Seafood is good for you. That’s no surprise. But it’s not easy to find species that don’t contain mercury, PCBs, PFAS, or other contaminants, aren’t overfished, and aren’t linked to human rights abuses. In her new book The Fish Counter, NYU professor emerita Marion Nestle tackles those and other issues. (The book goes on sale on June 6, but you can pre-order it now.) 

Marion Nestle is the Paulette Goddard Professor of Nutrition, Food Studies, and Public Health, Emerita, at New York University and the author of 16 books, including Food Politics  and Safe Food. She’s also the author of the popular website, foodpolitics.com. Nestle spoke with Nutrition Action’s  Bonnie Liebman. 

 What led you to write The Fish Counter?

MN: When I wrote What to Eat  in 2006, there were more chapters devoted to fish than to any other topic. Who knew that it was that complicated?

You go to a fish store, you pick the one you want, you take it home, you cook it. You think you’re done, but if you start asking questions, you can’t buy anything. There are so many almost unsolvable issues.

Like whether to buy farmed or wild-caught fish?

MN: Yes. The reason for farming is that the ocean has been overfished in dreadful ways—like using explosives or by dragging mile-long nets through the water. The fish don’t have a chance. So ocean fish are enormously depleted.

You call it an extraction industry.

MN: Yes. Countries can only control their own fishing waters, and everyone wants to extract as much fish as they can. So it’s become increasingly mechanized. Often it’s done with explosives like dynamite.

What are they exploding?

MN: They set off an explosion near the ocean bottom, and the fish rise to the surface. It’s absolutely awful.

Also, the fish are sometimes tracked by radar. The nets are miles long, so there’s phenomenal waste because they bring up all kinds of fish that aren’t sellable. So they throw them back, dead or alive. 

And 70 to 85 percent of seafood sold in the US is imported?

MN: Yes, and you have no idea from where because wild-caught fish can be labeled as caught in the US, for example, as long as the fishing vessel has a US flag, regardless of where the fish were actually caught. 

Are there human rights abuses on fishing vessels?

MN: It’s hard to monitor because some are far out to sea for weeks or months. With no one watching, operators can starve, punish, or even murder their workers with impunity.

Some fishing vessels have observers to look for environmental violations. But nobody wants the observers to see anything, and they’re subject to a surprising number of accidents. Uh-oh, man overboard.

It’s very dangerous work—so dangerous that the organization that represents observers on fishing vessels is extremely worried about the risks. You’re out at sea, there’s nobody watching, and you have no escape.

Tuna may be good for you, but in March, four Indonesian fishermen filed a lawsuit accusing Bumble Bee (owned by FCF, a Taiwanese company) of benefiting from the forced labor and abuse the men suffered.

Does fish farming have problems?

MN: Farming fish can be done well or it can be done terribly. Better farms minimize the use of antibiotics and pesticides and keep chemicals from being discharged into nearby waters or land, and they don’t deplete ocean stocks to feed farmed fish. That’s easier to avoid doing if you’re farming seafood that’s lower on the food chain—like shellfish, catfish, or tilapia—rather than fish like salmon that eat other fish or require sources of omega-3 fats.

Are inland farms better or worse?

MN: It depends. With inland fish farms, it’s easier to set up systems to handle the waste. With fish farms in the ocean, uneaten food pellets and fish waste can pollute the water and harm plants and animals living on the sea floor. Managing that is difficult when you’re dependent on tides.

I visited some Norwegian ocean fish farms, and they’ve got 80,000 fish in one of these pens, swimming around in circles, and they throw the feed in. The feed drops. The fish eat it. If the fish don’t eat it, it gets out of the pen. 

Is farmed salmon naturally gray?

MN: Yes. It’s dyed salmon color with astaxanthin, a safe dye. You can buy it as an antioxidant supplement, though evidence for its benefits is weak.

But nobody eats gray fish unless they expect it to be gray. They’ve done studies that show that the brighter the red color, the more people like it.

Is most shrimp farmed?

NM: Yes. Much of it comes from Asia, where it’s farmed in polluted water. Many shrimp farmers use massive amounts of antibiotics, disinfectants, and pesticides. None are good for your health, and none are strictly necessary. And using antibiotics could create resistant bacteria.

What about microplastics?

