One of the more thoughtful voices shaping discussion of fisheries and aquaculture in the public sphere in the US is Paul Greenberg. The author and fisherman is perhaps best known for his book Four Fish that tells the story of fish that Americans are overeating: cod, salmon, bass and tuna. The PBS Frontline documentary series recently aired a film by Paul called The Fish on My Plate about his year of eating fish every day. At the core of the piece was the question of what fish should I eat that’s good for me and also good for the planet? The film was based on the forthcoming book The Omega Principle about omega-3 fatty acids and how the health of the oceans is connected with personal health. The documentary is about Paul’s journey and exploration of the subject during the year of his self-imposed diet. 

It first took him to Peru to examine the anchoveta reduction fisheries. The piece raised questions about whether the fishery is being properly managed under pressure from the fishing companies. Salmon farming, which is given tough scrutiny throughout the film, is credited for driving the development of the fishmeal industry. Incidentally, the recommended daily dose of omega-3 fatty acids is equivalent to the fillets of two anchovies.

The documentary dedicated inordinate attention to salmon farming, although this is understandable because Greenberg’s frame is that of an engaged and concerned American consumer, the main audience for the documentary. There was no mention of the current role of fish produced in aquaculture for the food security of many millions in developing countries around the world, no discussion of freshwater aquaculture, and scant mention of shrimp. Paul called farmed salmon the “poster fish for today’s industry.”

The documentary sets up the controversy around salmon farming by juxtaposing separate visits and interviews with Per Grieg, head of one of the five families that controls the salmon industry, and the eco-warrier Kurt Oddekalv. Per said that the “NGOs are vocal and clever with media” and that they have “influence on politicians and politics in Norway.” Kurt showed off his “feces theater” documenting waste solids accumulation beneath net pens with video cameras. The troublesome issues were clearly identified as escaped salmon that mixes with wild fish populations, sea lice, and overall pollution.

Greenberg acknowledges that Norway’s salmon farmers have been improving, choosing better sites and limiting ecological damage and becoming less wasteful and polluting. With selective breeding, better feeds and improved farming techniques, salmon farming has become more efficient. Greenberg highlighted some of the technical advances in salmon farming, including using fish processing waste trimmings, filtering POPs from fish oil, using astaxanthin from Paracoccus carotinafaciens bacteria, no chemical or antibiotic use, reducing density, and placing columns of artificial seaweed in net pens as refuge for lumpsuckers for sea lice control. The former CEO of Aquabounty, Elliot Entis, thinks all salmon farming should be done on land. He extolled the benefits of the GMO salmon developed by the company, including growth to market size in half the time, 25 percent improvement in feed conversion, and greater ability to use plant-based feeds.

In one of the more interesting points raised by the film, Greenberg uses salmon as an example of how aquaculture can increase the demand for wild fish by selling more farmed fish, running counter to the common narrative that aquaculture can take pressure off of wild stocks. He cites what happened to the Alaskan salmon industry, which was battered by competition from farmed salmon in the early 2000s but changed and adapted. Salmon that were once canned are now processed into fillets. Alaska also ramped up smolt releases so now one in three salmon come from hatcheries. The Alaska industry is back and demand for wild salmon is as high as ever.

In general, the documentary presents the issue of consumer choice and the role of aquaculture with appropriate subtlety and discrimination. Greenberg urges viewers not to focus on comparing wild with farmed fish but on comparing fish protein to other forms of protein. He clearly affirms that meeting protein needs through aquaculture is better for our personal health and the planet than eating more beef, pork or poultry.

The documentary was also valuable for the way it distinguished different forms of aquaculture, a message that is often lost in media coverage of aquaculture. Greenberg extolled the virtues of extractive aquaculture in a segment on kelp and mussel farming, recommending that consumers start by choosing bivalves and other “zero-input foods” that “make the sea better while they feed us.” Greenberg advocates for forms of aquaculture that contribute to a net gain in the global fish supply.

After a year of eating fish, Greenberg’s proportion of omega-3 fatty acid content was about 10 percent, or twice that of the average American. However, his blood pressure, triglyceride level, cholesterol level, and ratio of good to bad cholesterol were unchanged. Associated with his diet, Greenberg had elevated mercury levels that likely canceled out any benefit of omega-3 consumption. These unexpected results left Greenberg with a sense of uncertainty and surprise. In the end, his message was one of moderation and balance, of farming and fishing, of eating those farmed fish that are better for the planet, and of eating fish regularly but not every day.

Implicit in the piece was the idea that future supplies of fish to feed an expanding global population will come from the oceans. No doubt extractive mariculture will play an important role in getting food from the sea, but it is difficult to see how expansion of the marine finfish sector can proceed widely and to a scale that will contribute significantly to the global supply of foodfish. Greenberg’s piece ignores the role of freshwater aquaculture in providing the majority of future foodfish supplies, thereby relieving some pressure on the oceans. Nonetheless, Greenberg’s uncertainty and equivocation were valuable in presenting a complex subject to the public.