Scientists call for deep sea fishing to be outlawed
September 07 2011 Lewis Smith
Photos: Stephen McGowan, Australian Maritime College, 2007/Marine Photobank
Deep sea fishing is so destructive that it should be banned in virtually every part of the world, a comprehensive review has concluded.
Scientists analysing the impact of commercial fishing on deep sea species such as grenadiers and blue ling have found that fish stocks decline so rapidly that the industry is destroying “the Earth’s largest ecosystem”.
Bottom trawling makes the problem worse because it rips up the seabed, killing corals that may have taken thousands of years to grow and causing “profound and lasting damage” to fish and other creatures.
“The deep sea is the world’s worst place to catch fish” said Dr Elliott Norse, president of the Marine Conservation Institute in Belleview, Washington in the US. “Deep-sea fishes are especially vulnerable because they can’t repopulate quickly after being overfished.”
“Killing off life in the deep sea one place after another isn’t good for our oceans or economies. Boom-and-bust fisheries are more like mining than fishing.”
The authors of the report warned that there is even an economic incentive for fishermen simply to take as many as possible as quickly as possible before moving on to another area, knowing the deep sea species are too slow-growing to make it financially worthwhile to catch them sustainably.
Governments intensify the problems because many hand out subsidies to the fishing industry which means boats can operate even when it is otherwise economically unviable. Up to $162 million is handed out in subsidies to deep sea fishing boats, amounting to about a quarter of the value of the catch.
In their report the authors concluded: “The serial collapses that took 50 years in coastal marine fisheries takes only 5-10 years in the deep sea.
“The best policy would be to shut these fisheries down and redirect subsidies currently allocated to them toward compensating the impacted fishers and helping rebuild fish populations in the highly productive waters closer to fishing ports and markets, places far more condusive to sustainable fisheries.”
Until a few decades ago the fishing industry didn’t bother with deep sea fisheries because there were enough fish closer to land. However, with so many fisheries collapsing - almost a third worldwide are now regarded as overfished - the industry pushed further into the oceans to exploit species they had previously avoided.
Orange roughy were highlighted in the report as an example of a deep sea fish that has suffered population crashes since the fishing industry targetted it on a large scale in the 1980s.
Orange roughy and other deep sea fish caught by a research vessell off Tasmania
Individual fish can live for 125 years but, living in the dark depths of the ocean, are slow-growing and do not reach sexual maturity until they are 30.
“Catch levels have either been dramatically reduced or the fisheries closed all together,” said Dr. Malcolm Clark, one of the report authors and a fisheries biologist based in New Zealand. “The same pattern has been repeated in Australia, Namibia, the SW Indian Ocean, Chile and Ireland. It demonstrates how vulnerable deep-sea fish species can be to overfishing and potential stock collapse.”
Dr Daniel Pauly, a fisheries biologist at the University of British Columbia in Canada, added: “Fifty years ago no one ate orange roughy. In fact, it used to be called slimehead, indicating no one ever thought we would eat it. But as we’ve overfished our coastal species, that changed and so did the name.”
The report, Sustainability of deep-sea fisheries, is published in the journal Marine Policy and involved scientists from a range of fields - mathemematicians, marine ecologists, economists, fisheries biologists and experts on international policy.
The found that only a handful of deep sea fisheries can realistically be fished sustainably, and they would need to be well-managed - something that is almost impossible in the high seas outside the control of individual governments - and with low-intensity catch methods.
One example cited by the researchers is the Azores black scabbardfish fishery where the Portuguese authorities have banned bottom trawling. The fish are caught instead by hook and line from small boats.
The report added that should deep sea fishing continue the industry should have to prove they can be managed sustainably: "Those involved in deep sea fisheries should bear the burden of proving their sustainability if these fisheries are to develop, or continue."
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