MN: Much of the plastic in the ocean ends up in what’s called the Great Pacific Garbage Patch. A lot comes from fishing vessels. Some of the plastic gets beaten up by the ocean, so you get tiny pieces that are too small to see. We don’t know what ingesting them is doing to us, but it can’t be good. Of course, microplastics are in our air, water, and other foods, not just in fish.

Where does mercury come from?

MN: One source is underwater volcanoes. We can’t do anything about that. Another is coal-burning power plants, about which you can do a great deal. You can insist that the power plants clean their emissions.

For decades, presidents have wanted to stop coal-burning power plants from emitting mercury, and under President Biden, the EPA limited emissions. Now the EPA is planning to roll back those controls. 

How does mercury get into fish?

MN: It’s very heavy, so any mercury in the atmosphere falls to the ground, then eventually washes into the ocean. And if mercury gets methylated, it’s extremely toxic.

The classic example is a truly shocking incident that happened in Japan. Between 1932 and 1968, a manufacturing plant dumped methylmercury into the bay around Minamata at enormous levels. The fish picked it up, and people ate the fish. Methylmercury is toxic to the developing nervous system, so kids were born with severe neurological disorders like deformed spines and intellectual disabilities.

The plant knew about it, the government knew about it, but nobody did anything because of corruption and because if they had, the fishermen wouldn’t have been able to catch as many fish. In the meantime, thousands of kids suffered.

What about lower doses of mercury?

MN: There have been instances of people who eat a lot of albacore tuna showing neurological symptoms.

But only the large predatory fish are a problem, because methylmercury moves up the food chain. Little fish eat it, and then big fish eat the little fish, and bigger fish eat those fish, so it accumulates in their muscle.

Which fish are high in mercury?

MN: Shark, swordfish, king mackerel, tilefish from the Gulf of Mexico, marlin, orange roughy, and bigeye tuna. Most people don’t eat them often, but they do eat albacore tuna, which has about half the amount in other big predatory fish. That’s still a lot.

The tuna industry has fought any attempt to tell people to eat less albacore. Fortunately, light tuna has less mercury, and it’s cheaper. [See cspinet.org/mercury for more.]

What about fish you catch yourself?

MN: If you’re a sports fisherman fishing in US inland waters, many state advisories say you can’t eat any—or very much—of the fish you catch because of the PCBs, PFAS, or mercury. That’s astonishing to me.

Are fish often mislabeled?

MN: I don’t know about you, but when I go to a fish market, many fish look pretty much alike to me. Labels are supposed to say what they are and where they come from. But unless you trust your fish seller, be suspicious.

Salmon is the best example, because retailers can get so much more for wild salmon than they can for farmed salmon. They may also mislabel cheaper fish as more expensive lemon sole, red snapper, or grouper.

Do we need the omega-3 fats in fish?

MN: High-dose omega-3 supplements reduce triglyceride levels, but when it comes to reducing heart disease risk, some studies find a reduction while others don’t. So I’m not convinced that the omega-3s in fish are essential.

Nevertheless, based on research suggesting that omega-3 fats might prevent blood clots and the irregular heartbeats that can lead to heart attacks or strokes, the American Heart Association recommends two servings a week of fish, especially fish rich in omega-3s like sardines or salmon.

Is there a single place where people can go for advice about fish?

MN: No one deals with everything. The Monterey Bay Aquarium’s Seafood Watch, which is the best of the lot, deals largely with sustainability. It doesn’t deal with toxins. The FDA deals with toxins. It doesn’t deal with sustainability.

The Global Seafood Alliance issues seals for Best Seafood Practices and Best Aquaculture Practices. It has standards for managing fisheries and the rights and welfare of crew members. You can look for “BSP certified” or “BAP certified” when you shop.

And all the wild-caught fish at Whole Foods is either on Seafood Watch’s Best Choice or Good Alternative list or has been certified by the Marine Stewardship Council. Whole Foods also has standards for farm-raised fish.

What’s your take-home message?

MN: We should look for every conceivable way to stop polluting and overfishing. These are huge problems.

But in the rest of the world, loads of people are absolutely dependent on catching fish in the ocean to survive. It’s pretty tough to say we want them to stop, but we certainly want them to do it without destroying so much.