Can sushi ever be sustainable?

http://www.theguardian.com/environment/2015/may/17/is-sushi-sustainable

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Unusually, this is a subject where luxury consumers and eco campaigners share a symbol: the bluefin tuna. Nature lovers revere this warm-blooded fish, capable of crossing oceans then finding its way home again. Yet it also represents status on a plate: in 2013 one fetched over £1m in Tokyo.

It has not always been so in demand, Newfoundland bluefin used to be fed to cats. But now tuna fuels the global appetite for sushi. The International Union for the Conservation of Nature estimates that the Pacific bluefin population has declined by 19-33% over the past two decades, mainly to satisfy demand for sushi and sashimi. Japan eats 80% of the world’s bluefin. But an estimated 10,000 tonnes of tuna are consumed as sashimi in Europe each year from five major species: skipjack, yellowfin, bigeye and albacore, as well as bluefin.

“Tuna stocks are in serious decline, with too many boats chasing too few fish, along with widespread illegal fishing,” according to the Pew environment group. But can it ever be OK to eat? To help navigate these waters, arm yourself with lists and guides, including Greenpeace’s Red List. Some trail-blazing businesses have majored in the traceability of their sushi – Moshi Moshi, the UK’s first conveyor-belt sushi restaurant, founded pisces-rfr.org, which is a guide to responsible fish restaurants .

Developing countries represent 50% of global fish exports. The idea should be that high-value fish are exported and low-value fish imported with the revenue, meaning there’s a common-sense flow of money (this brings in foreign-exchange revenues of $25bn) and protein. Unfortunately a study by the WorldFish Center found that poor countries are left with a protein gap as fish export revenues are captured by elites and spent on luxury goods (such as imported sushi).

Both luxury consumers of sushi and eco campaigners dislike farmed fish – it tastes inferior and takes juvenile stock from the wild. But researchers at Kindai University can now raise bluefin tuna from larvae – they claim it’s a breakthrough. Though most of us eat more farmed fish than we admit (just 10% of salmon is now from wild catch), penned tuna isn’t what we have in mind when we think sustainable. But given the global appetite, it might be the only way to have our (posh) fish and eat it. The ethics of raising a magnificent apex species in a cage are dubious – tuna can swim up to 80km an hour, and half of penned tuna die in collisions. But “sushinomics” will ultimately override ethics.

Green crush

Lima’s Pan-American Highway is the place to find billboards that keep on giving. The first appeared two years ago when, in a drive to attract more students, the Peruvian city’s University of Technology and Engineering came up with an ingenious design. With a fast-growing population – of more than 8 million – Lima is dogged by water scarcity, but the air is exceptionally humid, sometimes up to 98%. The billboard design sucks that humidity out of the air and turns it into potable water, using a reverse-osmosis system and five small generators. Now UTEC has gone further and upgraded the water-harvesting billboard to an ‘air orchard’, running the filtered water through drip irrigation pipes and creating a hydroponic garden to grow lettuces.

Greenspeak

Heat stress {hī:t strais} noun Experienced by Australian workers and the economy as global temperatures climb. Downing tools leads to 0.4% loss of GDP (less than it would cost to cut net carbon emissions to zero by 2050).