{"id":2488,"date":"2016-05-10T14:43:04","date_gmt":"2016-05-10T18:43:04","guid":{"rendered":"http:\/\/pages.vassar.edu\/sensoryecology\/?p=2488"},"modified":"2016-05-10T14:43:04","modified_gmt":"2016-05-10T18:43:04","slug":"glow-in-the-dark-sharks-bioluminescence-of-catsharks-and-its-perception-of-conspecifics","status":"publish","type":"post","link":"https:\/\/pages.vassar.edu\/sensoryecology\/glow-in-the-dark-sharks-bioluminescence-of-catsharks-and-its-perception-of-conspecifics\/","title":{"rendered":"Glow In the Dark Sharks: Bioluminescence of Catsharks and its Perception of Conspecifics"},"content":{"rendered":"
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Catsharks are warm water dwelling sharks that tend to live near coral reefs\u00a0and along the\u00a0ocean floor, though some species prefer environments of greater depth. \u00a0They are smaller sharks and grow to be a\u00a0little over two feet long, and as their name suggests, their eyes have a\u00a0\u2018cat-like\u2019 appearance. \u00a0These sharks, along with other relatives, have been known to exhibit green\u00a0fluorescence.<\/div>\n
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Marine animals can fluoresce light at a specific depth threshold. \u00a0This is done by absorbing the abundant ambient blue light that penetrates the water and then reemitting that energy at a longer and lower energy wavelength. \u00a0This then produces colors that are perceived by humans as green, orange or red light. \u00a0As the depth increases, the amount of available light decreases and the type of light becomes restricted, and fluorescent light becomes more discrete. \u00a0Catshar<\/span>ks<\/span>\u00a0have specific visual pigmen<\/span>ts in their eyes that can detect fluorescent patterns against certain backgrounds.<\/span><\/div>\n
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Few studies have been done to investigate how this fluorescence appears to a shark’s conspecifics. \u00a0Researchers (Gruber et al. 2016)\u00a0examined two types of Catsharks, Cephaloscyllium ventriosum<\/em>, and Chain Catshark Scyliorhinus retifer<\/em>, whom occupy lower depths than other catsharks, and looked at their spectral sensitivity and visual characteristics, and how they perceived the fluorescent properties of their conspecifics in blue water.<\/div>\n
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They first conducted numerous skin analyses to determine what areas of the skin produced fluorescent emittance. \u00a0They found that fluorescence is emitted from both dark and light patches on skin, and that\u00a0lighter pigmented areas primarily produce a\u00a0green emission spectrum, while\u00a0darker patches produced a blue emission spectrum. \u00a0This finding suggests that there are either two compounds, or that same compound in two different chemical forms, that are responsible for the fluorescent properties.<\/div>\n
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To demonstrate the sharks’ perception of fluorescence in conspecifics, they performed hyper spectral imaging of the sharks\u2019 skin to\u00a0investigated how the green-dominated fluorescence affected their appearance in regards to\u00a0their environment. They also created\u00a0a \u00a0\u2018shark-eye\u2019 camera, that imitated the filters, spectral absorbance, and spectral sensitivity of the sharks, based on their monochromatic, slightly green shifted visual sensitivity.<\/p>\n
This <\/span>was done by fit<\/span>ting three lens filters o<\/span>n the<\/span>\u00a0c<\/span>amera while kee<\/span>pin<\/span>g <\/span>the blue channel\u00a0channel open. \u00a0<\/span>To imitate their environment, researchers calculated the dominant ambient light color and irradiance in the shallow depths, and recreated these settings in an aquarium. \u00a0They also investigated different light conditions;<\/div>\n
white ligh<\/span>t,<\/span>\u00a0nat<\/span>ura<\/span>l light, and specific wavelengths that would excite the fluorescent patches in the skin. \u00a0As can be seen from the images below, the patches are discrete to both human visual systems and the perceive shark visual system.<\/span><\/span><\/div>\n<\/div>\n
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The study aimed to investigate the properties of\u00a0Cephaloscyllium ventriosum<\/em>\u00a0and Scyliorhinus retifer<\/em>, how they fluoresce, and how tho fluorescence is\u00a0perceived by their conspecifics. \u00a0There is no indication as to what this\u00a0perceptions entail, and whether it is useful in mate detection, territorial claim, or general identification of conspecifics. \u00a0In the future, research should be done to investigate the behavioral components related to biofluorescence in Catsharks.<\/div>\n
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Gruber, David F., Loew, Ellis R., Deheyn, Demetri D., Akkaynak, Derya, Gaffney, Jean P., Smith, W. Leo, Davis, Matthew P., Stern, Jennifer H., Peiribone, Vincent A., Sparks, John S., “Biofluorescence in Catsharks (Scyliorhinidae): Fundamental Description and Relevance for Elasmobranch Visual Ecology.” Nature. 2016. Sci. Rep. 6(24751). doi: 10.1038\/srep2475.<\/div>\n
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“Sharkland: Catsharks.” PBS, 2008. \u00a0Web. \u00a0May 9, 2016.<\/div>\n
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Catsharks are warm water dwelling sharks that tend to live near coral reefs\u00a0and along the\u00a0ocean floor, though some species prefer environments of greater depth. \u00a0They are smaller sharks and grow to be a\u00a0little over two feet long, and as their … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":4917,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"gallery","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-2488","post","type-post","status-publish","format-gallery","hentry","category-uncategorized","post_format-post-format-gallery"],"_links":{"self":[{"href":"https:\/\/pages.vassar.edu\/sensoryecology\/wp-json\/wp\/v2\/posts\/2488","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pages.vassar.edu\/sensoryecology\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/pages.vassar.edu\/sensoryecology\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/pages.vassar.edu\/sensoryecology\/wp-json\/wp\/v2\/users\/4917"}],"replies":[{"embeddable":true,"href":"https:\/\/pages.vassar.edu\/sensoryecology\/wp-json\/wp\/v2\/comments?post=2488"}],"version-history":[{"count":2,"href":"https:\/\/pages.vassar.edu\/sensoryecology\/wp-json\/wp\/v2\/posts\/2488\/revisions"}],"predecessor-version":[{"id":2690,"href":"https:\/\/pages.vassar.edu\/sensoryecology\/wp-json\/wp\/v2\/posts\/2488\/revisions\/2690"}],"wp:attachment":[{"href":"https:\/\/pages.vassar.edu\/sensoryecology\/wp-json\/wp\/v2\/media?parent=2488"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/pages.vassar.edu\/sensoryecology\/wp-json\/wp\/v2\/categories?post=2488"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/pages.vassar.edu\/sensoryecology\/wp-json\/wp\/v2\/tags?post=2488"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}