Saving Fish By Farming Them

Boosting aquaculture -- especially in the lagging U.S. -- can help restore wild populations of our sea-dwelling friends.

Know your fish.

Photographer: BORIS HORVAT/AFP/Getty Images

A major turning point in human history was reached in 2014. That was the first year that people ate more farmed fish  than wild, the United Nations Food and Agriculture Organization announced last week in its biennial "The State of World Fisheries and Aquaculture" report.

We humans still caught more wild fish (measured by weight) than we farmed in 2014, but about 12 percent of fish production went to non-people-food uses such as fish meal, which is in turn was fed mostly to farm animals, including fish. The FAO predicted that aquaculture will surpass wild-caught in terms of overall production in 2021, adding:

This development highlights a new era, indicating that aquaculture will increasingly be the main driver of change in the fisheries and aquaculture sector.

It's been quite a few years since humans made the equivalent switch from gathering berries to farming crops, and from hunting wild mammals and birds to raising domesticated ones. The advent of agriculture enabled the rise of civilization; subsequent revolutions in agricultural productivity have made it possible for the earth to support a population of 7.4 billion people.

The rise of aquaculture surely won't have that dramatic an impact on humanity. But it could be a really big deal for the fish. Here's the trajectory of fish "production" since 1950, according to the FAO:

fish production
source: UN Food and Agriculture Organization

The amount of fish being caught in the wild hasn't risen significantly since about 1990. In a few places -- off the coasts of Australia, Iceland and the U.S., for example -- that's partly because of restrictions intended to rebuild fisheries. In most of the world's oceans, though, fishermen aren't catching more fish mainly just because there aren't more fish to be caught.

Rockefeller University's Jesse Ausubel, an environmental optimist who argues that humans may be nearing the point of peak impact on the earth, cites overfishing of the oceans as a big negative exception.  As he wrote last year:

Fish biomass in intensively exploited fisheries appears to be about one-tenth the level of the fish in those seas a few decades or hundred years ago. Diverse observations support this estimate. For example, the total population of cod off Cape Cod today probably weighs only about 3 percent of all the cod in 1815. The average swordfish harpooned off New England dropped in size from about 500 pounds in 1860 to about 200 pounds in 1930. 

If we're going to keep eating fish, then, we need to catch a lot less and farm a lot more.

Strangely, though, fish farming has acquired something of a negative reputation. It's not entirely undeserved -- salmon farms were once rife with disease and pollution, and Southeast Asian shrimp farms still cause lots of problems now. But as Marian Swain of the Breakthrough Institute, an environmental think tank, explained in a highly informative Slate piece in 2014, fish farmers have been cleaning up their act. Now, about half of the seafood varieties that make it onto the Monterey Bay Aquarium's national "Best Choices" list for sustainability are farmed.

The transition from catching to farming is farthest along in China, where 73 percent of fish production is from aquaculture. No other country is even close to China's scale in fish farming.

where fish farmed

The Chinese have been raising carp for more than 2,000 years, but things really took off over the past three decades, with aquaculture production rising from about 2 million metric tons in 1983 to 45.5 million tons in 2014. Carp of various sorts still dominate freshwater fish farming in China, but there's also a big business in raising oysters, clams and cockles along the coast. 

The U.S. ranked 15th in farmed-seafood production in 2014, with less than 1 percent of China's output. The most important aquaculture products, ranked by dollar value as of 2013, were catfish, oysters, crawfish, clams, salmon and trout. So we're still a long, long way from eating more farmed seafood than captured. And now I'm kicking myself for having missed this year's crawfish season.

This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.