Andy Coghlan, New Scientist 15 Apr 09;
Huge volumes of captured fish go to waste either because they're non-target species or because fishing fleets make no effort to record and manage non-target species sustainably.
That's the conclusion of an international study (pdf) by WWF, which estimates how much of the fish harvest goes to waste as bycatch, the species thrown back dead into the sea or used for other purposes, such as feed for aquaculture.
WWF says the study reinforces the need for a complete paradigm shift in how fisheries are managed, so that everything taken from the sea is accounted for. What's also needed is a clear and consistent new definition of bycatch to avoid existing disparities in how "waste" fish is recorded and accounted for.
"We want to see everything taken out to be managed in some way to make sure we are fishing within the limits of what's sustainable," says study author, Robin Davies of WWF International.
Davies suggests that from now on, bycatches should include fish that are either unused and thrown back, or fish that are caught but are not currently monitored to check for any species in danger.
Mass waste
Two earlier landmark studies cited by Davies estimated that between 7 and 27 million tonnes of fish go to waste as bycatch.
Davies new study estimates that 38 million tonnes go to waste, some 40 per cent of the total tonnage landed.
"If 40 per cent of the global catch is unused or unmanaged, how can we make sure it's fished sustainably?" says Davies, whose study will appear in Marine Policy later this month.
Davies arrived at the estimates by analysing public fisheries data from 2000 to 2003, covering 44 countries, two oceanic regions (the northeast Atlantic, and the Mediterannean and Black Sea) and global tuna and sharkfin fisheries.
The waste was greatest in sharkfin fisheries, which typically discarded 92 per cent of non-target species.
There were also disparities in what counted as bycatch. In some parts of the world, non-target fish were still utilised. In prawn fisheries in Asia, for example, owners paid their deck-hands in bycatch fish.
Davies also found that the use of technology to allow non-target fish to escape – such as in the prawn fisheries of Europe – was patchy on a global basis.
Monitor system
Equally, there were big differences in how and whether independent observers were allowed on boats to keep records of the species caught, and their fate.
Such a system has been operating in Europe for at least 20 years, and WWF argues that the latest estimates justify installing such systems everywhere. Even in Europe, for example, too many skates and rays are caught and discarded but not recorded.
"Monitors are so important, to show that fisheries are implementing technologies they should, and to get accurate data on bycatch," says Giles Bartlett, fisheries policy officer at WWF-UK. "The key is that they're in place, and part of overall fisheries management plans everywhere," he said. Otherwise, fisheries will continue to collapse.
Mark Tasker, head of marine advice at the Joint Nature Conservation Committee, which advises the UK government on nature management, says the new study is useful and sound. "It keeps the spotlight on the major environmental impact of fisheries, and it's a reasonable attempt to make bycatch estimates with good conclusions," he says.
"We know that 40 to 50 per cent of catches are being killed by being thrown back, and that's not a good thing," says Tasker.
He applauds the attempt to re-define bycatch, but wonders whether management of stocks will itself be difficult to define and implement. "I agree recording of total catch is a good thing, and then you could think about preserving rarer fish caught by accident," he said. "And we all agree that unused fish count as bycatch."
Forty percent of global fisheries catch wasted or unmanaged - WWF
WWF 15 Apr 09;
Gland, Switzerland - Nearly half of the world’s recorded fish catch is unused, wasted or not accounted for, according to estimates in a new scientific paper co-authored by WWF, the global conservation organization.
The paper, Defining and estimating global marine fisheries bycatch, estimates that each year at least 38 million tonnes of fish, constituting at least 40% of what is taken from our oceans by fishing activities, is unmanaged or unused and should be considered bycatch.
“The health of our oceans cannot be restored and fisheries sustainably managed if 40% of the global fishing catch is unused or unmanaged,” says James P. Leape, Director General, WWF International.
When fishing vessels go to sea, they go after their so called “target” catch, but as most fishing gear is unselective, fishing fleets also catch millions of tonnes of other marine life, commonly known as bycatch. The catch of so called “non-target” fish and marine creatures often occurs with no oversight or management.
In redefining bycatch as anything fishers take from our oceans that is “unused or unmanaged,” the paper’s estimates go well beyond previous global estimates, which focus mainly on catch which is thrown away and vary from 7 to 27 million tonnes a year.
“In many cases, fish and marine animals are thrown back to sea dead or dying and currently even if bycatch is used there is no way to tell whether it was sustainable to remove it in the first place. It is an insidious and invisible form of over-fishing.” says Amanda Nickson, Leader of WWF’s Bycatch Initiative and co-author of the paper.
The paper, to be published in an upcoming edition of the leading journal of ocean policy studies, Marine Policy, estimates the proportion of bycatch in 46 fishing countries and two global fisheries, tuna and shark fin.
In the north-east Atlantic, for example, a fifth of that region's total marine catch is tossed overboard. It is likely that the worst case of wasteful fishing is seen in fisheries that target sharks exclusively for their fins where 92% of what is caught is discarded back in the ocean.
“In addition to ensuring that all fishing activities are appropriately managed, simple, proven methods, such as more selective fishing gear and observers on fishing vessels, already exist to reduce bycatch.” adds Ms Nickson. “But they must become the rule, as part of long-term sustainable marine management, and not the exception.”
According to WWF, bycatch costs fishers time and money contributing to overfishing, jeopardizing future revenue, livelihoods, and long-term food security. It’s also a major killer of marine wildlife, putting several species at risk of extinction and drastically altering the sensitive balance of marine ecosystems.
The conservation organization believes that every form of fishing, and the removal of all marine life from our oceans, should be managed for sustainability, and that anything taken from the ocean by fishing activity is considered part of that fishing effort.
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