Fish farms in the Caribbean would make tons of food

Fish farming—or aquaculture—in the Caribbean could produce more than 34 million metric tons of seafood per year—more than two orders of magnitude larger than the region’s current seafood production, a new study shows.

There are only so many fish in the sea and our appetite for seafood has already stressed many wild fisheries to the breaking point. Meanwhile, the planet’s growing population will further increase the need for animal protein, one of the most resource-intensive types of food to produce.

For a new study, which appears in Nature Sustainability, researchers focused specifically on offshore mariculture—ocean-based operations far from shore—a promising alternative to land-based and coastal aquaculture that comes with limited space and high environmental impacts.

“The Caribbean has a large potential for off-shore mariculture,” says lead author Lennon Thomas, a project researcher at the Marine Science Institute at the University of California, Santa Barbara. “And meeting this potential can be accomplished by developing mariculture in a relatively small amount of ocean space.”

The new model predicts the region could produce 40 million metric tons of seafood in less than 1.5 percent of its countries’ exclusive economic zones. This is roughly half of the current global wild fisheries catch, Thomas says. Under current market conditions, farming in just 179 square kilometers, or a mere 0.006 percent, of its marine space, could mean the Caribbean could match its current seafood production.

Three scenarios

Researchers used cobia, a premium fish with high market value that is well suited to farming in warmer waters. The model combined elements like fish growth and habitat suitability with factors such as farm profitability and investment risk. The model provided more realistic estimates of mariculture potential than if it had focused solely on biology or economics.

Thomas’s team considered socioeconomic and political factors to estimate the risk levels associated with investing in mariculture in each of the countries in the region, and came up with three scenarios.

The first considered the results of farming in all suitable areas and the second considered only areas that would show a profit over a 10-year timeframe, at a 10-percent discount rate. The third, most conservative case mirrored the second, but with discount rates between 10 and 25 percent, based on the relative risk of investment estimated for each country.

Biology and economics

Other papers have examined the physical and environmental factors influencing mariculture production potential on a global level, and researchers have previously applied bio-economic models to individual farms.

But the new study is one of the first to analyze mariculture potential from a bio-economic angle at a regional level, says coauthor Tyler Clavelle, a researcher at the Marine Science Institute. This gave the group a better understanding of the tradeoffs when developing farms in different areas within and across countries.

The results in all scenarios are promising. “Even accounting for the economics of an expensive operation like cobia farming, there are large areas of the Caribbean that could be profitable for off-shore aquaculture,” Clavelle says. Trinidad and Tobago and the Bahamas have the largest potential, with roughly 8,500 and 4,100 square kilometers, respectively, of area profitable for mariculture.

One significant barrier to mariculture development in the Caribbean is insufficient capital, the researchers say. Offshore mariculture is a relatively new, and therefore riskier, industry. Adding in the political and economic instability in certain parts of the region creates a higher risk for foreign investors, Thomas says.

Thomas and Clavelle acknowledged that many people distrust aquaculture, believing it is bad for the environment. The researchers suspect the industry suffers this negative reputation because most of it is currently done on land or near the shore, where the farms’ feed, waste, and other inputs can have negative impacts on surrounding ecosystems.

“Offshore mariculture overcomes many of the shortcomings and potential negative impacts that people often associate with coastal or inland aquaculture,” Thomas says. Deeper water and stronger offshore currents can prevent negative water quality impacts from aquaculture and also avoid sensitive nearshore habitats like coral reefs and seagrass meadows.

Location, location, location

“Mariculture is very space efficient. And we have vast expanses of offshore ocean areas,” says coauthor Sarah Lester, an assistant professor at Florida State University who completed her PhD at UC Santa Barbara. “So we can be really selective about where we locate fish farms, choosing locations where profitability is high and environmental impacts are low.”

The model could also apply to other species and regions. Researchers intend to consider these in future work. They also plan to explore how climate change and increasing ocean temperatures will affect offshore aquaculture.

“In the Caribbean, like we see globally, seafood demand is increasing while many wild fisheries have been overfished,” Lester says. “Currently many Caribbean countries import large amounts of seafood—aquaculture offers a promising avenue for economic development and tasty, sustainable local seafood production.”

Source: UC Santa Barbara