Portal:Cetaceans/Selected Article/Archive
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June, 2006
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The Sperm Whale (Physeter macrocephalus) is the largest of all toothed whales and is believed to be the largest toothed animal to ever inhabit Earth, measuring up to 18 m (60 ft) long. (The baleen blue whale is larger, and invertebrates such as the lion's mane jelly fish or the Portuguese man of war may be longer.) The whale was named after the milky-white substance spermaceti found in its head and originally mistaken for sperm. The Sperm Whale's enormous head and distinctive shape, as well as its central role in Herman Melville's Moby-Dick, have led many to describe it as the archetypal whale. Partly due to Melville, the Sperm Whale is commonly associated with the mythological Leviathan of Biblical lore.
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July, 2006
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The International Whaling Commission (IWC) was set up by the International Convention for the Regulation of Whaling (ICRW) on December 2, 1946 to promote and maintain whale fishery stocks. The structural design of the IWC rested on the hope that states in their long-term self-interest would adopt cooperative policies suggested by expert scientific management of a common resource.See Protocol to the International Convention for the Regulation of Whaling, 19 November 1956, 10 UST 952, 338 UNTS 366; Circular Communication to All Contracting Governments, 30 June 1972, 23 UST 2820. Since the 1980s the IWC has become the primary mechanism for the protection of all species of whale.Patricia Birnie, International Regulation of Whaling: From Conservation of Whaling to Conservation of Whales and Regulation of Whale-watching (New York: Oceana Publications, 1985) The change in the IWC's institutional mission began in the early 1970s, and is often linked with the United Nations Conference on the Human Environment at Stockholm in 1972. The result of this shift is most evident in the IWC's adoption of a five-year moratorium on commercial whaling, which commenced in 1986 and has been extended to the present, and in the IWC's recent designation of an Antarctic sanctuary for whales.
The current IWC Commissioners meeting is taking place from 16-20 June 2006 in St. Kitts and Nevis where pro-whaling countries plan to challenge the 1982 moratorium.
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August, 2006
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A dolphinarium is an artificial aquarium for dolphins. The dolphins are kept in a large pool, though occasionally they are also kept in pens, either for research or for public performances. Some dolphinariums consist of little more than one pool where dolphins perform for the public, others have expanded in much larger parks often having more than one pool, keeping other marine animals as well and also having other attractions. These larger parks are often no longer considered to be dolphinariums themselves, but marine mammal parks or other theme parks that also have a dolphinarium. A dolphinarium can also be part of a zoo.
Though cetaceans have been held in captivity in both North America and Europe since the 1860's, dolphins were first kept for paid entertainment in the Marine Studios dolphinarium founded in 1938 in St. Augustine, Florida. It was here that an employee discovered during feeding that dolphins could be trained to perform tricks. Recognizing the success of Marine Studios, more dolphinariums keeping dolphins for entertainment followed.
In the 1960's, keeping dolphins in captivity for entertainment purposes became even more popular after the 1963 Flipper movie and subsequent Flipper television series. In 1966, the first dolphin was exported to Europe. In these early days, dolphinariums could grow quickly due to a lack of legislation and little care for animal welfare. New legislation, most notably the 1972 Marine Mammal Protection Act in the United States, combined with a more critical view on animal welfare forced many dolphinariums around the world to close their doors. As an example, at one point during the early 1970's there were 36 dolphinariums and travelling dolphin shows in the United Kingdom, none of which still exist today, the last dolphinarium in the UK having closed its doors in 1993.
More on Dolphinaria
September, 2006
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Whale watching is the practice of observing whales and other cetaceans in their natural habitat. Whales are watched most commonly for recreation (cf. bird watching) but the activity can also be for scientific or educational reasons. Whilst individuals do organize private trips, whale watching is primarily a commercial activity, estimated to be worth up to $1billion per annum worldwide to whale watching operations and their local communities. The size and rapid growth of the whale watching industry has led to complex and unconcluded debates with the whaling industry about the best use of whales as a natural resource.
Whale watching as an organized activity dates back to 1950 when the Cabrillo National Monument in San Diego was declared a public spot for the observation of Gray Whales. In 1955 the first water-based whale watching commenced in the same area, charging customers $1 per trip to view the whales at closer quarters. The spectacle proved popular, attracting 10,000 visitors in its first year and many more in subsequent years. The industry spread throughout the western coast of the United States over the following decade.
Whale watching today is carried out from the water from crafts from kayaks, motorized rafts, and sailboats through to out-of-use fish or whaling boats and custom-built craft carrying as many as 400 people. Land-based watching of species such as the Orca who come very close to shore remains popular. Viewing of species that usually stay some distance from the shore is also offered by fixed-wing aircraft or helicopters in some areas.
