Marks Daily Apple
Serving up health and fitness insights (daily, of course) with a side of irreverence.
11 May

Farmed Seafood: What’s Safe and Nutritious

Learning about the various types of aquaculture setups is interesting and useful, but we’re ultimately interested in whether they can produce safe, nutritious, affordable seafood. Wild seafood can be pricey, unavailable, and of questionable merit or sustainability. Certain wild species are definitely worth pursuing – Alaskan salmon, sardines, herring, mackerel, to name a few – but there are environmental (overfishing, collateral damage to other important species, structural damage to the marine environment) and health (accumulation of heavy metals like lead and mercury, polychlorinated biphenyl/PCB, dioxin) issues that the conscious fish eater must stay abreast of. Healthy and safe farmed seafood, then, would be a welcome alternative, if it’s out there.

Okay. Let’s get down to it.

Which farmed seafood is safe to eat? Is there anything like grass-fed beef or pastured chicken available in scales or shells?


As a whole, farmed shellfish, when compared to wild shellfish, are very good bets for the simple fact that both lead very similar lives. Every marine shellfish, whether farmed or wild, spends its life in the ocean attached to something – rocks, a rope, a pillar, coral, the ocean floor. The only difference is that farmed shellfish are deliberately placed there by farmers, while wild shellfish are distributed by the hand of Poseidon (actually, the Nereids do all the work while he gets the credit, but such is the life of a sea nymph). Most importantly, they all use the same sea water. They all obtain their food by sifting through that same sea water. Farmers don’t have to provide food. They’re not scattering corn and soy across the water, because it would be a waste. Shellfish, you see, are filter feeders.

That brings me to the primary concern people have with shellfish, or mollusks. “Filter feeder” just sounds bad. When we hear the phrase, we think of physical filters, the type we use in everyday life, like an air filter in a car engine or a coffee filter. Physical filters accumulate the undesirable stuff and are either cleaned, tossed, or recycled. They certainly aren’t eaten. Well, shellfish aren’t physical filters. They process toxins. They render harmful compounds inert and expel them. It’s true that if they reside in waters rich in heavy metals and industrial contaminants (like PCB or dioxins), some of those metals and contaminants will show up in the meat, but that’s true for any sea creature. In fact, shellfish are some of the safest, least contaminated farmed seafood whenever they’re tested.

They’re also extremely nutritious. Shellfish are extremely rich in vitamins and minerals. Three measly ounces of raw Pacific oyster (the bulk of which are farmed) gets you over 100% of the RDA for zinc, copper, selenium, B12, and half of the RDA for iron. For every 1.5 g of omega-3 they provide, just 0.1 g of omega-6 comes along for the ride. Bay scallops are high in magnesium and selenium, clams are good for iron, copper, and selenium, abalone for selenium and magnesium, while the lowly sea snail gives massive amounts of magnesium (200 g of snail gives over 500 mg of magnesium; maybe they’re counting the shell?) and good amounts of selenium.

Lately, a favorite of mine has been the green-lipped mussel, shipped frozen from New Zealand. I initially got interested in this particular variety because of the research into green-lipped mussel extract as a canine arthritis treatment. Buddha isn’t arthritic, but I find this stuff fascinating. I’ve had some arthritis in the past, and it never hurts to cover all your bases ahead of time. Besides, mussels are delicious and nutritious. The NZ green-lipped mussel gets good marks from the Monterey Bay Aquarium Seafood Watch, owing to its farmers’ sustainable practices: attach young mussels to ropes, lower the ropes into the ocean, and let nature take its course. I was also surprised to see the amount of omega-3s in these things. According to one study, 100 g of them (flesh only, no shells, frozen) comes with 1.5 g of DHA, 1.26 g of EPA, and not even half a gram of omega-6 fats.

Farmed shellfish are safe and just as nutritious as wild. If you’re worried about contamination, check the source and do some research. Always buy still living shellfish (dedicated seafood markets or Asian grocers are great places to buy live shellfish) where you can. If frozen is available, check the label and avoid imports from China, where waters are more likely to be heavily polluted.

American Catfish

The channel catfish is a bottom feeder, which sounds bad but doesn’t have to be. They’re just rapacious eaters, or foodies, even – a bit like hogs. If you feed them garbage and raise them in polluted waters (like occurs in Chinese catfish farms – check your labels!), you can’t really blame the species.

