{"id":3046,"date":"2016-02-10T23:31:55","date_gmt":"2016-02-10T23:31:55","guid":{"rendered":"http:\/\/colinmunrophotography.com\/blog\/?p=3046"},"modified":"2017-04-02T21:12:02","modified_gmt":"2017-04-02T20:12:02","slug":"blue-sharks-graceful-sea-wolves","status":"publish","type":"post","link":"https:\/\/colinmunrophotography.com\/blog\/blue-sharks-graceful-sea-wolves\/","title":{"rendered":"Blue sharks, graceful sea wolves"},"content":{"rendered":"

The blue shark, Prionace glauca<\/i>, is possibly the most beautiful of sharks.\u00a0 It is a slender, fast and graceful shark, but it is the vivid, almost electric blue colouration that is most striking.<\/p>\n

\"Blue<\/a>

A blue shark passes close by.<\/p><\/div>\n

Blues are oceanic sharks, uncommon in shallow coastal waters.\u00a0 In the tropics they are normally found in deeper, cooler waters, but in temperate seas they are more likely to be found in surface waters (thus are described as being epipelagic).\u00a0 This does not mean that in temperate waters they occur only in the warmer surface layers.\u00a0 Recent data from satellite tags have shown that they blues may regularly undertake dives to more than 1000 metres.\u00a0 One male blue shark, nicknamed Bodi by the researchers, was logged as having dived to 1250 metres off the Bay of Plenty (New Zealand) three weeks after being tagged in 2013.\u00a0 An earlier joint British- Portuguese study recorded a female blue shark diving to 1160 metres off the coast of Portugal (Queiroz et al<\/em>, 2012). \u00a0 This behaviour is probably linked to hunting activity.\u00a0 Blue sharks are quite catholic in their diet, eating a wide range of mid-water fish and cephalopods,\u00a0 but appear to be particularly fond of squid, and of course squid will often undertake marked vertical migrations, with many species occurring at considerable depth.\u00a0 That this deep diving behaviour of blues is primarily foraging for food is supported by a preponderance of deep water quid species found in the gut of contents of blue sharks caught by long-lines, in particular the wonderfully named vampire squid, Vampyroteuthis infernalis<\/em>, a small deep-water squid those scientific name literally translates as the vampire squid from hell<\/em>.<\/p>\n

In the northern Atlantic at least, they appear to undertake seasonal migrations. They are unusual amongst ocean sharks in that they will sometimes aggregate in groups, often all same sex, as they roam.\u00a0 This pack-like activity has lead to them being dubbed the\u00a0wolves of the se<\/em>a.\u00a0 Around Southwest Britain blue sharks start to appear in June each year, and hang around until late October or early November.\u00a0 Although there have been attacks on humans by blue sharks, aggressive behaviour is relatively rare.\u00a0 Certainly in British waters, where large blues are rarely seen, most are quite timid and easy to scare off accidentally.\u00a0 The largest blue caught in UK waters was approximately 2.5 metres long and weighed 107kg. This was caught off Penzance, Cornwall, in 2012 (but was also released).\u00a0 Blues can grow up to 3.5 metres or more (the largest on record was 3.83 metres long) the females being significantly larger than males.<\/p>\n

\"Blue<\/a>

Blue shark, Prionace glauca. A female blue shark swimming close to the surface off Southwest Cornwall, UK.<\/p><\/div>\n

An underwater encounter with a blue shark is a wonderful experience, and provided one takes sensible precautions (i.e. wearing gloves, not wearing shiny bits of equipment and NOT<\/span> trying to feed them) is normally quite safe.\u00a0 Blue sharks have been one the shark species hardest hit by the practice of shark fining in various parts of the World and there numbers appear to have declined markedly.\u00a0 Consequently it’s worth remembering that most blue sharks have far more cause to fear us that vice versa.<\/p>\n

The above, and more of my blue shark images, can be found on my stock image website www.colinmunroimages.com<\/a>. They can be licensed for publication, or purchased as fine art prints and canvas wall art.<\/p>\n

If you enjoyed this post why not subscribe to my blog (see box on right) and like my facebook page<\/a> .<\/p>\n

 <\/p>\n

References cited: Queiroz N, Humphries NE, Noble LR, Santos AM, Sims DW (2012) Spatial Dynamics and Expanded Vertical Niche of Blue Sharks in Oceanographic Fronts Reveal Habitat Targets for Conservation. PLoS ONE 7(2): e32374. doi:10.1371\/journal.pone.0032374<\/p>\n

 <\/p>\n","protected":false},"excerpt":{"rendered":"

The blue shark, Prionace glauca, is possible the most beautiful of sharks. It is a slender, fast and graceful shark, but it is the vivid, almost electric blue colouration that is most striking.<\/p>\n","protected":false},"author":1,"featured_media":2521,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[92,167],"tags":[973,751,755,759,975,143,758,976,757,974],"class_list":["post-3046","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-marine-life","category-sharks-marine-life","tag-atlantic-sharks","tag-blue-shark","tag-blue-shark-pictures","tag-blue-sharks-off-cornwall","tag-colin-munro-images","tag-colin-munro-photography","tag-images-of-blue-sharks","tag-marine-stock-photography","tag-prionace-glauca","tag-shark"],"_links":{"self":[{"href":"https:\/\/colinmunrophotography.com\/blog\/wp-json\/wp\/v2\/posts\/3046","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/colinmunrophotography.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/colinmunrophotography.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/colinmunrophotography.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/colinmunrophotography.com\/blog\/wp-json\/wp\/v2\/comments?post=3046"}],"version-history":[{"count":14,"href":"https:\/\/colinmunrophotography.com\/blog\/wp-json\/wp\/v2\/posts\/3046\/revisions"}],"predecessor-version":[{"id":3245,"href":"https:\/\/colinmunrophotography.com\/blog\/wp-json\/wp\/v2\/posts\/3046\/revisions\/3245"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/colinmunrophotography.com\/blog\/wp-json\/wp\/v2\/media\/2521"}],"wp:attachment":[{"href":"https:\/\/colinmunrophotography.com\/blog\/wp-json\/wp\/v2\/media?parent=3046"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/colinmunrophotography.com\/blog\/wp-json\/wp\/v2\/categories?post=3046"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/colinmunrophotography.com\/blog\/wp-json\/wp\/v2\/tags?post=3046"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}