The demand for shark’s fin soup in Asia is very likely the reason for a steep decline in the population of blue sharks (Prionace glauca) off the coasts of the UK and in the Atlantic Ocean. In a recently published paper in the online scientific journal PLoS ONE, scientists describe how they used satellites to trace the movements of 16 blue sharks from south-west England and the coast of Portugal. The scientists discovered that not only did the sharks hunt at greater ocean depths than had been thought, but that the places they tended to frequent are in the same areas as long-line fishing boats. These boats have a “wall of death” of lines with up to 1,000 hooks each, at depths of some 300 to almost 1,000 feet.
Spanish, Portuguese and Tunisian boats catch an estimated 1.1 million blue sharks each year, to sell in Taiwan or Hong Kong where the fins are processed and sold throughout Asia. Demand for shark’s fin soup, considered a delicacy, has grown as income levels in Asia have risen. Blue sharks are thought to be the species most commonly caught. Since the 1980s, their population has decline by 80 percent in some areas, to the point that they are now classified as “near-threatened” on the IUCN Red List.
“The sharks are having to cross a wall of death across the continental shelf edge off the south west of the UK. The fishermen know what they are going to be catching. Due to the reduction of target species such as tuna and swordfish, they have come to rely on blue shark and mako shark to improve the profit from each trip.”
Prof. Sims says that he hopes that information from the new study will be grounds for establishing marine conservation areas; only 1 percent of the 20 species of shark caught in the Atlantic are currently protected, he says. He is also calling for regulatory organizations like the International Commission for the Conservation of Atlantic Tunas to require fishing companies to report what they catch and where.
The sale of shark fin has been banned in California and New York and other states in the US. But such bans clearly need to be not only state by state and country by country, but worldwide. Though by the time any such regulations may be in place, will it be too late for the blue shark?
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