The difference between farmed and wild salmon sounds pretty clear, but in fact it's an example of how blurry the origin of seafood can be. The farms depend on wild-caught forage fish to feed the salmon; meanwhile, wild salmon runs are often supplemented with young salmon raised in hatcheries. Now a team of researchers is proposing a new label—hybrid seafood—to better categorize the source of seafood and its impacts. "To tell if seafood is environmentally sustainable, you need to know more than whether it's fished or farmed," says Dane Klinger, a doctoral student at Stanford University in Palo Alto, California.
Seafood production encompasses a spectrum of techniques, stretching from wild-caught fisheries such as anchoveta to straight-up aquaculture of mussels and other creatures. In the middle is a gray zone where you find aquaculture-enhanced fisheries and fishery-enhanced aquaculture. A group of scientists, led by Klinger and Mary Turnipseed, now a fellow with the Gordon and Betty Moore Foundation's Marine Conservation Initiative, investigated this issue as part of a project on sustainable seafood at the National Center for Ecological Analysis and Synthesis in Santa Barbara.
Fisheries organizations categorize seafood as coming from either fisheries or aquaculture. Sorting out the origins more accurately would have several advantages, the team argues in an article in press at Marine Policy. First, the new classification would help researchers better understand the potential for growth in fisheries. Yields from wild-fisheries that are stocked, such as Chesapeake oysters, can have the potential to grow faster than ones that aren't. Better terminology could also reduce the risk of double-counting seafood catches and underestimating the environmental impact; for example, the authors note that roughly 70% of Atlantic herring caught in the Gulf of Maine is used for lobster bait.
Aquaculture has issues, too. "Both aquaculture and fisheries managers often overlook the environmental impacts of stocking aquaculture operations with wild-caught individuals," the authors write. Some aquaculture operations collect wild shrimp to grow up in their farms (although research has helped lessen the need for this) and bluefin tuna are ranched from juveniles caught in the open ocean. Keeping better track of this sourcing will help slow the decline of bluefin, the researchers argue.
The United Nations' Food and Agriculture Organization is the global clearinghouse for national fisheries data, and FAO should start asking for numbers on hybrid seafood production, the team says. "For the most part, managers, regulators, and scientists at national and regional levels have this information available to them," Klinger tells ScienceInsider. "Adding a new hybrid category to national and international seafood production record keeping would easily make these data available to global analysts, with little extra effort required by individual countries."
Elizabeth Havice, a political economist at the University of North Carolina, Chapel Hill, who is not an author, calls the classification "a very useful idea conceptually because it draws attention to often invisible connections between 'capture' and 'culture' fisheries," although she thinks data collection could be a significant challenge. Marine scientist Jennifer Jacquet, who will join New York University's Environmental Studies Program in September, agrees that the new classification would be useful for researchers and managers. But she rues what it represents: "a slow slide toward domestication of the oceans."