A team of international scientists has called on governments to scrap their multimillion dollar subsidies to deep-sea fishing vessels which operate "like roving bandits", trawling the ocean bottom, ripping up ancient coral and sponge beds and plundering populations of slow-growing fish such as Patagonian Toothfish and Orange Roughy.
The vessels use weighted nets "the size of Rhode Island" which scrape the bottom of the sea thousands of metres deep, destroying slow-growing fish populations that will take centuries to recover.
The American Association for the Advancement of Science held a press briefing at its annual congress in the US on Sunday, where scientists and fisheries economists called on governments to abolish the massive fuel subsidies which keep destructive bottom trawlers in business.
The association said in a statement on Monday that scientists from the University of British Columbia, Rashid Sumaila and Daniel Pauly, had established that subsidies paid to bottom-trawl fleets around the world amounted to more than $152-million (about R1-billion) a year. These vessels not only destroyed the marine ecosystem, but contributed to global climate change by burning 1,1-billion litres of fuel a year.
"There is surely a better way for government to spend money than by paying subsidies to a fleet that burns 1,1bn litres of fuel annually to maintain paltry catches of old growth fish from highly vulnerable stocks, while destroying their habitat in the process," Pauly said.
Researchers from the Memorial University in Newfoundland have found that 40 percent of deep-sea marine fauna in the north-west Atlantic were in decline. This was only for those deep-sea species for which data was available.
The scientists said that this highly destructive form of fishing would be unprofitable without heavy government support. Without subsidies, it would operate at a loss of $50m a year. Most of the subsidies pay for fuel which enables fishing vessels to travel way beyond the 200-mile exclusive economic zones around coastal countries, and to fish on the high seas.
"In international waters many of the fisheries are virtually unregulated (and) operate like roving bandits, using state- of-the-art technology to plunder the depths," the AAAS said.
It said the deep sea was the largest wilderness on the planet, with valleys deeper than the Grand Canyon and high mountains called seamounts. As the fishing industry depleted coastal fisheries, so the industry is moving to dragging the seafloor more than 1,6km deep.
"Super-trawlers over 600ft long are equipped with flash freezers and giant fuel tanks that allow them to stay at sea for months, mining rich areas of fish to depletion, then moving on," the statement said.
Some vessels used chains to rip up coral beds hundreds of years old so they would not tear their nets.
The Orange Roughy, which is found in the Southern Ocean, has been so badly hammered by deep-sea fishing that Australia has declared it a threatened species. Krista Baker of Memorial University said: "When you buy Orange Roughy you are likely eating a fish that is at least 50 years old. Some can be as old as 150 years old, which means you could be eating a fish that was born when Lincoln was president."
Because they live to very old ages, they are slow to mature sexually, and are therefore vulnerable to over-exploitation.
The AAAS said the solution was not to fish deeper, but to manage coastal fisheries better, where fish are fast growing.