Blue shark
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2008-07-16T08:30:26Z
Trollog
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/* Blue Sharks in Captivity */
{{Taxobox
| name = Blue shark
| fossil_range = [[Pliocene]] to Present<ref>{{cite journal
| last = Sepkoski
| first = Jack
| authorlink =
| coauthors =
| title = A compendium of fossil marine animal genera (Chondrichthyes entry)
| journal = Bulletins of American Paleontology
| volume = 364
| issue =
| pages = p.560
| publisher =
| location =
| date = 2002
| url = http://strata.ummp.lsa.umich.edu/jack/showgenera.php?taxon=575&rank=class
| doi =
| id =
| accessdate = 01/09/08 }}</ref>
| status = NT
| status_system = iucn3.1
| status_ref =<ref>{{cite press release |title=More oceanic sharks added to the IUCN Red List |publisher=[[IUCN]] |date=2007-02-22 |url=http://www.iucn.org/en/news/archive/2007/02/22_pr_sharks.htm |format= |language= |accessdate=2007-02-25 |quote= The blue shark, the world’s most abundant and heavily fished pelagic shark, stayed in the threat category ''Near hreatened''. }}</ref><ref>{{IUCN2006|assessors=Stevens|year=2000|id=39381|title=Prionace glauca|downloaded=11 May 2006}}</ref>
| image = blue shark.jpg
| image_width = 200px
| regnum = [[Animal]]ia
| phylum = [[Chordate|Chordata]]
| classis = [[Chondrichthyes]]
| subclassis = [[Elasmobranchii]]
| ordo = [[Carcharhiniformes]]
| familia = [[Carcharhinidae]]
| genus = '''''Prionace'''''
| genus_authority = Cantor, 1849
| species = '''''P. glauca'''''
| binomial = ''Prionace glauca''
| binomial_authority = ([[Carolus Linnaeus|Linnaeus]], [[1758]])
| range_map = Prionace_glauca_dis.png
| range_map_width = 240px
| range_map_caption = Range of blue shark
}}
{{Sharksportal}}
The '''blue shark''', ''Prionace glauca'', is a [[carcharhinid]] [[shark]] which is found in the deep waters of the world's [[temperate]] and [[tropical]] oceans. They prefer cooler waters and are not found, for example, in the [[Yellow Sea]] or in the [[Red Sea]]. Blue sharks are known to [[Fish migration|migrate]] long distances, from [[New England]] to [[South America]] for example. Although generally [[Lethargy|lethargic]], they are capable of moving very quickly if the need arises. Blue sharks are [[viviparous]] and are noted for their large litters of 25 to over 100 [[pup]]s. They feed primarily on small [[fish]] and [[squid]], although they are perfectly capable of taking larger prey should the opportunity present itself. Also, they may pose considerable danger to humans if they are encountered in large groups. They are often found in [[school]]s segregated by sex and size, and this behavior has led to their being nicknamed the "wolves of the sea". They are also the second fastest sharks, next to the [[Mako shark]].{{Fact|date=June 2008}}
==Distribution and habitat==
The blue shark is an oceanic and [[epipelagic zone|epipelagic]] shark found worldwide in deep [[temperate]] and [[tropical]] waters from the surface to about 350 meters.<ref name="fishbase">{{cite web|author=Ed. Ranier Froese and Daniel Pauly|title=Prionace glauca|publisher=FishBase|accessdaymonth=17 September |accessyear=2006|url=http://www.fishbase.org/Summary/SpeciesSummary.php?id=898}}</ref> In temperate seas it may come closer to shore where it can be observed by divers, while in tropical waters it occurs at greater depths. It is found from as far north as [[Norway]] to as far south as [[Chile]]. Blue sharks are found off the coasts of every continent, except for [[Antarctica]]. In the [[Pacific]] its greatest concentrations occur between 20° and 50° North but with strong seasonal fluctuations. In the tropics it is uniformly distributed between 20° N and 20° S. It prefers waters with a temperature range of 7 to 16°C but will tolerate temperatures of 21°C or above. It is highly migratory with records from the [[Atlantic]] showing a regular clockwise migration within the prevailing currents.<ref name="FAO">{{cite book|author= Leonard J. V. Compagno| title=Sharks of the World: An annotated and illustrated catalogue of shark species known to date|publisher=Food and Agriculture Organization of the United Nations|date=1984|pages=521-524, 555 – 61, 590}}</ref>
== Anatomy and appearance ==
[[Image:Prionace glauca.jpg|left|300px|thumb|Livery of ''Prionace glauca''.]]
Blue sharks are light-bodied with long [[pectoral fin]]s. The top of the body is deep blue, lighter on the sides, and the underside is white. The animal grows to 3.8 [[meter|m]] (12.5 [[foot (measurement)|ft]]) or more. The shark's typical weight is 136 [[kilogram|kg]] (300 [[pound (weight)|lb]]) to 182 kg (400 lb) and can grow to 205 kg (450 lb). The highest reported weight was 391 kg (861 lb).<ref>[http://homepage.mac.com/mollet/Pg/Pg_large.html large blue sharks<!-- Bot generated title -->]</ref> They are rarely confused with other sharks.
