And maybe weep for the planet

The New York Times recently published a thought-provoking article on the development of farming for the Atlantic bluefin, the world’s largest tuna.

This is a magnificent fish, as a National Geographic website details:

The Atlantic bluefin tuna is one of the largest, fastest, and most gorgeously colored of all the world’s fishes. Their torpedo-shaped, streamlined bodies are built for speed and endurance. Their coloring—metallic blue on top and shimmering silver-white on the bottom—helps camouflage them from above and below. And their voracious appetite and varied diet pushes their average size to a whopping 6.5 feet (2 meters) in length and 550 pounds (250 kilograms), although much larger specimens are not uncommon.

The NYT article was written by Paul Greenberg who is the author of “Four Fish: The Future of the Last Wild Food.”  See his website.

Here’s some of what was written in that NYT article:

IN the wide expanse of the wild ocean, there is perhaps nothing more wild than the world’s largest tuna — the giant Atlantic bluefin. Equipped with a kind of natural GPS system that biologists have yet to decode, the bluefin can cross and recross the Atlantic’s breadth multiple times in the course of its life. Its furious metabolism enables the fish to sprint at more than 40 miles an hour, heat its muscles 20 degrees above ambient, and hunt relentlessly at frigid depths in excess of 1,500 feet.

I didn’t realise that these fish are warm-blooded, a rare trait among fish, but the more important fact is that a bluefin tuna is likely to eat between 5 lbs (2 kg) and 15 lbs (6 kg) of wildfish for every pound of body.  Thus a fully grown bluefin of around 550 lbs (250 kg) represents a diet of anywhere between 2,750 and 8,250 lbs (340 -3,750 kgs) of wildfish. Back to the Greenberg article:

The Stanford economist Rosamond Naylor pointed out in a recent paper in The Proceedings of the National Academy of Sciences, that there was not too much room for adding species to the world’s aquaculture portfolio.

“Most forage fisheries,” Ms. Naylor wrote “are either fully exploited to overexploited or are in the process of recovering from overexploitation.”

If she is right — and if bluefin tuna farming is ramped up to the level of salmon farming, which produces more than two billion pounds a year — the effect on forage fish, the foundation of the oceanic food chain, could be devastating. A worldwide overharvest of forage fish could damage not just bluefin tuna populations but other important commercial species that also rely on these fish for sustenance.

In other words Rosamond Naylor is warning us, all of us that eat fish, that we could put at risk the entire ocean’s food chain.  And what scares me is that humans have shown a real propensity to put their short-term needs totally above any long-term protection of the planet we all live on.  How crazy is that!

The NYT article closes thus:

If Atlantic bluefin is not farmed, it will most likely become an even more scarce luxury item. Global fishing moratoriums on the species have been proposed (and then rejected by the many nations that catch bluefin). But other options being discussed include drastically reducing fishing quotas in the next few years and closing spawning grounds in the Mediterranean and the Gulf of Mexico to fishing entirely.

Perhaps, in the end, this is what the Atlantic bluefin tuna might really need. Not human intervention to make them spawn in captivity. But rather human restraint, to allow them to spawn in the wild, in peace.

Amen to that.

By Paul Handover