Farmed catfish is far fattier than wild catfish while being lower in omega-3s, but catfish has never been prized for its omega-3 content. While farmed catfish does have more omega-6 than wild – about 1.5g for every 100 g fillet, compared to around 0.22 g – most of the “added” fat in farmed is monounsaturated (5.7 g/100 g) and saturated (2.5 g/100 g) (PDF). Not too bad, especially if you compare it to something like conventional skin-on chicken thigh, which gives you 4 g saturated fat, 6 g monounsaturated fat, and 3 g omega-6s for a 100 g serving. US catfish farmers may not be feeding their fish pristine, natural diets of bottom-dwelling crustaceans, insects, and small fish, instead opting for combinations of meat and bonemeal, bloodmeal, fishmeal, various seedmeals, corn, soy, wheat byproducts, and vitamin/mineral supplements, but catfish seem to turn out decent fatty-acid profiles despite the departure from ancestral tradition (PDF).

Toxin-wise, catfish farmed in the US are subject to strict standards and, according to a 2008 study, has very low levels of methyl-mercury and industrial contaminants like PCBs and dioxins. You may want to avoid the abdominal fat deposits on farmed catfish, however, as they contained somewhat elevated levels of dioxins. (PDF) Other studies have shown conflicting results when comparing toxins levels in wild-caught and farm-raised US catfish, with some showing similar toxin levels (PDF) and others showing big disparities in favor of farm-raised. Either way, the toxins involved are at low enough concentrations not to cause worry, and they “appear to be dropping” in recent years.

If you like catfish, eat American farm-raised. It’s known for being a pretty bland fish (well known for deep frying in cornmeal batter and as a vehicle for sauces), but if it’s on the menu and you feel like fish… why not?

Tank-Farmed Freshwater Coho Salmon

Yes, that’s right. There is a decent farmed salmon: coho salmon raised in freshwater tanks. It’s not as magnificent as ruby-red firm-fleshed wild Alaskan sockeye, but it is low in omega-6s, fairly high in omega-3s, gets a “Best Choice” rating and makes “The Super Green List” (good for the environment, low in PCB and mercury, high in omega-3s) from the Monterey Bay Aquarium Seafood Watch, and spends its life in carefully monitored freshwater tanks (as opposed to tightly packed coastal nets where metals and contaminants like dioxins and PCBs accumulate). The biggest health problems with farmed (Atlantic) salmon are the increased levels of omega-6 and the high levels of environmental and industrial contaminants. Freshwater farmed coho salmon avoids both. According to several sources, farmed coho salmon (and this is the regular, coastal farmed stuff, not the quality freshwater tank coho) sports a high omega-3:omega-6 ratio. A recent study (PDF) found that a 100 g portion of raw farmed coho contained 1.42 g omega-3 and just 0.46 g omega-6 (ratio of 3.1:1), compared to wild coho’s 0.9 g omega-3 and 0.06 g omega-6 (ratio of 14:1). The ratio is way different, sure, but does it really matter, given the paltry absolute amount of omega-6? If you look at the USDA database, 100 g of raw farmed coho has 1.3 g of omega-3 and 0.3 g omega-6. Any way you cut it, farmed coho is a good source of essential fatty acids, and I’d guess that freshwater tank-farmed coho salmon is just as good as conventionally farmed coho in that regard, if not better.

As of now, there are only a few freshwater, landlocked coho salmon farms in operation: Domsea Farms, out of Washington state, which sells coho to Whole Foods and other retailers under the SweetSpring label; and Swift Aquaculture, in British Columbia, which supplies upscale restaurants. More are surely coming, though, so be on the lookout for tank-raised (not coastal) coho in your area. You’ll still want to avoid other farmed salmon, of course.

US Rainbow Trout

Most rainbow trout eaten in the United States is also farmed there, and it’s one of the better choices. It may not be a sexy, exotic fish with intense flavors and high levels of omega-3s, but it’s a solid choice with a low environmental impact, minimal levels of contaminants, and a reasonable price. You can get it fresh pretty much anywhere and know, just by the “Farmed, USA” label, that it’s safe to eat.

More so than any other farmed fish I’ve come across, the fatty acid profile of farmed trout closely resembles that of wild trout. For example, a single 100 gram fillet of farmed rainbow trout has a gram of omega-3, 0.7 g of omega-6, 150% of the B12 RDA, and a decent amount of selenium. The same amount of wild trout is extremely similar nutritionally, with the main changes being 200 mg fewer omega-3s and 500 mg fewer omega-6s.

Farmed trout is very low in environmental contaminants. Methyl-mercury levels are well within the acceptable range (PDF). The same seems to hold true for Canadian trout, too.

US Barramundi

A tropical white fish, the barramundi is the “it” fish of the moment. It’s low in overall fat, offers about 840 mg of omega-3 per 5 ounce serving, requires less wild fishmeal than other carnivorous fish, is relatively free of contaminants, lives in freshwater tanks (at least in the United States) where it can’t affect wild ocean stocks, and Dr. Oz sings its praises (which almost makes me want to delete this section). Barramundi is okay, I guess, but it sounds rather uninteresting and bland. It’s also expensive, fetching over ten dollars a pound for frozen fillets at some markets.

