Panel of researchers cites benefits of offshore fish farming

Moderator Drue Winters and panelists Don Kent, Jesse Trushenski, Rebecca Gentry and Seth Theuerkauf (clockwise from top left)
Moderator Drue Winters and panelists Don Kent, Jesse Trushenski, Rebecca Gentry and Seth Theuerkauf (clockwise from top left) discuss the benefits of aquaculture at a virtual congressional briefing.
(Elisabeth Frausto)

Webinar comes as the Pacific Ocean AquaFarms project proposed for about four miles off Bird Rock is under review by the EPA. Environmental group San Diego Coastkeeper remains opposed.


Offshore aquaculture not only increases the global seafood supply but also serves to temper or mitigate the effects of climate change, according to researchers who spoke at a June 29 online congressional briefing presented by the American Fisheries Society and the National Oceanic and Atmospheric Administration.

“The first and last word in aquaculture in the United States is ‘conservation,’” said Jesse Trushenski, chief science officer and vice president of animal welfare for Riverence, the largest producer of farmed rainbow trout and steelhead in the Americas.

A proposed Pacific Ocean AquaFarms project, spearheaded by the Hubbs-SeaWorld Research Institute and Long Beach-based investment group Pacific6 Enterprises, aims to produce up to 5,000 metric tons of yellowtail fish annually in federal waters about four miles off the coast of Bird Rock.

“We’re moving that project forward,” Hubbs-Seaworld President and Chief Executive Don Kent said at the webinar, noting that the project is under review by the U.S. Environmental Protection Agency.

Southern California is “a huge seafood market,” Kent said. “If we can grow our seafood four miles out to sea and put it in our own processing plants instead of growing the fish in Australia and flying it 7,300 miles into our market, it’s a huge opportunity that allows sustainability moving forward.”

Matt O’Malley, executive director and managing attorney for environmental group San Diego Coastkeeper, which has opposed the Pacific Ocean AquaFarms project, did not attend the briefing but told the La Jolla Light that “there is nothing sustainable about offshore finfish aquaculture except sustained damage to our environment. Offshore finfish operations pollute the ocean with fish waste, feed and antibiotics, harm wild bird populations and marine mammals including whales and sea lions, spread disease to native fish and threaten local fishing industries.”

Kent said at the webinar that “we do a wide range of environmental work in several different study areas,” including research of sustainable seafood development.

“What’s been frustrating to us over the years has been this inability to transfer what we’ve learned how to do with these different species into the commercial sector, where the real benefit can be realized,” Kent said.

“The world is hungry,” Trushenski said. “It’s estimated that we need to be producing roughly 60 percent more food by the year 2050” due to population growth.

“We could feed a couple billion more people with more chicken and pork and beef,” but that would require more acres for crop production, she said.

“When we think of aquatic conservation, one of the most important variables is land use and how that impacts watersheds,” Trushenski said.

With more than 80 percent of fish stocks currently “either fully exploited, in recovery from overfishing or unfortunately … still in decline,” she said, “aquaculture has emerged to fill this growing seafood gap.”

Trushenski added that about half the world’s seafood now comes from farms and that “there is more farmed fish and shellfish produced each year than we produce beef.”

“Aquaculture is diverting harvest pressure that would otherwise be applied to wild fish,” she said. “Nearly all fisheries are already at their limit and are likely to become increasingly vulnerable to overharvest as a result of climate change and other stressors. Aquaculture helps by relieving this added pressure, allowing us to meet that growing seafood demand without decimating fisheries.”

Climate change, marked in the oceans by less oxygen and more acidity, leads to “smaller, less robust fish,” Trushenski said.

She said “aquaculture can help us to produce the additional food that we need with a smaller carbon footprint, less consumption of fresh water and reduced emissions of greenhouse gases.”

Seth Theuerkauf, science coordinator with the NOAA Fisheries office of aquaculture, said “American marine aquaculture really presents a unique and really important opportunity in light of climate change.”

“Seafood has long been known to be one of the world’s most traded commodities, and because of that, supply chains can be complex, long and emissions-intensive,” he said. Aquaculture has the potential to shorten supply chains, thereby reducing emissions, he added.

Theuerkauf said the United States is 17th in the world in aquaculture production. “If we’re able to increase our ability to produce more seafood domestically through aquaculture, we’re able to achieve those efficiencies in terms of reduction in emissions,” he said.

Commercial seafood production, Theuerkauf said, also provides benefits such as “removal of excess nutrients from water bodies, provision of habitat for wildlife like juvenile fish and … possibly the buffering of ocean acidification … through seaweed farming.”

“Within the Pacific Northwest, hatcheries have been able to adapt to increasingly acidic seawater by actually buffering intake seawater to boost survival of shellfish within hatcheries,” he said.

Rebecca Gentry, a postdoctoral researcher at Florida State University whose work focuses on marine aquaculture development, said most marine farms are in the ocean and “can have a significant direct impact on the surrounding environment.”

There might be “negative impacts such as nutrient pollution or introducing diseases into wild species,” she said. But there are also “positive effects such as carbon sequestration and nutrient absorption,” depending on where the farm is located, she added.

“We already have the data and models and decision support tools to make good decisions that can account for these factors,” Gentry said. “Specifically, science-informed siting can identify potential farm locations that are productive and profitable, have lower environmental impacts because of the characteristics of the site and minimize conflicts with other ocean uses,” such as military or fishing.

O’Malley told the Light that organizations like San Diego Coastkeeper don’t necessarily oppose all types of aquaculture.

“Other forms of aquaculture, like kelp farming, can offer environmental benefits,” he said. “But offshore finfish farming has shown to be harmful the world over. San Diego should instead be supporting sustainable native, natural fisheries and our local home-grown fishing industry.” ◆