Gray whale: Difference between revisions
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==External links== |
==External links== |
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*[http://www.nmfs.noaa.gov/pr/species/mammals/cetaceans/graywhale.htm US National Marine Fisheries Service Gray Whale web page] |
*[http://www.nmfs.noaa.gov/pr/species/mammals/cetaceans/graywhale.htm US National Marine Fisheries Service Gray Whale web page] |
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*{{IUCNlink|8099|IUCN Redlist listing for Gray Whale}} |
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*[http://www.arkive.org/gray-whale/eschrichtius-robustus/ Arkive - images & video of Gray Whale] |
*[http://www.arkive.org/gray-whale/eschrichtius-robustus/ Arkive - images & video of Gray Whale] |
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*[http://www.panda.org/what_we_do/endangered_species/endangered_species_list/cetaceans/about/gray_whale222/ World Wide Fund for Nature (WWF) - species profile for Gray Whale] |
*[http://www.panda.org/what_we_do/endangered_species/endangered_species_list/cetaceans/about/gray_whale222/ World Wide Fund for Nature (WWF) - species profile for Gray Whale] |
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Revision as of 20:55, 21 November 2009
| Gray Whale[1] Temporal range: Upper Pleistocene - Recent
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| A Gray Whale spy-hopping | |
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| Size comparison against an average human | |
| Scientific classification | |
| Kingdom: | |
| Phylum: | |
| Class: | |
| Order: | |
| Suborder: | |
| Family: | Eschrichtiidae Ellerman & Morrison-Scott, 1951
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| Genus: | Eschrichtius
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| Species: | E. robustus
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| Binomial name | |
| Eschrichtius robustus Lilljeborg, 1861
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| Gray Whale range | |
The Gray (or Grey) Whale (Eschrichtius robustus) is a baleen whale that travels between feeding and breeding grounds yearly. It reaches a length of about 16 meters (52 ft), 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. The Gray Whale is the sole species in the genus Eschrichtius, which in turn is the sole genus in the family Eschrichtiidae. This animal is descended from the filter-feeding whales that developed at the beginning of the Oligocene, over 30 million years before the present.
The Gray Whale is distributed in an eastern North Pacific (American) population and a critically endangered western North Pacific (Asian) population. Eastern and western populations in the North Atlantic became extinct in the 18th century.
Systematics and taxonomy
The Gray Whale has been traditionally placed in its own monotypic genus and family, however recent DNA sequencing analysis indicates that certain rorquals of the family Balaenopteridae, such as the Humpback Whale (Megaptera novaeangliae) and Fin Whale (Balaenoptera physalus) are more closely related to the Gray Whale than they are to some other rorquals, such as the minke whales.[3][4] It was placed in its own genus by John Gray in 1865, naming it in honour of zoologist Daniel Eschricht.[5] It is an irony that the subfossil remains of now extinct gray whales from the Atlantic coasts of England and Sweden were used by Gray to make the first scientific description of a species then surviving only in Pacific waters. The living Pacific species was described by Cope as Ranchianectes glaucus in 1869.[6] Skeletal comparisons showed the Pacific species to be identical to the Atlantic remains in the 1930s and Gray's name has been generally accepted since.[7][8] Although identity between the Atlantic and Pacific populations cannot be proven by anatomical data, the skeleton of the gray whale is distinctive and easy to distinguish from that of all other living whales.[9] Molecular analysis of Atlantic gray whale subfossil remains are needed to confirm the skeletal evidence of identity with the Pacific population.
The name Eschrichtius gibbosus is sometimes seen; this is dependent on the acceptance of a 1777 description by Erxleben.[10]
Many other names have been ascribed to the Gray Whale, including Desert Whale,[11] Devil Fish, Gray Back, Mussel Digger and Rip Sack.[12]
Description
The Gray Whale is a dark slate-gray in color and covered by characteristic gray-white patterns, scars left by parasites which drop off in the cold feeding grounds. Individual whales are typically identified using photographs of their dorsal surface and matching the scars and patches associated with parasites that have fallen off the whale or are still attached.
Gray Whales measure from 16 ft (4.9 m) long for newborns to 45 ft (14 m) long for adult females (which tend to be slightly larger than adult males.) Newborns are a darker gray to black in color. On maturity, a gray whale can reach a maximum weight of 40 tons.