Still skeptical? Listen to the barramundi evangelist talk about the fish on NPR for an unbiased perspective. No, but seriously – by all accounts, it’s a safe farmed seafood choice with nice levels of omega-3s, so give it a shot. Or, at least, don’t fear the barramundi.

American Crayfish

These are freshwater crustaceans and thus not seafood, but I spent many a summer catching them in New England, so I’m going to include them anyway. Crayfish are great, like tiny lobsters. Crayfish farming gets a clean bill from the Monterey Bay Aquarium, and I like that crayfish farming often means setting the little mudbugs loose in a rice paddy or pond to feed on the local flora and fauna, enrich the local habitat, and breed like mad. Farmers will sometimes supplement with feed pellets, but not always. Not a lot of meat on them, but if fully cooked they can be entirely consumed, shell and all. If you’re too squeamish to do that, you should definitely suck out the sweet contents of the head and eat the tail.

Look – if Trapper Arne’s awesome 1990s-era website says that “crayfish is good eating,” I’m not going to argue. Stay away from imported crayfish from Asia, though; stick to farmed crayfish from the United States.

What say you? Have I gone mad? Is all farmed seafood poisonous and toxic? Have I left out your favorites? Let me hear about it.

You want comments? We got comments:

Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

  1. Walmart sells bags of frozen Tilapia fillets from Hawaii that include Carbon Monoxide(yikes!) as an ingedient, so I don’t touch those. What the freak? Am not a big fish fan yet but am trying to learn to like it more. Gonna try buffalo sauce on sardines!

    Keet wrote on May 12th, 2011
  2. Walmart sells bags of frozen Tilapia fillets from Hawaii that include Carbon Monoxide(yikes!) as an ingedient, so I don’t touch those. What the freak? Am not a big fish fan yet but am trying to learn to like it more. Gonna try sardines in buffalo sauce! I do love raw oysters so was happy to get the go ahead on those, thanks.

    Keet wrote on May 12th, 2011
  3. I definitely think there needs to be a continuation to part 2 about this. :)

    Kevin wrote on May 12th, 2011
  4. This post is very interesting indeed. I agree that the “farmed” bivalves are a good choice because they are grown in natural habitat eating the same things that the wild ones do. But the farm raised fin-fish are definitely questionable. The finfish are given soy, wheat, corn, supplements, etc… I’m not convinced that they are good. BUT, I know the wild stocks are in danger of being overfished. It’s truely are fine line we are walking. What to do?!

    Dennis wrote on May 12th, 2011
  5. Hmmm. Interesting post Mark. I am feeling very eeek about wild fish myself lately due to concerns about contamination and I had previously thought the farm raised fish were perhaps not as nutritious but now I see that may not be true.

    I have read a few articles about the problems with pollution from fish farms being generated by all the fish poop as well as farmed fish who escape their pens wreaking havoc on the wild species. Eating sure is getting to be a complicated issue.

    A couple of people asked about shrimp, Food and Water Watch has done a rather lengthy article here on farmed shrimp, they suggest sticking to domestic varieties.

    Denise wrote on May 13th, 2011
  6. Traditionally, monks used to raise carp for food in ponds. I have heard that they don’t have a great taste, but it gets better if you put them in a separate fresh water tank without food for a few days to clear out their systems.

    P.M.Lawrence wrote on May 14th, 2011
    • They have a vein that runs through their meat that the old timers around the Kaskaskia River in Illinois referred to as a “mud vein”. If you cut it out, carp is just like catfish: white, flaky and devoid of much flavor.

      The nuisance fish gar are also edible, but they require a more nuanced method of cleaning, or they are too foul to stomach.
      Basically, they also have the “mud vein” and they MUST be drained of ALL blood ASAP when cleaning them. Oven roasted, they are also quite tasty.

      Keith wrote on May 14th, 2011
  7. I do have a minor point of contention about your catfish description. The channel, blue and flathead catfish are most definitely NOT bottom feeders. They are predatory in the same way as the bass and perch family. They will occassionally scavenge for food if hungry, but by and large they eat live prey.

    The varieties of bullheads (brown, black and yellow) are far more accurately described as bottom feeders.

    Keith wrote on May 14th, 2011
  8. Do you plant them head up or head down? And how do you fertilize them? lol!

    Couldn’t resist..Old Texas Aggie joke.. the answer is send soil sample.

    Reloader wrote on May 14th, 2011
  9. I don’t know if they are still up and running but we have had pond-raised shrimp from the grower in this link. They can grow 7-count shrimp in a single season. I personally can’t tell the difference in flavor and at the time we were there they were selling them individually blast-frozen so they were easy to handle.

    We knew Coddington personally. His background was as an aquaculturist at Auburn University and he has traveled around the world teaching/learning technique.

