There are a lot of fish in the sea. But their numbers are no match for growing human appetites and the ultra-efficient fisheries that have sprung up to feed our hunger. A shift towards “blue job fisheries is urgently needed, experts say, if the oceans are to nourish future generations as they have in the past.

(Discussions are ongoing at Rio+20 on making international oceans policy more sustainable.)

About three billion people count on fish and other marine species as their primary source of protein, and about 8 percent of the world’s population are fishermen. Until recently, many people believed that the ocean held so much marine life that even such huge numbers of humans could not deplete its bounty.

But since the mid 20th century industrial fishing operations have used ever-improving technology to fish farther, faster, and longerrapidly emptying waters of seafood to satisfy the swelling hunger of Earth’s growing population. Many fisheries have shown steep declines for decades and some studies estimate that populations of large ocean fish are just 10 percent of their pre-industrial levels.

Sustainability is the key concept for successful management of both fish stocks and fisheries jobs themselves, said Rashid Sumalia, director of the Fisheries Center at the University of British Columbia. “Sustainable jobs, to me, are based on taking what the resource can withstand year in and year out. That’s crucial because right now at the moment we are killing future jobs for current ones. That’s not sustainable. That’s not green jobs. You want the jobs you create today not to prevent future generations from having these jobs but we’re front loading jobs because it’s politically more convenient.

Blue jobs fishermen use science-based stock management programs and only harvest sustainable levels of fish.

“Based on stock assessments we can estimate how much fish can be taken out safely, that’s the total allowable catch, Sumaila said. “To me a green fishery is one that takes only the additional growth from a resource, so that we don’t eat up all the capital or the biomass base.

Blue fishermen also use environmentally friendly methods and gear rather than less enlightened techniques that not only harvest too many fish but destroy the habitat they need to survive and reproduce. Using long lines to hook-catch fish, for example, is a blue alternative to bottom-trawling with enormous drag nets.

“The nets just plow up the bottom of the entire ocean, which is crazy, said Sumaila. “It destroys the homes of the fish, the places where they can grow and live. Long lines are more selective and they are also good in the marketbecause those fish are caught nicely they fetch higher prices.

Fisheries managers can employ tools like marine reserves and protected areas and strict catch limits to achieve sustainability while providing blue jobs for generations to come. But they can only succeed if they can overcome pressures that continue to support unsustainable practiceslike simply allowing too much fishing.

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