Fish farms: Food wave of future
IT’S WHAT’S GOING TO BE FOR DINNER As Earth population swells, is aquaculture next sustainable wave?
Elizabeth Weise MONTEREY
Farmed fish has gotten a bad rap, but it’s the only way the world is going to feed the 2.4 billion people expected to be added to the Earth’s population in the next 34 years, experts told a sustainable food conference here last week.
With the world’s arable land maxed out and wild seafood overfished, aquaculture is the one place we can look to produce enough animal protein for all those extra mouths, said Steve Gaines, a professor of marine biology at the University of California-Santa Barbara and lead investigator for the university’s sustainable fisheries group.
And as standards of living rise, people eat more protein, especially meat. In China, for example, annual meat consumption has risen from 28 pounds per person in 1982 to 138 pounds in 2015.
Growing enough crops to feed more pigs, chickens and cows isn’t possible because most of the world’s land that be planted already is. Plowing under the marginal land that’s left would only lead to deforestation and land degradation, contributing to climate change, said Gaines.
Turning to the world’s oceans doesn’t help. Analysis of global fisheries, even if all were sustainably managed for maximum production, would take care of only between 1% and 5% of the coming demand, Gaines said.
Aquaculture, though, is a hard sell in the United States, panelists said, blaming U.S. prejudice on NIMBYism (i.e. Not in My Backyard). Americans seem content to eat farmed salmon, shrimp, oysters and other species when produced far away but don’t want to see fish farms and pens in their pristine waters at home.
And a negative connotation with fish farming persists among the more eco-conscious because of early unsustainable attempts, like farmed salmon and shrimp, in South America and Asia.
Asian seafood producers have been cleaning up their acts, but damaging stories about aquaculture there continue to make the rounds, said Kevin Fitzsimmons, a professor of aquaculture at the University of Arizona in Tucson. He says he often hears Americans complain about agricultural leavings and animal waste being used in fish ponds in Southeast Asia, a practice that’s actually both sustainable and deeply rooted in the culture, he said.
“In the United States, if somebody puts chicken waste in their garden, they’re an organic farmer and it’s wonderful. But if they put it in a fish pond in China, we say they’re trying to kill us,” he said. Today a wave of innovation and investment has meant that aquaculture overall is much more environmentally friendly and efficient than it once was.
An ongoing issue is that oceangoing fish, especially salmon, must be fed food that contains omega-3 fatty acids to taste like their wild counterparts. While freshwater fish such as tilapia and catfish don’t need this, salmon traditionally have been fed feed that contains ground fishmeal. That meant that it could take as much as 2 pounds of fish to grow 1 pound of salmon.
Now multiple companies are working to create algae and yeastbased feeds to make fish feed fully vegetarian, Fitzsimmons said. While there’s room to improve, ongoing technological and management advances mean that fish farming has become a very ecological way to produce food.
“The potential is for aquaculture to be a highly sustainable, low-impact protein,” Gaines said. Asia, which has practiced pond and rice paddy-based aquaculture for millennia, produces more than 70% of all seafood from aquaculture, according to the Food and Agricultural Organization of the United Nations.
“Thanks to aquaculture, the global per-capita supply of fish is at an all-time high,” said Edward Allison, a professor of marine and environmental affairs at the University of Washington in Seattle.
Fish isn’t the only aquaculture product being produced in Asia. Korea has developed a commercial method for making high quality paper using red seaweed, said Fitzsimmons. Someday seaweed farms planted just offshore of large cities could take up farm runoff nutrients and CO2, lowering pollution and climate-changing gasses.
A city “could actually be carbon-positive” just from seaweed farms, Fitzsimmons said.
Americans tend to think salmon when they think aquaculture. Today, 78% of the salmon Americans eat is farmed, according to research by Oai Li Chen at the University of Washington. However, as a whole, salmon makes up just one-fifth of world aquaculture production, said Corey Peet, a founding member of the Asian Seafood Improvement Collaborative.
Popular farmed fish in Asia include carp, tilapia Asian sea bass, snappers and groupers, said Fitzsimmons. His favorite is tilapia, which he said is to seafood as chicken is to poultry.
And tilapia isn’t just for eating. He proudly showed off his vest, which looked to be made of black leather but was in fact tanned tilapia skin made in Brazil. “You can really do a lot with it,” he said.
A boy in India holds a milkfish, which has been grown in fish ponds in Asia for centuries. The system is ecologically friendly.
A series of commercial fish ponds in Shandong, China