    Alfred wrote on May 14th, 2011
  10. This is really great news! My family and I are big seafood consumers and searching for wild all the time has really become difficult and costly. Good to know there are still decent farmed alternatives :)

    Not directly related, but what about the quality of frog legs, squid, octopus, quail imported from overseas? In my local Asian market there is a lot of exotic meats but as always I worry about the conditions they’re raised, plus contamination…

    Mammoth toppler wrote on May 15th, 2011
  11. I totally have to disagree with the statement that Barramundi is bland. Chargrilled with even a basical lemon and EVOO rub, Barramundi is delicious. When rubbed with a more interesting or primal rub, it turns into something out of this world. I live in Australia so the freshness of the fish may have something to do with it, but out here you cant go into a restaurant without seeing a Barra dish.

    Glenn wrote on May 15th, 2011
  12. I was under the impression that farm raised fish is usually bad for the environment. I thought it takes more to grow the fish than the fish can give back.??

    Paleo Josh wrote on May 17th, 2011
  13. Just found your website and love all the information you provide about fish! Have you ever heard of Clean Fish? I recently bought some from the plum market in ann arbor mi and thought it was a little fatty but I would be interested in your opinion of this company.

    thehealthyapron wrote on May 18th, 2011
  14. ps. cleanfish is a company

    thehealthyapron wrote on May 18th, 2011
  15. Green lipped mussels are delicious, they are cheap and fresh at our supermarket every day.

    You might be interested in this post I have just done – charts of omega 3 and 6 in oils, fats, meat and seafood.

    ********i have to add. yeah i like them too. sadly the farming also has a big eco effect. and even kills mamals like smal whales. This report of Mark is to positive and the negative effects are too much on health facts. From Germany i can suggest either its labelled certified organic or be very cautious on everything. The chemicals used in seafarms are really harmful weather makr like it or not, and toxic effects shows over decades. So also if people go well on this farmed toxic fish and seafood over decade they can develope miscariages and illnes.

    For Animals farms and also for animal fishfarm look how the fish is raised. Dont go for data. Dont go for science. Go for how it looks. If it looks animal friendly environmental ok. Its probably good. The safest thing is fresh. go to the producer go to the farmer and if they wanna hide something or come up with too much scinctificfacts its probably something stinky and mold.

    If you avoid all antibiotics in your normal diet, be sure to get them in normal farmed seafood. Thats sure.

    fruit wrote on May 18th, 2011
  16. Dont trust marks words. In my experience this topic is more complex. scientific research is bought by fish farm companies. This is a hard topic to get a clue on. Have look how the fish is produced. And what are the effects on the ecosystems and on wildlife. Any other data can be fake. Only dead animals or dying plants or stinky water are real indicators for not working or for working farms. Beside i suggest look for certified organic farms. That is a rather safe choice. And that is defintly true.

    fruit wrote on May 18th, 2011
  17. One big eco problem with fish farming is: The farmed fish needs food and this is made by small fishes and fish waste. Which are caught in often worse conditions. This threaten the wildlife diversity and the ecosystem.

    The food of the farmed fish is usually fish. This fish is often caught in big scale so it wipes out whole ecosystems. There are different ecoviews on fish farming. Only very rare are ecofriendly. This one try hard to be ecofriendly. Just think on stinking water places where fish is swimming close to each and foam is there from food chemicals and antibiotics. Pangasius(noz organic) is one of the worst conditions. You will surive it. Pangasius taste mold and the fish swimms in mold water. the companies in asia try to hide it.

    Do you not think they wanna test all the chemicals they develope over the years. yeah they wannt and they do it on animals. It more than meat and protein, its a living being and feel good in healthy wildlife.

    cloudwind wrote on May 18th, 2011
  18. I’m so glad I live in New Zealand. Some of the best seafood ever!

    Shirley wrote on May 18th, 2011
  19. The biggest problem I have with farm raised fish, is man’s greed again into farming for maximum profits. While they throw the guise of it being “more natural and healthy” and better for the environment, this, for the most part, couldn’t be further from the truth. In order to feed so many of these “farm raised fish”, the are raping the oceans of the natural bait fish and food for the wild fish. They fatten them up as quickly as possible, and therefore the farmed fish are eating many many more tons of wild caught bait-fish than there natural or wild counterparts would. Thus the environmental impacts are quite substantial. Please do your homework and then read the labels and don’t support these particular types of farms.

    ShellO wrote on May 23rd, 2011
  20. I’m very late to this post but just wanted to add that Walter Crinnion, N.D., who has made environmental toxins his specialty, says tilapia and trout are the 2 farmed-raised fish that are consistently low in toxins (mercury, PCB, etc). Sardines, even when fished, are very high in PCBS as are catfish, even American farmed. (, but info came from 2012 workshop)

    SueZ wrote on August 10th, 2012

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