winter after a gestation period of ten to twelve months. Massa child blue whale is usually about two and a half tons and a length of about 7 meters (23 ft). Child blue whale drink 380-570 liters of milk every day, and the blue whale milk contains an energy of 18,300 kJ / kg (4,370 kcal / kg). After six months, the child disapihkan blue whale, and then its length will double. Sexual maturity is usually attained at the age of five to ten years. In the Northern Hemisphere, according to whaling records, the average length of a blue whale males that have reached sexual maturity is 20-21 m (65.6 to 69 ft), and for females 21-23 m (69-75 ft), while in the Southern Hemisphere, for males the average length of 22.6 m (74 ft) and for females 24 m (79 ft). In the Northern Hemisphere, the average length of an adult blue whale is 24 m (79 ft) and females 25 m (82 ft), while in the Southern Hemisphere male average length of 25 m (82 ft) and for females 26.5 m ( 87 ft). In the North Pacific, fotogrametik studies have shown that adult blue whale is the average length of 21.6 m (71 ft), with a maximum length of 24.4 m (80 ft) - though the female whale of a 26.5 m (87 ft) ever found stranded in Pescadero, California, in 1979.
Scientists estimate that blue whales can reach the age of 80 years; however, because the track record of the individual does not come from the hunt, it is not known with certainty. The only natural predator is the killer whale blue whale. According to the study, as many as 25% of an adult blue whale had wounds caused by the attack of killer whales. The death rate of the attack is still unknown.
Rare blue whale washed ashore, and the blue whale never stranded en masse because of the social structure of this species. As soon as the blue whale stranded, they can be a common concern. In 1920, a blue whale washed ashore near bragar on the island of Lewis, Outer Hebrides, Scotland. The previous Pope was shot by a hunter, but his harpoon fails to explode. The pope then instinct is to continue to breathe, despite having stranded so as not to drown. Two blue whale bone was set up in the main street of Lewis and now a tourist destination.
Vocalizations.
Based on the estimate made by Cummings and Thompson (1971), when measured relative to the pressure of the mikropaskal within one meter, the sound pressure created by the blue whale was recorded between 155 to 188 decibels. The whole group of blue whale calls on the fundamental frequency between 10 to 40 Hz; as a comparison, the lowest frequency that can be heard by humans is 20 Hz. Blue whale calls can last anywhere from ten to thirty seconds. Blue whales on the waterfront Sri Lanka is reported to have repeatedly making "songs" of four notes which lasted for two minutes. Because the phenomenon is so far not found among other populations, researchers believe that singing is a characteristic of the subspecies B. m. brevicauda.
The reason the blue whale makes vocalizations is still unknown.
Richardson et al (1995) mentions six possibilities:
- Keeping the distance between individuals
- Identifying the species and the individual
- Transmit contextual information (such as food, warning, courtship)
- Maintain social organization (eg a call between a female and male)
- Recognize the appearance of topographic
- Finding food
Population and whaling.
Hunting period.
Blue whale populations have been reduced drastically due to commercial whaling.
Blue whales are not easily captured or killed. Thanks to the speed and strength, whalers at first rarely pursue them and choose to hunt sperm whales and right whales. In 1864, Svend Foyn of Norway equip a steamboat with harpoons designed to capture large whales. Although initially difficult and a low success rate, Foyn enhance the harpoon guns and then some whaling station was established on the coast of Finnmark in northern Norway. Because the odds of view of the local fishermen, the last whaling station in Finnmark was closed in 1904.
The blue whale then began to be hunted in Iceland (1883), the Faroe Islands (1894), Newfoundland (1898), and Spitsbergen (1903). In 1904-05, the first blue whales were caught in South Georgia. In 1925, with the stern slipway and use steam-powered whalers, whaling blue (and all the baleen whales) in the Antarctic and sub-Antarctic has increased dramatically. In the year 1930-31 hunting season, the vessel capturing 29,400 blue whales in the Antarctic. At the end of World War II, the blue whale population was reduced drastically, and in 1946 the pope trade quota limit set, but is not effective because there is no differentiation between species. Rare species can be hunted like species relatively numerous.
Hunting of blue whales was banned by the International Whaling Commission in 1962, and which carried out illegal whaling by the USSR finally halted in the 1970s. At that time, 330,000 blue whales caught in the Antarctic, 33,000 in the Southern Hemisphere, 8,200 in the North Pacific, and 7,000 in the North Atlantic. Population in Antarctica numbers have dwindled to only 0.15% of their initial amount remaining.
Population and distribution today.
Since the enactment of the prohibition of whaling, the research can not be sure whether global blue whale population increased or remained stable. In Antarctica, according to the most optimistic estimates, the population increased by 7.3% per year after the end of illegal Soviet whaling, but their number remained below 1% of the previous amount. Population in Iceland and California may also increase, but the increase was not significant. Total population of blue whales in the world is estimated at between 5,000 to 12,000 in 2002, although many estimates are still uncertain. In the IUCN Red List, the blue whale species classified as "endangered". Meanwhile, in the United States, National Marine Fisheries Service consider the blue whale as an endangered species under the Endangered Species Act (Endangered Species Act).