They have two nostrils on top of their head, which can create a distinctive V-shaped blow at the surface in calm wind conditions.
While it possesses similar characteristics to many of the baleen whales, there are some notable features that distinguish the gray whale from other Mysticetes. The baleen of gray whales is variously described as cream, off-white, or blond in color, and unusually short compared to that of other baleen whales. Small depressions on the upper jaw contain a lone stiff hair each, but can only be seen on close inspection. On the ventral surface of the head, it lacks the numerous prominent furrows of the related rorquals, instead bearing two to five shallow furrows on the underside of the throat. The Gray Whale also lacks a dorsal fin, instead bearing several dorsal 'knuckles,' which are 6 to 12 raised bumps on the midline of the rear quarter of the animal, leading to the fluke or tail. The tail itself is 10–12 ft (3.7 m) across and deeply notched at the center while tapering at the edges to a point.
Whale population
Two Pacific Ocean populations of the Gray Whale are known to exist: one of not more than 160 individuals whose migratory route is unknown, but presumed to be between the Sea of Okhotsk and southern Korea, and a larger one with a population between 20,000 and 22,000 individuals in the Eastern Pacific travelling between the waters off Alaska and Baja California. In 2007, S. Elizabeth Alter used a genetic approach to estimate prewhaling abundance based on samples from 42 California Gray Whales and reported DNA variability at 10 genetic loci consistent with a population size of 76,000–118,000 individuals, approximately three to five times more numerous than today’s average census size.[13]
The Gray Whale was thought to have become extinct in the North Atlantic in the 18th century.[14] Radiocarbon dating of subfossil or fossil European (Belgium, Netherlands, Sweden, United Kingdom) coastal remains has confirmed this, with whaling the possible cause.[15] Similarly, radiocarbon dating of American east coastal remains confirm Gray Whales existed at least through the 17th century. The western Atlantic population ranged at least from Southampton, NY to Jupiter Island, FL based on discoveries of skeletal remains.[8]
In the fall, the Eastern Pacific, or California, Gray Whale starts a 2–3 month, 8,000–11,000 km trip south along the west coast of Canada, the United States and Mexico. The animals travel in small groups. The destinations of the whales are the coastal waters of Baja California and the southern Gulf of California, where they breed and the young are born. The breeding behavior is complex and often involves three or more animals. The gestation period is about one year, and females have calves every other year. The calf is born tail first and measures about 4 meters in length. It is believed that the shallow waters in the lagoons there protect the newborn from sharks.
After several weeks, the return trip starts. This round trip of 16,000–22,000 km, at an average speed of 5 km/h, is believed to be the longest yearly migration of any mammal. A whale watching industry provides ecotourists and marine mammal enthusiasts the opportunity to see groups of Gray Whales as they pass by on their migration.
Feeding
The whale feeds mainly on benthic crustaceans which it eats by turning on its side (usually the right) and scooping up the sediments from the sea floor. It is classified as a baleen whale and has a baleen, or whalebone, which acts like a sieve to capture small sea animals including amphipods taken in along with sand, water and other material. Mostly, the animal feeds in the northern waters during the summer; and opportunistically feeds during its migration trip, depending primarily on its extensive fat reserves.
Migration
The migration route of the Eastern Pacific, or California, Gray Whale is often described as the longest known mammal migration. Beginning in the Bering and Chukchi seas and ending in the warm-water lagoons of Mexico's Baja peninsula, their round trip journey moves them through 12,500 miles of coastline.
This journey begins each October as the northern ice pushes southward. Travelling both night and day, the Gray Whale averages approximately 120 km (80 miles) per day. By mid-December to early January, the majority of the Gray Whales are usually found between Monterey and San Diego, where they are often seen from shore.
By late December to early January, the first of the Gray Whales begin to arrive the calving lagoons of Baja. These first whales to arrive are usually pregnant mothers that look for the protection of the lagoons to give birth to their calves, along with single females seeking out male companions in order to mate. By mid-February to mid-March the bulk of the Gray Whales have arrived the lagoons. It is at this time that the lagoons are filled to capacity with nursing, calving and mating Gray Whales.
By late March or early April a number of Gray Whales enter Puget Sound and may be seen from Canada as far south as Everett, Washington near the mouth of the Snohomish River.
