What happens if you eat fish every day for an entire year? Paul Greenberg, the environmental journalist, fish fanatic and author of the bestseller Four Fish, set out to to find out. In the new PBS Frontline documentary The Fish on My Plate, Greenberg explores the implications of consuming seafood for both our own health and the health of our planet. The film opens with Greenberg speaking to an audience in Sitka, Alaska, explaining: “For the last year, I’ve been eating seafood every single day. Sometimes for breakfast, lunch, and dinner, and a snack.”

In the hour and a half documentary, Greenberg takes us on a journey to Peru, Norway, Alaska, and then finally to New York City, exploring all the different ways that seafood of many varieties makes its way from the water into our supermarkets, refrigerators, and ultimately our stomachs. In an interview with Frontline, Greenberg explained that once he moved away from “land-based animals,” he discovered the depth of diversity to be found in the seafood department:

Previously, you'd go into the supermarket and you’re like, 'Huh what’s for dinner tonight? Is it going to be the red steak or the white chicken?' But when you cut all of that away, when the meat department is no longer a purview, you go to the seafood counter or to the frozen section, and you realize there’s actually quite a large selection and that you can have variety in your life. If you don’t just think about it as fish, but as, 'Oh, I could have mussels, I could have salmon, I could have tilapia, I could have haddock,' those flavors tend to enunciate themselves once you’ve fine-tuned yourself. When you really engage in a big way, you develop a better appreciation of the subtleties of seafood.

The year-long quest to explore the bounty of the oceans left Greenberg’s Instagram jam-packed with seafood porn, recipes, and purchasing advice.


Greenberg is far from alone in his increased consumption of seafood; more people are consuming more fish than ever before. According to the United Nations Food and Agriculture Organization, global annual per capita consumption of seafood rose to almost 45 pounds in 2016, the highest number ever recorded. This massive consumption of seafood comes at a cost though. According to the United Nations agency's State of World Fisheries and Aquaculture, almost a third of all commercial fish stocks are currently fished at unsustainable levels, triple the level of the 1970s. By some estimates, stocks of many large oceangoing fish like bluefin tuna and swordfish, and many species of sharks, have been reduced by up to 90% over the past few decades. Greenberg confronts these issues face on, attempting to answer the critical question of how the ocean can feed a growing and hungry planet.

One of the more striking places that Greenberg visits is Peru’s anchoveta fishery, which produces more pounds of catch per year than all of the fisheries in the U.S. combined. Greenberg speaks to Patricia Maljuf, the vice president of Oceana Peru, who explains that despite anchovies being nutritious fish, high in omega-3 fatty acids, almost none of the fish caught in Peru are consumed by humans. Instead, 99% of the catch is ground up and dried to be turned into fertilizer for crops and feed for animal and fish farms. Peru’s anchoveta fishery is not alone here, with about 25% of all fisheries across the world functioning as “reduction” fisheries.


Greenberg explains that about 50% of all fish consumed worldwide comes from fish farms, which is both good and bad. On the one hand, increased consumption of aquaculture reduces the stress on wild fisheries. But if mismanaged, aquaculture can lead to a whole slew of environmental impacts that counteract these benefits, including: pollution of waterways from concentrated fish droppings; diseases and parasites, such as sea lice; inefficient feed conversion ratios (the amount of feed eaten by a fish compared to the amount the fish provides for human consumption), all of which create stress on wild fish stocks, like Peru’s anchovetas.

Some of the most egregious environmental transgressions of aquaculture are committed by salmon farms. As the demand for salmon grew and grew, salmon farms aimed to increase yields, often regardless of the environmental impact. Salmon farms have been guilty of contaminating waterways with organic and inorganic waste, widespread infestations of sea lice, and farmed salmon escaping into the wild where they could negatively impact wild salmon populations. The result is that while salmon farming has earned a reputation for not being very environmental friendly, it has also become the most widely consumed farmed finfish in the world.


Aquaculture can be sustainable

Still, Greenberg explains that done right, aquaculture can be a sustainable way to feed the 7.5 billion people on our planet. Greenberg pays a visit to Bren Smith, the director GreenWave farms, an ocean farm that is revolutionizing the way we grow our food. GreenWave uses a model known as 3D Ocean Farming to cultivate seafood in vertical columns in the water: seaweed, mussels and scallops grow at the top, on floating ropes, below are oysters cultivated in cages, and then below that hang cages of clams. The entire system is cheap, efficient, and requires very little actual space. Far from polluting the water, the shellfish clean up the ocean by soaking up nitrogen, phosphorous, and carbon, and the seaweed soaks up carbon and requires zero inputs in terms of fresh water or fertilizer.

“Industrial aquaculture went exactly the wrong way in its first stages,” explains Smith. “We were really running Iowa pig farms in the ocean. So what we’re trying to do is learn from those mistakes and really do food right.”


Greenberg goes on to explore other fisheries and aquaculture operations in his attempt to discover what the future of seafood looks like. Another likely candidate that Greenberg highlights is Blue Circle Foods, a salmon farm in northern Norway. By raising a limited number of fish in pens and feeding them scraps of processed fish (rather than fish feed sourced from wild fish), the farm is trying to re-imagine what salmon farming can look like. Fittingly, Greenberg then travels to Alaska, to explore the last wild salmon fishery. Through a comprehensive and ever evolving management program Alaska has been able to keep the last wild salmon fishery sustainable and profitable for the last 150 years. The conclusion for Greenberg is that while aquaculture and ocean farming are critical for feeding a growing planet, that doesn’t mean that wild fisheries should be underappreciated or forgoteen; the balance of properly managed wild fisheries and environmentally friendly aquaculture are the future of seafood.

Do fish make a body good?

And what of Greenberg’s own health, after eating seafood for an entire year? Surprisingly not much seems to have changed. A visit to the doctor shows that any gains that Greenberg made in terms of higher levels of omega-3s (which are touted as being beneficial for cognition and heart disease) were likely offset by slightly elevated levels of mercury. Greenberg ends his yearlong seafood adventure by having a burger, explaining through mouthfuls: “No omega-3s. I mean, it’s wrong, completely wrong for the planet and don’t try this at home, but let’s just say if you have 700 odd fish meals in a year, then you deserve one burger.”


The full documentary is available for free on Frontline's website.