SANBI IDentifyIt - Species Blue Shark - Prionace glauca Family Prionace Geographic location / distribution Habitat: The blue shark a wide ranging oceanic shark found in tropical, subtropical and temperate waters. They prefer deep water and will occupy the area between the sea surface and up to 600m depths, in temperatures ranging from 12 C-20 C (can tolerate higher). Fishery Blue sharks are targeted in the pelagic shark longline fishery, and caught as bycatch in the tuna/swordfish longline fishery. Size limits Southern bluefin tuna >6.4kg Bigeye tuna >3.2kg Yellowfin tuna >3.2kg Swordfish >119cm LJFL / >18kg dressed Marlins >210cm LJFL Stock status Atlantic: Not over-exploited (stock assessment 2008) Indian: Not over-exploited (stock assessment 2008) Fisheries management Blue sharks fall within the management of the large pelagic fishery and are therefore managed by Regional Fisheries Management Organisations. South Africa is a member of ICCAT and a co-operating non-member of IOTC and CCSBT. Although RFMO's manage high seas fisheries, management recommendations and resolutions are implemented by South Africa through national legislation and permit conditions. The South African Shark fishery was actually banned at the end of 2009 but vessels are allowed to continue to fish on an exemption permit in 2010/2011. The Large Pelagic Fishery is composed of a tuna longline component, a tuna pole component, a swordfish targeting component and vessels operating under an exemption targeting pelagic shark and is managed by a Total Allowable Effort (TAE), meaning that instead of setting a limit on the catch, a limit is set on the number of rights holders allowed to catch tuna. Currently there is a limit of 200 rights holders in SA (including pole and longline). Longlining is not a very selective form of fishing and many species are caught incidentally on the the hooks. Bycatch species in this fishery include: billfishes (e.g. marlin), seabirds, turtles and sharks. Recent assessments show that eleven species of seabird, four species of turtle and 20 species of shark are caught incidentally by this fishery. The FAO estimates that approximately 28% of the catch is discarded. Local studies indicate that discards comprise approximately 22% of the catch. Bycatch restrictions therefore exist to protect vulnerable species like sharks: The bycatch of billfish cannot exceed 10% of the total tuna catch A precautionary catch limit of 25 seabirds has been set for tuna longline vessels, after which further management restrictions are enforced Shark fins need to be landed with their trunks, with the fins not exceeding 5% of the weight of the trunk on foreign vessels according to ICCAT and IOTC, but 8% on SA vessels. Any Bigeye, Swordfish or Southern Bluefin tuna landed must be accompanies by the relevant RFMO (ICCAT, IOTC or CCSBT) catch statistical document. Maturity and Sizes
On average, Blue sharks reach maturity after 5 years at a total length of roughly 218cm. Physical description Dorsal coloration dark blue, bright blue on sides and abruptly white on the undersides, usually slender body, long snout, large eyes, gill raker papillae, long, narrow, pointed pectoral fins, short labial furrows, first dorsal fin on back but closer to the pectoral bases than the pelvics, second dorsal less than a third size of first but about opposite it, a weak keel on the caudal peduncle, and a narrow-lobed caudal fin with a long ventral lobe. Identifying characters Long, narrow snout with long head Long, slender flabby body Very long, slender pectoral fins First dorsal fin closer to pelvic fins than pectoral fins Small gill slits Weak ridge on caudal peduncle Dorsal surfaced deep iridescent blue fading to blue with white ventral surfaces Other similar species Carcharhinus brachyurus - Bronze Whaler Carcharodon carcharias - Great White Shark Isurus oxyrinchus - Shortfin Mako Shark References FAO fact sheets http://www.fao.org/fishery/species/2498/en Fishery Resource Monitoring System Fact Sheets: http://firms.fao.org/firms/resource/9/en ICCAT Tuna fact sheets. ICAT Manual. January 2010. FAO. 2006-2010. Fisheries and Aquaculture Department. Biological characteristics of tuna/individual species sheets. FI Institutional Websites. Text by Michel Goujon and Jacek Majkowski. In: FAO Fisheries and Aquaculture Department[online]. Rome. Updated 24 February 2010. [Cited 30 November 2010]. Website: http://www.fao.org/fishery/topic/16082/en Blue shark. Mark Conlin/NMFS - Public Domain
Blue Shark Photo: Shane Anderson / U.S. NOAA Photographer: Shane Anderson / U.S. NOAA Copy right/website: Public Domain Blue Shark Photo: Mark Conlin / NMFS Photographer: Mark Conlin / NMFS - swfsc.noaa.gov Copyright/Website: Public Domain
Blue Shark Photo: Patrick Doll Photographer: Patrick Doll Copyright/Website: Patrick Doll / CC BY-SA 3.0 Blue Shark Photo: Patrick Doll Photographer: Patrick Doll Copyright/Website: Patrick Doll / CC BY-SA 3.0
Blue Shark Photo: Mark Conlin / NOAA Photographer: Mark Conlin / NOAA Copyright/Website: Public Domain Blue Shark Photo: Mark Conlin / NMFS Photographer: Mark Conlin / NMFS - swfsc.noaa.gov Copyright/Website: Public Domain
Blue Shark Photo: Shane Anderson / U.S. NOAA Photographer: Shane Anderson / U.S. NOAA Copy right/website: Public Domain Blue Shark Photo: Jos Antonio Gil Mart nez Photographer: Jos Antonio Gil Mart nez Copy right/website: Jos Antonio Gil Mart nez / CC BY 2.0 Blue Shark landed, headed and gutted without fins Photo: Nicola Okes Photographer: Nicola Okes Copy right/website: Nicola Okes / TRAFFIC
Blue Shark jaw Photo: Luca Oddone P hotographer: Luca Oddone Copy right/website: Luca Oddone / CC BY-SA 3.0 Blue Shark lower teeth Photo: D. Ross Robertson / Smithsonian Institute Photographer: P D. Ross Robertson / Smithsonian Institute Copy Copyright/Website: D. Ross Robertson / Smithsonian Institute - Public Domain
Blue Shark upper teeth Photo: D. Ross Robertson / Smithsonian Institute Photographer: P D. Ross Robertson / Smithsonian Institute Copyright/Website: D. Ross Robertson / Smithsonian Institute - Public Domain Blue Shark teeth Photo: Luca Oddone P hotographer: Luca Oddone Copy right/website: Luca Oddone / CC BY-SA 3.0
Blue Shark cartilage Photo: Michal Ma?as Photographer: P Michal Ma?as Copyright/Website: Michal Ma?as / CC BY 4.0 General Shark Identification Copyright/Website: TRAFFIC
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