AN INTERNATIONAL operation will begin next month in the north-east Atlantic in an effort to deal with some of the thousands of kilometres of “ghost nets” that have decimated deepwater shark stocks and become an increasing environmental menace.
Operation Deepclean, a pilot scheme funded by the EU at a cost of over €500,000 will involve four vessels contracted to undertake targeted retrieval of some of the huge sheets of lost, dumped and abandoned nets.
Bord Iascaigh Mhara (BIM) said the vessels will also undertake surveys to estimate the quantity and range of ghost nets in fisheries off Ireland and Britain.
The nets are called ghost nets because they drift in the ocean after being abandoned or dumped and some have been found to be still catching fish and ensnaring other marine life for up to three years.
The fish are caught and die in the nets. The effect has been devastating with stocks of deepwater sharks falling to about 20 per cent of original levels in less than 10 years.
It has been a growing environmental problem since the mid-1990s when a fleet of up to 50 vessels began gillnet fishing on the continental slopes in areas like Rockall and the Hatton Bank.
These vessels, though mostly based in Spain are registered in Britain, Germany and other countries outside the EU such as Panama.
The fishery is conducted in depths between 200 (650 feet) and 1,200 metres, with the main target species being monkfish and deepwater sharks though they also catch other species like halibut and ling. No one is certain how many ghost nets there are either floating or fouling the seabed.
Dominic Rihan, marine technical executive with BIM, said Operation Deepclean will run from June until September and would provide an up to date picture of the scale of the problem.
“One Spanish and three Irish vessels will be involved,” he said, “Four different surveys at different depths lasting 20 days are being undertaken, two by Ireland and two by the authorities in Britain.
“The retrieval exercise will alleviate the problem of ghost fishing and help prevent further fish being caught in these nets. We also hope to get an estimate of the amount of lost nets in the particular areas,” Rihan said.
A joint Irish, Norwegian and British study completed in 2002 estimated that 1,254 kilometres of 600 X 50 metre sheets of nets were being lost every year.
The study, entitled Deepnet, said there “seemed to be a deep reluctance to talk about this fishery, in fact, almost ‘an unwritten law of silence’.” It said the “total amount of loss and discarding of nets is not known, although anecdotal evidence suggests up to 30 kilometres of gear are routinely discarded per vessel per trip.
“It is not known how much and for how long these nets are fishing after they are lost.
“Norwegian investigations in the deep slope gillnet fishery for Greenland halibut have shown that gear losses can be significant and that the nets can fish for at least 2-3 years and sometimes even longer,” the study said.