Some time in the 1990s, production of sea-caught fish flattened and stagnated. Ever since, all the growth in the global fish supply has come from aquaculture, or fish farms. In 2012, about two-thirds of all fish–67 million tons out of 158 million tons–were grown in controlled environments.
That growth is impressive but will need to keep going, as a new report shows. It takes an optimist to imagine wild fish stocks will ever grow significantly again. “Thirty percent of the world’s fish-stocks are overfished,” says the report’s lead author Richard Waite of the World Resources Institute. “So, the level we have today isn’t sustainable. We actually need to reduce wild fish catch in the short term to get back even to replacement level.”
Studies show that reducing catches in the short-term could lead to significant long-term gains. But, the reality is, many countries are not prepared to do that, and this gradually makes replenishment of natural populations more difficult.
The report says the world will need to double farm fish production by 2050 if we’re going to meet the demands of growing population. The developing world in particular is likely to need a lot more aquaculture. The World Resources Institute report looks at how to raise production without the environmental impacts associated with intensive aquaculture. In the past, that has been a real challenge:
To date, intensification has led to a decrease in the use of land and freshwater per unit of farmed fish produced…[The] intensification has also led to an increase in the use of energy and fish-based feed ingredients, as well as an increase in water pollution, per unit of farmed fish produced.
Disease risks also rise in intensive systems. These tradeoffs suggest that “sustainable intensification” is easier said than done–and that efforts to intensify aquaculture production should aim at mitigating the negative impacts of intensification.
The group, a global research nonprofit based in Washington, D.C., makes five recommendations.
There’s a need to build more efficient, more sustainable aquaculture systems. “At the moment, [aquaculture is] really decades behind terrestrial livestock farming. There are improvements we could make in breeding and in feeds, disease control, and production systems. If combined, we could be producing more fish with not much more impact,” Waite says.
In developing countries, fish farms are often run by small-holding farmers who build haphazardly. By taking a larger-scale planning approach and introducing zoning, governments can enforce more organized developed and improve overall productivity. (That may, though, mean larger farms, and perhaps less employment.)
Governments can issue regulations, tax breaks, subsidies, and incentives to encourage more sustainable practice, Waite says. And they can also get behind industry certification organizations like the Marine Stewardship Council, which now covers about 200 fisheries worldwide.
At the moment, there’s a lack of comprehensive data and monitoring for many places. Waite would like to produce the equivalent of the Global Forest Watch for fisheries–that is, a live mapping platform continuously fed with satellite data and on-the-ground intelligence. “A platform integrating these technologies could help governments improve spatial planning and monitoring, help the industry plan for and demonstrate sustainability of operations, and help civil society report success stories and hold industry and government accountable,” the report says.
At the moment, a lot of wild-caught fish ends up becoming fish feed, which goes to fish farms. “It doesn’t make any sense to feed wild fish to farmed fish. It’s not efficient,” Waite says. “If we want to improve global fish-stocks, we should be eating fish lower on the food chain that either don’t eat wild fish or do it smaller amounts.” That means steering clear of high-end salmon, and eating tilapia and catfish instead. Mussels, clams, and scallops are even better. “They’re the closest thing to a free lunch from an environmental perspective. They don’t use any land, freshwater, or feed,” Waite says.