==Ecology==
[[Squid]] are an important prey item for blue sharks, but their diet also comprises other invertebrates such as [[cuttlefish]] and pelagic [[octopus]]es, as well as [[lobster]], [[shrimp]], [[crab]], a large number of bony fishes, small sharks, mammalian carrion and occasional sea birds. Whale and porpoise [[blubber]] and meat have been retrieved from the stomachs of captured specimens and they are known take [[cod]] from trawl nets.<ref name="FAO" /> Apparently, blue sharks do not or only very rarely eat [[tuna]]{{Fact|date=May 2007}}.
Adult blue sharks do not suffer [[predation]] on a regular basis, except by humans. Young and smaller individuals may get eaten by any sufficiently large carnivore. However, they are host to several species of [[parasite]]s. For example, the blue shark is the [[definite host]] of the [[tetraphyllidea]]n [[tapeworm]], ''[[Pelichnibothrium speciosum]]'' (=''Prionacestus bipartitus''). They become infected by eating the intermediate hosts, probably [[Opah]], ''Lampris guttatus'', and/or [[longnose lancetfish]], ''Alepisaurus ferox'' <small>(Scholz ''et al.'' 1998)</small>.
==Reproduction==
[[Image:Blueshark 300.jpg|thumb|right|200px|Back of blue shark]]They are vivaporous, with a yolk-sac placenta, delivering 4 to 135 pups per litter. The gestation period is between 9 and 12 months. Females mature at 5 to 6 years of age and males at 4 to 5. Courtship is believed to involve biting by the male, as mature specimens can be accurately sexed according to the presence or absence of bite scarring. Female blue sharks have adapted to the rigours of the mating ritual by developing skin 3 times as thick as that of males.<ref name="FAO" />
==Relationship to Humans==
Blue sharks are the most heavily fished sharks in the world mainly as result of by-catch. It is estimated that 10 to 20 million individuals are killed each year as a result of fishing. The flesh is edible, but not widely sought after; it is utilized fresh, dried, smoked and salted and for [[fishmeal]]. The skin is used for [[leather]], the fins for [[shark-fin soup]] and the liver for oil.<ref name="FAO" /> Blue sharks are occasionally sought as [[game fish]] and they are frequent accidental catches by commercial fisherman seeking [[swordfish]] or [[tuna]].
Conversely, Blue Sharks rarely attack humans. While they are one of the 20 or so species of shark considered dangerous they rate on the low end of that spectrum. Most interaction between blue sharks and humans takes place in deep water as they rarely venture close to shore. As of 2008, there are only 4 records of Blue Shark related human fatalities.
<ref>[http://www.flmnh.ufl.edu/fish/sharks/Statistics/species2.htm ISAF Statistics on Attacking Species of Shark<!-- Bot generated title -->]</ref>
==Blue Sharks in Captivity==
Blue Sharks, like most open ocean sharks, tend to fare poorly in captivity. Attempts at doing so using circular tanks with long glide paths, and pools with 10’ central depth gently ascending to zero depth have met with mixed results at best; most specimens last less than 30 days. As with other pelagic sharks, the animals seem to have trouble avoiding walls or any other obstacles. In one case at Sea World San Diego, the Blue did fairly well until [[Bull Shark]]s were added to the tank; the Bulls subsequently ate the Blues. The current captive record for Blue Sharks (as of 2008) is held by The New Jersey Aquarium for a specimen that lasted roughly 7 months in captivity before expiring of an apparent bacterial infection. <ref>[http://homepage.mac.com/mollet/Pg/Pg_captive.html Blue Shark (Prionace glauca) in Captivity<!-- Bot generated title -->]</ref>
==See also==
* [[List of sharks]]
==References==
{{wikispecies|Prionace glauca}}
<references/>
* {{FishBase_species|genus=Prionace|species=glauca |year=2005|month=09}}
* {{ITIS|ID=160424 |taxon=Prionace glauca|year=2005|date=15 November}}
* {{marinebio|id=35|name=Blue shark, Prionace glauca}}
* {{eol|17050972|Blue shark, Prionace glauca}}
* Scholz, Tomáš; Euzet, Louis & Moravec, František (1998): Taxonomic status of ''Pelichnibothrium speciosum'' Monticelli, 1889 (Cestoda: Tetraphyllidea), a mysterious parasite of ''Alepisaurus ferox'' Lowe (Teleostei: Alepisauridae) and ''Prionace glauca'' (L.) (Euselachii: Carcharinidae). ''Systematic Parasitology'' '''41'''(1): 1 – 8. <small>{{doi|10.1023/A:1006091102174}}</small> (HTML abstract)
==External links==
{{commons|Prionace glauca|Blue shark}}
* ARKive - [http://www.arkive.org/species/GES/fish/Prionace_glauca/ Images and movies of the blue shark ''(Prionace glauca)'']
* [http://www.marinebiodiversity.ca/shark/english/blue.htm Canadian Shark research laboratory]
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[[Category:Carcharhinidae]]
[[Category:Viviparous fish]]
[[ca:Tintorera (tauró)]]
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[[de:Blauhai]]
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[[es:Prionace glauca]]
[[fr:Requin bleu]]
[[ga:Siorc gorm]]
[[ko:청새리상어]]
[[it:Prionace glauca]]
[[lt:Melsvasis ryklys]]
[[nl:Grote blauwe haai]]
[[ja:ヨシキリザメ]]
[[no:Blåhai]]
[[pt:Tubarão-azul]]
[[sc:Canísca]]
[[fi:Sinihai]]
[[sv:Blåhaj]]
[[zh:大青鲨]]