The Blue Shark (Prionace glauca) plays a crucial role in its ecosystem. It occurs as transboundary stocks, and is distributed circumglobally in tropical, subtropical, and warm-temperate waters, both on the high seas and within EEZs, from 60˚N to 50˚S latitudes. Juvenile, sub-adult and adult Blue Sharks all migrate, generally segregated by sex and age. Blue Shark migration patterns are linked to reproductive cycles, with mature individuals moving across country borders.

The Blue Shark is viviparous, with a gestation period between 9-12 months and litter size ranging from 1-68 pups (average 34). Reproductive characteristics differ between oceans, but in general males mature between 4-6 years and females between 5-7 years, with the maximum age being 20 years. Primarily feeding on pelagic fishes and squids, the Blue Shark is a high trophic level predator. Its trophic level is 4.1 according to Cortés, which is higher than average for shark species.

As one of the most wide-ranging of the highly migratory shark species, Blue Sharks interact with fisheries that use a variety of gear types. However, they are vulnerable to fishing pressure, both through targeted fisheries and as bycatch. With limited intergovernmental and domestic action globally to limit catches to sustainable levels, unregulated fishing pressure is the primary threat to them globally. Global capture production has increased from 4 to 14 per cent from 1998–2011. Additionally, Blue Shark fins remain the most heavily traded of all species in the Hong Kong fin trade.

Due to significant declines in its populations to below historic levels, the Blue Shark is listed on the IUCN Red List of Threatened Species as Near Threatened globally and in European waters, and Critically Endangered in the Mediterranean. Governments around the world are encouraged to act to conserve this iconic species by taking precautionary, regionally coordinated action to ensure that Blue Shark fisheries are sustainable throughout the shark’s migratory range. Currently, the Blue Shark is also listed in Appendix II of CMS.