In the clear waters several miles offshore of Huntington Beach, California, a 40-hectare (100-acre) cluster of shellfish rafts will yield its first commercial harvest this spring. Phil Cruver, founder of Catalina Sea Ranch, says seafood wholesalers have lined up to buy what he expects will be 680,000kg (1.5 million lb) of mussels.
Cruver’s enterprise is also experimenting with the cultivation of seaweed, oysters, sea urchins, scallops and even lobster. “But mussels are our cash crop,” he said. He hopes to be growing seafood across 400 hectares of the ocean 10km (six miles) off the coast within a few years.
In 2012, Catalina Sea Ranch became the first commercial aquaculture operation permitted in federal United States waters, and Cruver’s expansion vision reflects the consensus among some researchers and proponents that growing seafood in offshore waters could be a winning deal as wild fish catches flatline or diminish.
“If we’re going to have more seafood to eat, we’re going to have to start growing it,” said Paul Olin, an aquaculture expert and extension specialist with the California Sea Grant program. “Our population is growing, and the FDA says we actually need to double our seafood intake.”
In a recent study in Nature Communications, Sarah Lester, an assistant professor of geography at Florida State University, found the potential benefits of offshore aquaculture growth can significantly outweigh possible downsides in areas off Southern California, a region of high interest. She and 12 coauthors concluded that there’s plenty of room to grow kelp, mussels and finfish such as striped bass with few impacts on marine life, existing commercial fisheries and the region’s scenic value, as long as the farms are established with careful planning.
“Mussels are a no-brainer,” Lester said. “It’s really easy to farm shellfish and have low environmental impacts.” Production of finfish comes with more environmental downsides. For example, farmed fish may escape into the wild. They may also spread diseases. But, she said, “We found that if you’re strategic about where you site finfish farms, we could have minimal impacts, at least in terms of space.”
Southern California’s waters are relatively calm – an ideal place for floating farms, which is one reason the aquaculture industry has had its eyes on the area for years. In addition to Catalina Sea Ranch, the Hubbs-SeaWorld Research Institute has partnered with private investors and is seeking permits to grow yellowtail jack in a venture called Rose Canyon Fisheries that would be the United States’ largest offshore fish farm. Generally consisting of production facilities anchored in more than 20m (65ft) of water, offshore fish farms produce salmon, tuna and a variety of other species around the world, as well as in a few U.S. states like Hawaii and Washington.
While farming fish and shellfish is not a foreign concept in California – trout, oysters, abalone, sturgeon and other species are produced commercially in fresh- and saltwater facilities – growing seafood offshore is a largely unexplored frontier.
Today, however, the oceans are a crowded place with competing interests. In their research, Lester and her colleagues developed a modeling framework for marine spatial planning to look at whether it might be possible to pinpoint ideal places for future facilities where trade-offs are minimal.
Their model looked for siting plans that would limitthe risks of aquaculture farms spreading diseases to wild fish, harming halibut habitat, impacting fishing activity and marring the views of coastal residents. They found plenty of win-win options.
For example, the study concluded that unrestricted mussel farming below large floating platforms could prevent halibut fishermen from accessing certain areas, potentially shaving off 7 percent of the region’s commercial halibut fishery. However, limiting mussel farming to 25 percent of its full potential, with farms located in the most strategic of sites, they estimated, would still produce $2 billion in mussels while only reducing the halibut fishery’s value by 0.2 percent, or $3,700 in annual profits. In other words, farming mussels off the coast of Southern California would make economic sense, they found.
Currently, the U.S. imports most of its seafood. But doing so may get harder. Olin said that as Asian nations grow wealthier, they may consume more of the seafood they currently export. And Lester believes that shifting more of the world’s aquaculture production into U.S. waters would benefit the ocean overall. Much of the country’s imported fish and shellfish is also already farmed – just not in U.S. waters, where environmental regulations are usually stricter, Lester noted. “So, you may be just transferring the impacts to some other place,” she said.
In fact, she and her coauthors were so confident in U.S. environmental standards that they “assumed best-management practices” for each type of farm they incorporated into their models.
Casson Trenor, author of “Sustainable Sushi” and director of ocean conservation at SoulBuffalo Expeditions, thinks it’s foolhardy to assume that environmental laws will offer adequate protections. “Just look at what happened in Washington last summer – they had salmon pens floating in Puget Sound that were falling apart, and hundreds of thousands of fish escaped,” he said.
He is referring to a recent disaster in which Cooke Aquaculture Pacific’s salmon pens ruptured, releasing thousands of fish near Cypress Island. The negative publicity fired up a campaign to end open-water Atlantic salmon farming in Washington and state lawmakers recently passed a bill that will banish the pens from state waters by 2025.
“They kicked them out – they said, ‘No more open-ocean salmon farms,’ and they did that for a reason,” said Bill Foss, the co-owner of McFarland Springs Trout Farm, a shore-based trout farming company in Northern California.
Foss believes farming of fish and shellfish should be restricted to land-based sites where water is circulated through tanks and operators have full control of the animals’ environment and can use more environmentally friendly feeds.
Other aquaculture producers, however, hope to reduce environmental risks by putting their farms farther away from sensitive coasts, although permitting in federal waters is difficult.
Hubbs-SeaWorld’s yellowtail farming operation has been in the planning stages for about a decade and has drawn opposition from environmentalists concerned about pollution and the potential impact on wild species. It may be another five years before the company’s fish is available on the market, said Hubbs-SeaWorld chief executive Donald Kent. His operation, which would be 6.5km (4 miles) out, must receive formal approval from the National Oceanic and Atmospheric Administration, the U.S. Army Corps of Engineers, the Coast Guard, the California Coastal Commission, the U.S. Environmental Protection Agency and the California Department of Fish and Wildlife.
The plan is to eventually – perhaps 10 years in the future – have approximately 30 hectares (70 acres) of floating pens on the ocean’s surface.
“It’s really a small amount of space, and if you put it in the right spot, it’s possible to have almost no impact,” he said.
Kent said he plans to raise as much as 5,000 tons of yellowtail per year, using a soybean-based feed, rather than one made mostly of fishmeal, and he hopes to raise the bar on environmental standards for aquaculture. Olin, who has helped in the research phase for the Hubbs-SeaWorld project, said advanced technology, including remote monitoring systems, can minimize risks of fish escaping enclosures.
“If we can do this right, we can set high standards that other countries will hopefully follow,” Kent said.
Correction: Sarah Lester said farming shellfish can have low environmental impacts, not none. This article was also updated to reflect that Lester’s modeling was developed to inform the marine spatial planning process.