The finning of sharks is not for the faint of heart. After hauling them aboard their vessels, the fishers cut off their fins, then toss them back into the ocean.\u00a0Still alive, they sink to the bottom where they’re either eaten by other predators or die of suffocation.<\/p>\n
About 100 million sharks are believed to be taken each year, most of them for their fins alone.\u00a0It’s an industry estimated to be worth US$400 million a year.<\/p>\n The blue shark (Prionaceglauca). Photo by Mark Conlin\/NMFS.\n
If one were to believe official trade records over the past twenty years, most fins traded on world markets have come from more abundant “pelagic” species (ones which live in the open ocean) like the blue shark (above).<\/p>\n
Using advanced techniques in barcoding and genetic tracing, scientists are now painting a different picture.\u00a0By analyzing more than five thousand fins from markets on three continents, they still found a lot had come for those “pelagic” populations.<\/p>\n
But they also found “an additional 40 ‘range-restricted’ coastal species” which did not show up in previous records.<\/p>\n
These populations live closer to shore and do not range as widely as those in the open oceans.\u00a0With local jurisdictions providing little protection for them, their populations now face “dramatic declines” and are “typically less abundant.”<\/p>\n
However, even the more common deep-sea species have been falling victim to “chronic exploitation” by fishers who are “collapsing” their populations, too.<\/p>\n
So, if we want to conserve sharks and curb the “unsustainable global trade in shark fins,” conclude the researchers, “stronger local controls of coastal fishing are urgently needed.”<\/p>\n
Their study was published this summer in the proceedings of The Royal Society.<\/a><\/p>\n New DNA tracking techniques are revealing a greater number of threatened and coastal sharks from stockpiles of intact shark and processed fins (pictured). Image credit: Paul Hilton.\n But this is hardly the first cautionary tale pointing to the plight of Earth’s marine life in general and sharks, in particular.<\/p>\n