By Sandy K. Johnson

Seventy percent of the planet is covered by oceans, so it can be hard to envision why there’s any need for aquaculture.

But the populations of the world that rely on fish as their main protein – primarily those in Asia – are growing exponentially faster, putting pressure on the world’s supply of fish.

And beyond that, there are simply fewer fish. “Historically, there were twice as many fish as there are swimming in the ocean today,” said Paul G. Olin, aquaculture specialist, California Sea Grant, UCSD Scripps Institution of Oceanography.

The United States is already a net importer, to the tune of 90 percent of seafood consumed here. That alone creates an imperative to “grow our own” to ensure quality and quantity.

There are plenty of challenges to aquaculture: fish escapes (nearly 1 million salmon escaped from a farm in Chile, for example), predation and disease, altered genetics, pollution, and fish meal issues.

Olin argued that technology has vastly improved cage aquaculture. One European-designed fish farm boasts six mammoth cages that hold 10,000 tons of salmon. A Norwegian-designed circular structure measures 120 yards across.

In the United States, aquaculture is still heavily regulated. Myriad federal agencies have jurisdiction – Environmental Protection Agency, Fish and Wildlife Service, National Oceanic and Atmospheric Administration, Army Corps of Engineers – as well as state agencies. The process runs the gamut. It can take one to three years and cost at least $500,000 to win a permit on the West Coast; on the East Coast, it can cost as little as $3,000 and six months.

The U.S. has some aquaculture success stories, Olin said, citing farmed catfish in Mississippi and oysters in the Pacific.