The three primary lagoons that the whales seek in Baja California are Laguna Ojo de Libre (formerly known in English as Scammon Lagoon after whaleman Charles Scammon who discovered the lagoons in the 1850s and hunted the Grays,[16][17]), San Ignacio, and Magdalena. As noted, the Grays were called the devil fish until the the Spring of 1972 when a fisherman in the Laguna San Ignacio named Francisco "Pachico" Mayoral (although terrified to death) reached out and placed his hand in the water as a Gray mother approached his fishing boat and gently "rubbed up against him".[18] Today the whales in all three lagoons are protected, but whale watching in the lagoons is permitted.
Throughout February and March, the first Gray Whales to leave the lagoons are the males and single females. Once they have mated, they will begin the trek back north to their summer feeding grounds in the Bering and Chukchi seas. Pregnant females and nursing mothers with their newborn calves are the last to leave the lagoons. They leave only when their calves are ready for the journey, which is usually from late March to mid-April. Often there are still a few lingering Gray Whale mothers with their young calves in the lagoons well into May.
A population of about 2,000 Gray Whales stay along the Oregon coast throughout the summer, not making the farther trip to Alaska waters.
Conservation and human interaction
The only predators of adult Gray Whales are humans and the Orca. Beginning in the 1570s the Japanese began to catch Gray Whales. At Kawajiri, Nagato 169 Gray Whales were caught between 1698 and 1889, or a little over one a year. At Tsuro, Shikoku 201 were taken between 1849 and 1896. Several hundred more were probably caught by European (primarily American) whalemen in the Sea of Okhotsk from the 1840s to perhaps the early 20th century. A total of forty-four were caught by net whalemen in Japan during the 1890s. The real damage was done between 1911 and 1933, when Korean and Japanese whalemen killed 1,449 Gray Whales. By 1934 the western Gray Whale was near extinction. From 1891 to 1966 an estimated 1,800-2,000 Gray Whales were caught, with peak catches of 100-200 annually occurring in the 1910s.
European commercial whaling for Gray Whales in the North Pacific began in the winter of 1845-46, when two United States ships, the Hibernia and the United States, caught thirty-two in Magdalena Bay. More ships followed in the two following winters (1846-47 and 1847-48), after which gray whaling in the bay was nearly abandoned because "of the inferior quality and low price of the dark-colored gray whale oil, the low quality and quantity of whalebone from the gray, and the dangers of lagoon whaling."
Gray whaling in Magdalena Bay was revived in the winter of 1855-56 by several vessels, mainly from San Francisco, including the ship Leonore, under Captain Charles Melville Scammon. This was the first of eleven winters from 1855 through 1865 known as the "bonanza period," during which gray whaling along the coast of Baja California reached its peak. Not only were Grays taken in Magdalena Bay, but also by ships anchored along the coast from San Diego south to Cabo San Lucas and from whaling stations from Crescent City in northern California south to San Ignacio Lagoon. During the same period vessels targeting Right and Bowhead Whales in the Gulf of Alaska, Sea of Okhotsk, and the Western Arctic would occasionally take a Gray or two if neither of the former two species were in sight.
In December 1857 Charles Scammon, in the brig Boston, along with his schooner-tender Marin, entered Laguna Ojo de Liebre (Jack-Rabbit Spring Lagoon) or later known as Scammon's Lagoon (by 1860) and found one of the Gray Whale's last refuges. In three months he caught a total of forty-seven whales for a yield of 1,700 barrels of oil. In the winter of 1859-60 Scammon, in the bark Ocean Bird, along with several other vessels, performed a similar feat of daring by entering San Ignacio Lagoon to the south where he discovered the last of the Gray Whales' breeding lagoons. Within only a couple of seasons the lagoon was nearly cleaned out of whales.
Between 1846 and 1874 an estimated 8,000 Gray Whales were killed by European whalemen, with over half having been killed in the Magdalena Bay complex (Estero Santo Domingo, Magdalena Bay itself, and Almejas Bay) and by shore whalemen in California and Baja California. This, for the most part, does not take into account the large number of calves injured or left to starve after their mothers had been killed in the breeding lagoons. Since whalemen primarily targeted mothers with calves in the lagoons, several thousand should probably be added to the total. Also, shore whaling in California and Baja California continued after this period, until the early 20th century.
