Books: another side of aquaculture

Four Fish, Paul Greenberg’s examination of overfishing and the rise of industrial sea-farming, is accessible and enlightening without being preachy, writes Luke Jennings.

Four Fish
Paul Greenberg
Allen Lane, 2010

A few years ago, as part of a journalistic assignment, I was crossing the North Sea by nuclear submarine, and just before I was put ashore on the west coast of Scotland, the vessel voided its waste tanks into the waters of the inlet, along whose shoreline extended a salmon farm. If I had been wary about eating farmed fish up to that point, I was doubly so thereafter.

As an angler, I knew what healthy salmon looked like – streamlined bars of silver, full-finned, hard with muscle – and the spongy cadavers I had begun to see on certain supermarket and fishmonger’s slabs, with their stunted fins, deformed gill-covers, and artificially pink flesh, were anything but healthy. Where wild salmon had made epic journeys, growing to adulthood in the ocean before battling up-river to spawn, these zombie-fish had spent their lives in cages, ingesting a murky backwash of growth-pellets and their own faeces. If other people wanted to put this stuff in their mouths, fine. Personally, I’d abstain.

That there’s another side to the aquaculture issue, and that some of the best minds in world science are trained on it, is made clear in Paul Greenberg’s accessible and enlightening Four Fish. Encouraged by his mother, who sensed in the pursuit “a masculine, character-building quality”, Greenberg learned to fish in Long Island Sound, an eastern US estuary. He thought of the sea as “a vessel of desires and mystery, a place of abundance I did not need to question”. With that abundance now in catastrophic decline, Four Fish is an examination of the present-day state of salmon, sea-bass, cod and tuna, and the strategies for their conservation.

What we have seen, he writes of sea fish in general, is a wave of psychological denial of staggering scope. “With wild fish we have chosen, time after time, to ignore the fundamental limits the laws of nature place on eco-systems and have consistently removed more fish than can be replaced by natural processes.” In the US, thanks to ruthless overfishing of the waters off Greenland by the Scandinavians in the 1960s, “there is no longer a popular memory of wild Atlantic salmon as food”.

At the same time, the world now produces more than three billion pounds of farmed salmon annually, in countries as distant as Norway, Chile and Canada. This is hailed as a breakthrough by fish breeders, but as Greenberg observes, these salmon have been reared at the cost of the nine billion pounds of wild fish that have been caught and ground into pellets to feed them. This unsustainable process encourages the spread to farmed fish of polychlorinated biphenyls, or PCBs, a toxic by-product of electronic component manufacture that was dumped into rivers at the end of the last century, and remains in the food chain.

The “quest of quests” for sustainable seafood production is the “closed circle”, with zero feed going into the system. This, for salmon, is now a distant possibility, with omega-3-rich seaweeds replacing PCB-bearing feed-fish, and the salmon’s own waste fertilising more seaweed. Which sounds fine, except that the result wouldn’t in any real sense be a salmon at all, given that a salmon – like every good eating-fish – is essentially a predatory rather than a vegetarian animal.

The story of the domestication of the sea bass is more encouraging. It begins at Hebrew University in Eilat, Israel, and moves to Cephalonia in Greece, and the science is riveting throughout. One of the thorniest problems facing marine biologists was what to feed young captive sea bass: the answer, it turned out, was a genus of tiny shrimp named artemia, which could survive without water in their dried casings for up to a million years, and which had previously been marketed as “pets” by an eccentric entrepreneur who called them “Sea-Monkeys”.

 Today, Greece sends a hundred million sea bass around the world, each one precision-bred to fit a restaurant dinner plate. But the economics are not good. Feed costs are rising and prices falling to the point where the production of sea bass may become unsustainable. The story may not, in the end, be one of success.

“How do you restore an ecology of abundance when even the diminished system is still being plundered by humans?”, Greenberg asks, with reference to the cod. Yet he is not wholly pessimistic. Cape Cod got its name from its proximity to Georges Bank, the greatest of the New England fishing grounds, and in 1994 part of this region was closed to commercial fishing by the US federal government. The time horizon for rebuilding stocks is presently set at 2026. Distant, but not invisible. On the part of the Georges Bank that remains open, cod are harvested by low impact hook-and-line fishing, as wild sea bass are in France. There is a glimmer of hope.

Finally, we join Greenberg in 2001 as, trying his best to forget the destruction of New York’s twin towers a fortnight earlier, he heads out into a choppy sea after tuna, “the wildest things in the ocean”. Behind the boat, the butterfish-chum slick is “punctuated with human vomit”. The beginning of the end for tuna occurred in the 1970s, when the technology for deep-freezing them at sea was invented. Sushi, once an exclusively Japanese food-style, went global, and the price of tuna flesh rose from pennies to hundreds of dollars a pound. Factory ships decimated stocks worldwide, and many believe the bluefin population has imploded beyond recovery. As Greenberg says, “Dining on a 500-pound bluefin tuna is the seafood equivalent of driving a Hummer.”

But it’s not Greenberg’s way to preach; he’s happier letting the facts speak for themselves. There’s some fairly hard-core science in Four Fish, but it’s so skilfully interleaved with the narrative that you absorb it without pain. And in the end, he writes, the battle is with ourselves. Between “the altruism that we know we can muster”, and the primitive greed that lies beneath our relationship with the creatures of the sea.

Luke Jennings is the author of
Blood Knots: Of Fathers, Friendship & Fishing (Atlantic).

Copyright Guardian News and Media Limited 2010