The largest concentration of blue whales were in the Northeast Pacific. The whale group consists of 2,800 individuals and belong to the subspecies. They are scattered from Alaska to Costa Rica, but usually can be seen in California in the summer. Sometimes this population to visit Pacific northwest, between the Kamchatka Peninsula and the northern tip of Japan. Meanwhile, in the North Atlantic, there are two groups of B. m. musculus. The first group can be found on the coast of Greenland, Newfoundland, Nova Scotia and the Gulf of Saint Lawrence. The group is estimated to number around 500 birds. The second group is spread from the Azores in spring to Iceland in July and August; The pope is expected to follow the back Middle Atlantic ocean that lies between the volcanic island. Outside Iceland, blue whales can be found in the far north as Spitsbergen and Jan Mayen, though rarely seen. Scientists do not know where these whales through the winter. Overall, the number of North Atlantic population ranges between 600 and 1500.
In the Southern Hemisphere, it seems there are two different subspecies, namely B. m. intermedia (southern blue whale) and B. m. brevicauda, pygmy blue whale. According to a recent survey (mid-1998), there were an estimated 2,280 blue whales in Antarctica (and less than 1% of which may be a blue whale dwarf. Based on the estimates of the survey in 1996, there were 424 blue whales dwarf in south Madagascar, [69] so most likely the numbers in the Indian Ocean about thousands. If this is true, the number of global blue whale is much higher than expected.
The fourth subspecies, B. m. indica, was identified by Blyth in 1859 in the northern Indian Ocean. However, because of the difficulty in finding different characteristics, this subspecies is synonymous with B. m. brevicauda, pygmy blue whale. According to arrest records Soviet, the size of a blue whale is closer to the size of an adult female pygmy blue whale than B. m. musculus, although the population of B. m. indica and B. m. brevicauda apparently separate and distinct mating season (the difference is almost six months).
Blue whale migration patterns are not widely known. For example, pygmy blue whales have been found in the northern Indian Ocean (Oman, Maldives, Sri Lanka), and perhaps they form different populations. In addition, the population of blue whales near Chile and Peru may also be a distinct population. Some Antarctic blue whales approach the eastern South Atlantic coast in winter, and occasionally their vocalizations are heard in Peru, Western Australia, and in the northern Indian Ocean. In Chile, Cetacean Conservation Center, which is supported by the Chilean Navy, conducting research and conservation of species of blue whales on the coast of Chiloe Island, Gulf of Corcovado, because there was found 326 blue whales in 2007.
Efforts calculate the blue whale population more accurately are supported by marine mammal expert at Duke University, who make-SEAMAP OBIS (Ocean Biogeographic Information System - Spatial Ecological Analysis of Megavertebrate Populations), a collection of surveillance data for marine mammals from about 130 sources.
Threats other than hunting.
Due to the size, strength, and speed, adult blue whales have no natural predators. However, as reported by the National Geographic Magazine, there is a case of blue whales are attacked by killer whales in Baja California Peninsula; although these attacks did not kill him, the blue whale suffered serious injury and possible death because of it. Up to a quarter of blue whales in Baja bore the scars of a killer whale attack.
Blue whales may be injured (sometimes fatal) after colliding with ships or trapped in fishing gear. Increased noise in the ocean (including those caused by sonar) obscure vocalizations made by the pope, so they are more difficult to communicate. Blue whales stopped producing the so call sonar is activated, even if the frequency sonar (1-8 kHz) far exceeds their sound frequencies (25-100 Hz). Another threat comes from humans is the accumulation of chemicals polychlorinated biphenyls (PCBs) in the body of the whale.
Global warming is also melting glaciers and permanent ice, so a lot of fresh water flowing into the ocean. It is feared that if the amount of fresh water exceeds the limit, there will be a disruption of the thermohaline circulation (circulation of warm and cold water flow to the rest of the world). Because blue whale migration patterns depend on the temperature of the ocean, the disruption of the circulation will disrupt their migration patterns. Moreover, changes in ocean temperature would disrupt food supplies blue whale. The warming trend and decreased salinity can change the number and location of krill.
Museum.
Natural History Museum which is located in London store framework and model of a blue whale, which is the first in the world, which is replicated in Univeritas California, Santa Cruz. Similarly, the American Museum of Natural History in New York City who has a model of a blue whale in the Milstein Family Hall of Ocean Life. Blue whale skeleton child was also installed at the New Bedford Whaling Museum in New Bedford, Massachusetts.
Aquarium of the Pacific in Long Beach, California also showed off a model mother blue whale with her son hanging on the roof of the porch of the main. [80] In addition, the Beaty Biodiversity Museum at the University of British Columbia, Canada, featuring frame blue whale (the skull is a replica) in highway campus, and genuine blue whale skeleton at the Canadian Museum of Nature in Ottawa also began to be exhibited in 2010.
National History Museum in Gothenburg, Sweden has a replica of a blue whale are displayed next to the skeleton. While the Melbourne Museum displays pygmy blue whale skeleton.
Observations.
Blue whales can be found (though rarely) in the whale watching cruise in the Gulf of Maine. While in Chile, Alfaguara project combines Whale conservation and tourism. Thank you for reading this article.
Written and posted by Bambang Sunarno.
sunarnobambang86@gmail.com
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http://primadonablog.blogspot.com/2015/08/the-blue-whale.html
DatePublished: August 27, 2015 at 12.02
Tag : The Blue Whale.
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