During the modern era a second, shorter, and less intensive hunt occurred for Gray Whales in the eastern North Pacific. Only a few were caught from two whaling stations on the coast of California from 1919 to 1926, and a single station in Washington (1911-21) accounted for the capture of another. For the entire west coast of North America for the years 1919 to 1929 some 234 Gray Whales were caught. Only a dozen or so were taken by the stations in British Columbia, nearly all of them in the 1953 season at Coal Harbor. A whaling station in Richmond, California caught 311 Gray Whales for "scientific purposes" between 1964 and 1969. From 1961 to 1972 the Soviet Union caught 138 Gray Whales, although they originally had reported not having taken any. The only other significant catch was made in two seasons by the steam-schooner California off Malibu, California. In the winters of 1934-35 and 1935-36 the California anchored off Point Dume in Paradise Cove. In all she caught at least 272 Gray Whales, with 186 of them being caught in the first winter. In 1936 Gray Whales were protected, forcing the ship to concentrate on other species.
Gray Whales have been granted protection from commercial hunting by the International Whaling Commission (IWC) since 1949, and are no longer hunted on a large scale.
Limited hunting of Gray Whales has continued since that time, however, primarily in the Chukotka region of north-eastern Russia, where large numbers of Gray Whales spend the summer months. This hunt has been allowed under an "aboriginal/subsistence whaling" exception to the commercial-hunting ban. Anti-whaling groups have protested the hunt, saying that the meat from the whales is not for traditional native consumption, but is used instead to feed animals in government-run fur farms; they cite annual catch numbers that rose dramatically during the 1940s, at the time when state-run fur farms were being established in the region. Although the Soviet government denied these charges as recently as 1987, in recent years the Russian government has acknowledged the feeding of Gray Whale meat to animals on fur farms in the region. The Russian IWC delegation has said that the hunt is justified under the aboriginal/subsistence exemption, since the fur farms provide a necessary economic base for the region's native population.
Currently, the annual quota for the Gray Whale catch in the region is 140 whales per year. Pursuant to an agreement between the United States and Russia, the Makah Indian tribe of Washington claimed 4 whales per year from the total IWC quota established at the 1997 meeting. With the exception of a single Gray Whale killed in 1999, the Makah people have been prevented from conducting Gray Whale hunts by a series of legal challenges, culminating in a United States federal appeals court decision in December 2002 that said the National Marine Fisheries Service must prepare an Environmental Impact Statement before allowing the hunt to go forward. On September 8, 2007, five members of the Makah tribe shot a gray whale using high powered rifles in spite of the limitations. The whale died within 12 hours, sinking while heading out to sea.[19]
As of 2001, the population of California Gray Whales had grown back to about 26,000 animals. As of 2004, the population of Western Pacific (seas near Korea, Japan, and Kamchatka) Gray Whales was an estimated 101 individuals.
The North Atlantic population of Gray Whales may have been hunted to extinction in the 18th century. There is circumstantial evidence that whaling could have possibly contributed to this population's decline, as an increase in whaling activity in the 17th and 18th century did coincide with the population's disappearance.[8] A. B. Van Deinse points out that the "scrag whale", described by P. Dudley in 1725 as one of the species hunted by the early New England whalers, was almost certainly the Gray Whale.[20][21] In his 1835 history of Nantucket Island, Obed Macy wrote that in the early pre-1672 colony a whale of the kind called "scragg" entered the harbor and was pursued and killed by the settlers.[22] This event started the Nantucket whaling industry.
As of 2008, the IUCN regards the Gray Whale as being of "Least Concern" from a conservation perspective. However, the specific subpopulation in the northwest Pacific is regarded as being "Critically Endangered".[2] The northwest Pacific population is also listed as endangered by the U.S. Government National Marine Fisheries Service under the U.S. Endangered Species Act.
Captivity
In 1972, a 3-month-old Gray Whale named Gigi was captured for brief study by Dr. David W. Kenney, and then released near San Diego.
In January 1997, the new-born baby whale J.J. was found helpless near the coast of Los Angeles, California, 4.2 m long and 800 kg in mass. Nursed back to health in SeaWorld San Diego, she was released into the Pacific Ocean on March 31, 1998, 9 m long and 8500 kg in mass. She shed her radio transmitter packs three days later.
