MONTEREY, Calif. — Farmed fish has gotten a bad rap, but it’s the only way the world is going to feed the additional 2.4 billion people expected to be added to the Earth’s population in the next 34 years, experts told a sustainable food conference.
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. He spoke at a conference on sustainable food at the Monterey Bay Aquarium earlier this month.
The rising human population isn't the only issue. As standards of living rise, people eat more protein and especially more 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 is a challenge. In most of the world, all the land that can be planted already is planted. Plowing under the marginal land that's left would only lead to deforestation and land degradation, which only contributes 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 only take care of between 1% and 5% of the coming demand, Gaines said.
The only option, experts at the Monterey conference said, is aquaculture. Currently just 15% of world animal protein consumption comes from aquaculture but that can quickly be ramped up.
An ongoing issue is that ocean-going fish, especially salmon, must be fed food that contains omega 3 fatty acids to taste like their wild counterparts. While fresh water fish such as tilapia and catfish don't need this, historically salmon have been fed feed that contains ground fishmeal. That meant that it could take as much as two pounds of fish to grow one pound of salmon.
Now multiple companies are working to create algae and yeast-based feeds to replace fish meal and make fish feed fully vegetarian, said the University of Arizona's Fitzsimmons said.
While there’s still room to improve overall, ongoing technological and management advances mean that fish farming has become a very ecologic way to produce food.
“The potential is for aquaculture to be a highly sustainable, low-impact protein,” UCSB's Gaines said.
"Asia leads the globe. 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.
In Asia, most fish are farmed inland in ponds. Traditionally, agricultural waste was added to the ponds. That fed algae that in turn fed zooplankton that the fish ate, making the system very ecologically friendly and sustainable.
Fish isn’t the only aquaculture product being produced there. 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.
Long ramp up
Americans need to start eating a wider variety of seafood than just shrimp, tuna and salmon, the experts said.
Currently 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 Peet.
“On land we eat four things: cows, pigs, chickens and lambs. But in aquaculture there are hundreds of different species, the diversity of options choices is so much richer than from the land,” said Gaines.
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.
“People are going to eat it everywhere, it’s replacing wild caught fish all over the place,” he said.
And it's 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.