Fishing nets with “exit holes” being introduced under a project to salvage depleted world fisheries are helping shrimp trawlers reduce unwanted extra catches by up to 70 percent, a U.N. study shows.
Catching shrimp, the world’s most traded marine commodity worth almost $12 billion a year, is hugely wasteful because the fine-mesh nets also scoop up everything from tiny fish to sharks and turtles, which usually end up discarded dead.
The project in 12 tropical nations, including Mexico and the Philippines, “has dramatically cut the unwanted catch of young fish, turtles and other ‘by-catch’ by as much as 30 to 70 percent,” the U.N. Environment Program said in a statement Sunday.
“We are seeing some promising preliminary results,” said Monique Barbut, the head of the U.N.’s Global Environment Facility which is funding a four-year-old project costing more than $9 million.
“Over 60 percent of what is currently caught in the global shrimp fishery is discarded, making it among the most environmentally damaging in the world,” she said.
Worldwide losses -- mostly because young fish are caught before they reach maturity -- are estimated at billions of dollars, adding to problems of overfishing.
New trawler nets include metal grilles that let shrimp through into the main bulb-shape net but stop bigger fish or turtles and force them out through an “exit hole” in the side.
Other types of nets have large holes on the sides near the front -- fish are smart enough to swim out against the pull of the trawler while shrimp lack the intelligence to spot the exit.
The United States is among countries banning wild shrimp imports from nations that do not use such environmentally friendly nets. The U.N.-funded measures also include training, high tech sensors and underwater monitors that help efficiency.
“There are important lessons to be learnt here for other fisheries and indeed across a wide range of environmental challenges from forestry to energy,” said Achim Steiner, head of the U.N. Environment Program.
The project comprised Indonesia, the Philippines, Cameroon, Nigeria, Bahrain, Iran, Colombia, Cuba, Costa Rica, Trinidad and Tobago, Venezuela and Mexico.
The global marine shrimp catch in 2004 totaled 3.47 million metric tons, or four percent of marine capture fisheries by weight, according to Jeremy Turner, head of the fishing technology service at the U.N.’s Food and Agriculture Organization.
Including aquaculture production, shrimp accounted for 16.5 percent of fish products traded by value in 2004, or almost $12 billion out of a total $72 billion.