References
- ^ Mead, J. G.; Brownell, R. L. Jr. (2005). "Order Cetacea". In Wilson, D. E.; Reeder, D. M. (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. pp. 723–743. ISBN 978-0-8018-8221-0. OCLC 62265494.
- ^ a b Template:IUCN2008
- ^ Arnason, U., Gullberg A. & Widegren, B. (1993). "Cetacean mitochondrial DNA control region: sequences of all extant baleen whales and two sperm whale species". Molecular Biology and Evolution. 10 (5): 960–970. PMID 8412655. Retrieved 2009-01-25.
{{cite journal}}: Unknown parameter|day=ignored (help); Unknown parameter|month=ignored (help)CS1 maint: multiple names: authors list (link) - ^ Sasaki, T.; et al. (February 23, 2005). "Mitochondrial Phylogenetics and Evolution of Mysticete Whales". Systematic Biology. 54 (1): 77–90. doi:10.1080/10635150590905939. Retrieved 2009-01-25.
{{cite journal}}: Explicit use of et al. in:|author=(help)CS1 maint: date and year (link) - ^ Gray (1864). "Eschrichtius". Ann. Mag. Nat. Hist. 3 (14): 350.
- ^ Cope (1869). "Rhachianectes". Proc. Acad. Nat. Sci. Philadelphia. 21: 15.
- ^ Cederlund, BA (1938). "A subfossil gray whale discovered in Sweden in 1859". Zoologiska Bidrag Fran Uppsala. 18: 269–286.
- ^ a b c Mead JG, Mitchell ED (1984). "Atlantic gray whales". In Jones ML, Swartz SL, Leatherwood S (ed.). The Gray Whale. London: Academic Press. pp. 33–53.
{{cite book}}: CS1 maint: multiple names: editors list (link) - ^ Bryant, PJ (1995). "Dating Remains of Gray Whales from the Eastern North Atlantic". Journal of Mammalogy. 76 (3): 857–861.
- ^ Erxleben (1777). "Balaena gibbosa". Systema regni animalis: 610.
- ^ Katherine Waser Ecotourism and the desert whale: An interview with Dr. Emily Young (1998). Arid Lands Newsletter.
{{cite journal}}: Missing or empty|title=(help) - ^ "Eschrichtius robustus". Integrated Taxonomic Information System. March 18.
{{cite web}}: Check date values in:|date=and|year=/|date=mismatch (help) - ^ Alter, SE (2007). "DNA evidence for historic population size and past ecosystem impacts of gray whales". Proceedings of the National Academy of Sciences. 104 (38): 15162–15167. doi:10.1073/pnas.0706056104.
{{cite journal}}: Unknown parameter|month=ignored (help) - ^ Rice DW (1998). Marine Mammals of the World. Systematics and Distribution. Special Publication Number 4. Lawrence, Kansas: The Society for Marine Mamalogy.
{{cite book}}: Cite has empty unknown parameter:|chapterurl=(help) - ^ Bryant, PJ (1995). "Dating Remains of Gray Whales from the Eastern North Atlantic". Journal of Mammalogy. 76 (3): 857–861. doi:10.2307/1382754.
{{cite journal}}: Unknown parameter|month=ignored (help) - ^ Davis, T.N. (September 6, 1979). "Recovery of the Gray Whale". Alaska Science Forum. Retrieved 2009-01-25.
{{cite web}}: CS1 maint: date and year (link) - ^ Niemann, G. (2002). Baja Legends. Sunbelt Publications. pp. 171–173. ISBN 0932653472.
- ^ Russell,Dick (2004). Eye of the Whale: Epic Passage From Baja To Siberia. Island Press. pp. 48–49. ISBN 1559630884.
- ^ Local News | Gray whale shot, killed in rogue tribal hunt | Seattle Times Newspaper
- ^ Van Deinse, AB (1937). "Recent and older finds of the gray whale in the Atlantic". Temminckia. 2: 161–188.
- ^ Dudley, P (1725). "An essay upon the natural history of whales". Philosophical Transactions of the Royal Society of London. 33: 256–259.
- ^ Macy O (1835). The History of Nantucket:being a compendious account of the first settlement of the island by the English:together with the rise and progress of the whale fishery, and other historical facts relative to said island and its inhabitants:in two parts. Boston: Hilliard, Gray & Co. ISBN 1437402232.