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October, 2006
[edit]The Narwhal (Monodon monoceros) is an Arctic species of cetacean with a body similar to that of a Beluga whale and Irrawaddy Dolphin. It is a rare creature found south of latitude 70°N. It is one of two species of whale in the Monodontidae family (the other is the beluga whale). It is possibly also related to the Irrawaddy dolphin.
The name "Narwhal" is derived from the Old Norse word náhvalr, meaning "corpse man". This probably is a reference to the mottled white and grey colouring of the skin of the adult. It may also refer to the way a narwhal can lie belly up, motionless, for a few minutes at a time. The Narwhal is also commonly known as the moon whale.
The most conspicuous characteristic of male narwhals is their single extraordinarily long tusk, which is a tooth that projects from the left side of the upper jaw and forms a left-handed helix. The tusk can be up to 3 m (nearly 10 ft) long (compared with a body length of 4–5 m [13–16 ft]) and weigh up to 10 kg (22 lb). One in 500 males has two tusks, which occurs when the right tooth, normally small, also grows out. Rarely, a female narwhal may also produce a tusk.
The purpose of the tusk has been the subject of much debate. Early scientific theories supposed that the tusk was used to pierce the ice covering of the narwhal's Arctic Sea habitat. Others suggested the tusk was used in echolocation. More recently, scientists believed the tusk is primarily used for showmanship and for dominance: males with larger tusks are more likely to successfully attract a mate. This hypothesis was suggested by the activity of "tusking", in which two males rub their tusks together.
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November, 2006
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The Fin Whale (Balaenoptera physalus), also called the Finback Whale, is a mammal which belongs to the baleen whales suborder. It is the second largest whale and also the second largest animal living, after the Blue Whale. The Fin Whale can grow to nearly 27 metres (88 ft) long. It is found in all the world's major oceans, and in waters ranging from the polar to the tropical. It is absent only from waters close to the ice pack at both the North and South poles and relatively small areas of water away from the large oceans. The highest population density occurs in temperate and cool waters. The Fin Whale was heavily hunted during the twentieth century and is listed as an endangered species. The International Whaling Commission (IWC) has issued a moratorium on commercial hunting of this whale.
More on the Fin Whale
December, 2006
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The Humpback Whale (Megaptera novaeangliae) is a mammal which belongs to the baleen whale suborder. It is a large whale: an adult usually ranges between 12–16 m (40–50 ft) long and weighs approximately 36,000 kg (79,000 pounds), or 36 tonnes (40 short tons); females, on average, are larger than males. It is well known for its breaching (leaping out of the water), its unusually long front fins, and its complex whale song. The Humpback Whale lives in oceans and seas around the world, and is regularly sought out by whale-watchers. The Humpback Whale is found in all the major oceans, in a wide band running from the Antarctic ice edge to 65° N latitude. It is a migratory species, spending its summers in cooler, high-latitude waters, but mating and calving in tropical and sub-tropical waters.
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January, 2007
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The 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. The Sei Whale migrates annually from cool and subpolar waters in summer to temperate and subtropical waters for winter, although in most areas the exact migration routes are not well known.
The whales reach lengths of up to 20 metres (66 ft) long and weigh up to 45 tonnes (50 tons). It consumes an average of 900 kilograms (2,000 lb) of food each day, primarily copepods and krill, and other zooplankton. It is among the fastest of all cetaceans, and can reach speeds of up to 50 kilometres per hour (31 mph) over short distances.
Following large-scale commercial hunting of the species between the late-nineteenth and late-twentieth centuries when over 238,000 individuals were taken, the Sei Whale is now an internationally protected species, although limited hunting still occurs under controversial research programmes conducted by Iceland and Japan. As of 2006, the worldwide population of the Sei Whale was about 54,000, about a fifth of its pre-whaling population.
More on the Sei Whale
February, 2007
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The Orca or Killer Whale (Orcinus orca) is the largest species of the oceanic dolphin family (Delphinidae). It is found in all the world's oceans, from the frigid Arctic and Antarctic regions to warm, tropical seas. Orcas are highly social and generally travel in stable, matrilineal family groups.
Orcas are versatile predators, with some populations feeding mostly on fish and others on other marine mammals, including large whales. Wild orcas are usually not considered a threat to humans. There have, however, been isolated reports of captive orcas attacking their handlers at marine theme parks.
The orca is the sole species in the genus Orcinus. It is one of thirty-five species in the dolphin family. Like the Sperm Whale genus Physeter, Orcinus is a genus with a single, abundant species with no immediate relatives from a cladistic point of view, thus paleontologists believe that the orca is a prime candidate to have an anagenetic evolutionary history — that is the evolution of ancestral to descendant species without splitting of the lineage. If true, this would make the orca one of the oldest dolphin species, although it is unlikely to be as old as the family itself, which is known to date back at least five million years.
More on the Orca
March, 2007
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Whale song is the sound made by whales to communicate. The word "song" is used in particular to describe the pattern of regular and predictable sounds made by some species of whales (notably the humpback) in a way that is reminiscent of human singing.
