A hammerhead shark caught in a fishing net. (Photo: pewtrusts.org)
Simple changes to fishing gear could lower shark deaths: report
Wednesday, November 16, 2011, 16:30 (GMT + 9)
Simple adjustments to fishing gear could sharply cut the bycatch of sharks worldwide, according to a new global scientific review by the Pew Environment Group.
Fisheries Bycatch of Sharks: Options for Mitigation outlines practical options for reducing shark injury and death from commercial fishing, which is a leading cause of shark population decline.
Pew's Ocean Science Division worked with two scientific experts to research options to reduce shark bycatch.
The researchers determined that feasible modifications include changing the type of bait; switching the material used to create leaders which attach fishing lines to hooks; and altering the shape of hooks.
Fishers sometimes use wire leaders to maximize shark catch, but replacing the wire with nylon can let sharks escape because they can bite through the line.
"Banning wire leaders and not allowing vessels to retain certain species would help reduce the vast number of sharks caught and killed in Atlantic fisheries," said Jill Hepp, manager of global shark conservation for the Pew Environment Group. "The International Commission for the Conservation of Atlantic Tunas (ICCAT) meeting is a good place to build support for using some of these new methods to avoid catching sharks in the first place."
The scientific review, released at the annual meeting of ICCAT in Istanbul this week, reports that in the Atlantic Ocean off the US coast, sharks made up 25 per cent of the total catch of the pelagic (open ocean) longline fishery between 1992 and 2003. In contrast, in 2009, fishing vessels belonging to ICCAT members reported catching 58,100 tonnes of blue sharks, 264 tonnes of porbeagles and 5,605 tonnes of shortfin makos in the Atlantic.
Still, the convention's scientific committee said that in recent years progress has been made to protect bigeye thresher, oceanic whitetip and hammerhead sharks there, and advised that silky sharks should benefit from the same level of protection, as these animals were classified in ICCAT's most recent Ecological Risk Assessment as being among the most vulnerable species.
"While enhanced protections are now helping to safeguard certain species, the majority of sharks remain under threat due to countries' overall lack of political will to control the amount of bycatch hauled in by their fishing vessels," Hepp said. "This review spells out clearly that there are plenty of options available to make fishing more sustainable when it comes to sharks, which, coupled with better fisheries management, would go a long way toward protecting these animals."
Oceana revealed this week that less than 1 per cent of the highly migratory sharks reported caught in the Atlantic are protected from overfishing by ICCAT. Oceana’s new report reads that 75 per cent of the highly migratory shark species caught in ICCAT fisheries are classified as threatened in parts of the Atlantic by the International Union for the Conservation of Nature (IUCN).
Oceana is also urging ICCAT to address the overfishing of Mediterranean swordfish and the bycatch of vulnerable species including sea turtles and marine mammals in these fisheries.
- ICCAT meeting results in more stringent conservation of sharks
By Natalia Real