Monday, October 31, 2011

Fraction of Really Big Question

Did you see the photo of the little tyke in Manila who has been designated as Number 7 Billion contemporary human? Handy graphic to lead into very serious newspaper articles about population and natural resources, which ineluctably lead to mention of the consensus estimate that there will be a Number 9 Billion baby sometime in the decade of the 2050s and then next an allusion to the Big Question of whether the world can feed nine billion people. Frequent resort to the word "Malthusian."

Many people I know are thinking about the agricultural requirements of feeding nine billion. Can it be done and, if so, through what means and with what consequences to nature and human societies? One subset of that larger inquiry – and one I've been working on – has to do with getting animal protein from the sea. Can humans adopt the agricultural model for the oceans? Will they? Should they?

Well, they (we) can try. But on current evidence, it's hard to envision an aggregate worldwide mariculture that is simultaneously capable of contributing a significant fraction of the human diet as well as protecting marine biodiversity and the habitats that sustain it. So far, it looks as if raising shrimp and raising oysters, performed to reasonable standards of best practice, don't cause intolerable damage to near-shore systems. Let's postpone defining intolerable.

But the biggest saltwater farm animal, by far, is the salmon, and salmon-farming is not good. Salmon-farming works, obviously. And if you put aside concerns about taste (versus wild salmon) and antibiotic loads, farmed salmon does pretty well on a pumpernickel bagel with a shmear. The problems are these: 1. The salmon is a carnivore. Salmon farmers feed their charges meal made from grain and other fish. Salmon farming shares all the problems of terrestrial livestock confinements and adds the additional whammy of depleting wild fish stocks. 2. The domesticated salmon escape their pens, breed with wild salmon, and produce offspring discernibly less robust than their wild parent. Any salmon needing to swim upstream better be robust.

Maybe there are ways to make good money and help feed billions of people by raising non-carnivore marine animals that contribute to the well-being of a particular marine ecosystem. After all, land herbivores have a big role in organic farming. So let's not be dogmatic. On the other hand, don't make any bets.

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