The mechanisms used to produce sound vary from one family of cetaceans to another. Marine mammals, such as whales, dolphins, and porpoises, are much more dependent on sound for communication and sensation than land mammals are , as other senses are of limited effectiveness in water. Sight is limited for marine mammals because of the way water absorbs light. Smell is also limited, as molecules diffuse more slowly in water than air, which makes smelling less effective. In addition, the speed of sound in water is roughly four times that in the atmosphere at sea level. Because sea-mammals are so dependent on hearing to communicate and feed, environmentalists and cetologists are concerned that they are being harmed by the increased ambient noise in the world's oceans caused by ships and marine seismic surveys.
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April, 2007
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The U.S. Navy Marine Mammal Program (NMMP) is a program administered by the U.S. Navy which studies the military use of marine mammals — principally Bottlenose Dolphins and California Sea Lions — and trains animals to perform tasks such as ship and harbor protection, mine detection and clearance, and equipment recovery. The program is based in San Diego, California, where animals are housed and trained on an ongoing basis. NMMP animal teams have been deployed for use in combat zones, such as during the Vietnam War and the Iraq War.
The program has been dogged by controversy over the treatment of the animals and speculation as to the nature of its mission and training. This has been due at least in part to the secrecy of the program, which was de-classified in the early 1990s. Since that time there have been ongoing animal welfare concerns, with many opposing the use of marine mammals in military applications, even in essentially non-combatant roles such as mine detection. The Navy cites external oversight, including ongoing monitoring, in defence of its animal care standards.
More on the U.S. Navy Marine Mammal Program
May, 2007
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Dolphin drive hunting, also called dolphin drive fishing, is a method of hunting dolphins and occasionally other small cetaceans by driving them together with boats and then usually into a bay or onto a beach. Their escape is prevented by closing off the route to the open sea or ocean with boats and nets. Dolphins are hunted this way in several places around the world. The largest number of dolphins are hunted using this method in Japan, however the practice also occurs on the Solomon Islands, the Faroe Islands and Peru. Dolphins are mostly hunted and killed for their meat; some are captured and end up in dolphinariums.
Despite the controversial nature of the hunt resulting in international criticism and the possible health risk that the often polluted meat causes, many thousands of dolphins are killed in drive hunts each year.
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June, 2007
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Whaling is the harvesting of free-roaming whales from the oceans and dates back to at least 6,000 BC. Whaling and other threats have led to at least 5 of the 13 great whales being listed as endangered. Commercial whaling is subject to a moratorium by the International Whaling Commission (IWC), however, at the 2006 IWC meeting, the St Kitts and Nevis Declaration, which protests the moratorium, was adopted by a slim majority.
It is unknown when humans began hunting whales. The earliest archaeological record of whaling is found in South Korea where carved drawings, dating back to 6,000 BC, show that Stone Age people hunted whales using boats and spears. However, over time, whaling techniques have grown more technologically sophisticated. Initially, whaling was confined to (near) coastal waters, such as the Basque fishery targeting the North Atlantic Right Whale from the 11th to 18th century and the Atlantic Arctic fishery around and in between Spitsbergen and Greenland from the 17th to the 20th century. However, after the emergence of modern whaling techniques, certain species of whale started to be seriously affected by whaling. These techniques were spurred in the 19th century by the increase in demand for whale oil, and later in the 20th century by a demand for whale meat.
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July, 2007
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The Blue Whale (Balaenoptera musculus) is a marine mammal belonging to the suborder of baleen whales. At up to 33 metres (110 ft) in length and 181 metric tonnes (200 short tons) or more in weight, it is believed to be the largest animal to have ever lived, though some fragmentary dinosaur discoveries such as the colossal Amphicoelias fragillimus may challenge this long-held belief.
Long and slender, the Blue Whale's body can be various shades of bluish-gray. There are at least three distinct subspecies: B. m. musculus of the north Atlantic and north Pacific, B. m. intermedia, of the Southern Ocean and B. m. brevicauda (also known as the Pygmy Blue Whale) found in the Indian 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 mainly of small crustaceans known as krill, as well as small fish and squid.
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August, 2007
[edit]Right whales are baleen whales belonging to the genus Eubalaena. Three right whale species are recognised in this genus. Sometimes the family Balaenidae is considered to be the family of right whales. Bowhead Whale, which has its own genus, Balaena also belongs to the Balaenidae family, and so is sometimes considered a right whale.
Right whales can grow up to 18 m (60 ft) long and weigh up to 100 tonnes. Their rotund bodies are mostly black, with distinctive callosities (roughened patches of skin) on their heads. They are called "right whales" because whalers thought the whales were the "right" ones to hunt, as they float when killed and often swim within sight of the shore. Populations were vastly reduced by intensive harvesting during the active years of the whaling industry. Today, instead of hunting them, people often watch these acrobatic whales for pleasure.
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