Confused about which fish and shellfish are the best choices when it comes to your health (and the environment)? Start here with our tips on how to choose safer seafood.
Eat more fish.
That’s what the U.S. Dietary Guidelines preach for all Americans and we’re onboard with this recommendation as well because seafood (fish and shellfish) is:
- A great source of high-quality protein.
- A tasty alternative to chicken, beef, and pork to change up the menu.
You also get a healthy dose of omega-3 fats when you choose cold water varieties like salmon, tuna, trout, and sardines, which has been shown to decrease the risk of cardiovascular disease and Alzheimer’s – and may boost your mood too. The current recommendation is to consume 12-18 ounces, or 2-3 servings, of lower-mercury seafood per week for optimal health benefits. This includes salmon, cod, canned light tuna, tilapia, scallops, mussels, shrimp, pollock, and crab.
That being said, there is a lot of information out there about which fish and shellfish are the safest and most ecological options. So much information, in fact, that you may have thrown your hands up in the air and just overlooked seafood as a healthy option which is why we’re talking today about how to choose safer seafood.
We’ll share just about everything you need to know to make you a savvy consumer of seafood including how much to eat each week, the risks of mercury and how to choose lower-mercury seafood, how to choose the freshest seafood and we’ll even take a quick dive into which species to limit or avoid from an environmental health perspective. Though we’ve tried to keep this post as short as possible, there’s a lot of information so if you just want the ‘quick download’ on how to choose safer seafood, then scroll down to find the list of our Top 8 Safer Seafood Picks below.
Health – yours and that of the environment.
When we’re talking about “safer” seafood we’re really talking about two things – mercury (your health) and sustainable fishing practices (the environment). Unfortunately, all seafood choices don’t fit into one tidy category or another. While some are pretty black and white, say swordfish, there are others like tuna and flounder that fall into the grey area between so we’ve done our best to present information about both issues to help you choose the best options for you and your family.
What is mercury?
Mercury can be found in small amounts in air, food, and water and in higher amounts in amalgam dental fillings. Most foods are considered to be extremely low in mercury with the exception of fish and shellfish, which can contain considerable amounts of mercury in its most toxic form, methylmercury.
Methylmercury is created when mercury circulating in the environment is dissolved in waterways (freshwater lakes and rivers and saltwater oceans). This mercury then accumulates in the flesh of fish and seafood, concentrating as you move higher up the food chain (i.e. predatory fish eating smaller fish, older or larger fish, etc.).
Methylmercury is highly toxic and seafood is the largest contributor of mercury in humans. Because its effects are dose-dependent and the toxic dose varies depending on age (young children are at higher risk than adults), life stage (pregnancy and/or breastfeeding), and body weight (the lighter you are, the less you can handle) the recommendations as to how much is safe to consume will vary. During pregnancy, methylmercury exposure, even if not at a toxic level, can increase the risk of stillbirth and/or birth defects because it easily crosses the blood-brain barrier and placenta, which is why it’s particularly important to understand how to choose the lowest mercury seafood so you can still enjoy the health benefits while significantly lowering your risk of toxicity.
For most people, the health benefits of consuming fish outweigh risks of mercury, but there are things you can do to decrease or minimize your risk.
- Eat lower on the food chain: Mercury accumulates in larger, older fish and too much mercury exposure can lead to fatigue and difficulty concentrating (with consistently low-level exposure) or numbness or tingling of the hands or feet and impaired brain development in fetuses, infants and young children with higher exposure thus the need to seek out lower-mercury fish.
- Big fish to avoid: Shark, tilefish, king mackerel, bluefin and ahi tuna, swordfish, Atlantic flatfish such as halibut, flounder and sole. All of these are high in mercury and some, like shark and tuna, are overfished.
- Limit your intake:
- For non-pregnant adults: Eat up to 18 ounces (3 servings) per week of low-mercury fish and seafood.
- For pregnant or breastfeeding women and children: Eat up to 12 ounces a week (2 servings) of canned light tuna and other low-mercury fish, such as salmon, shrimp, catfish, pollock, and scallops. Within this 12 ounce allowance:
- Limit your intake of fresh or canned albacore (white) tuna to 6 ounces per week.
- Limit your intake of locally caught lake or river fish to 6 ounces per week. You can find out about the safety of locally caught fish in your area here.
Given how toxic excess methylmercury exposure can be, our suggestion is, first and foremost, to choose fish and shellfish for its health benefits (or more accurately in this case, for its reduced risks), but along with that we also recognize that the sustainability of the fish and shellfish also has a big impact on the environment.
What are the environmental concerns?
Oh boy, this is a big can of worms (pun intended) and one we’re just going to touch on because there are entire websites devoted to this very topic. In short, due to the increased demand for seafood, poorly regulated fishing practices which lead to overfishing, polluting fish farm operations and a warming climate that threatens natural lakes, rivers, and oceans, there are some fish and shellfish that are best avoided (or at the very least, limited to occasional consumption).
These overfished or endangered species include:
- Caviar (especially beluga sturgeon caviar) – The fish from which the eggs are harvested are slow to grow and reproduce making them susceptible to overfishing thanks to their high demand and market value.
- Chilean sea bass – Poor farming practices make them an undesirable choice and they’re also high in mercury.
- Eel – Eel of all types are overfished and may also high in polychlorinated biphenyls (PCBs) and flame retardants (endocrine disrupters) when harvested from rivers.
- Atlantic Salmon (farmed and wild caught) – In the wild, they’re overfished and fish farming operations present a significant environmental concern.
- Imported Basa/Swai/striped catfish (often called just “catfish”) – Often contaminated with Vibrio bacteria, a common cause of shellfish poisoning. Poor farming practices present significant environmental concerns and high antibiotic usage contributes to the formation of superbugs. Your best bet for catfish is those that come from U.S. farms, sometimes called ‘channel catfish’.
- Imported farmed shrimp – Usually from China or Vietnam, these are likely the worst offenders from an environmental and health perspective thanks to the way they’re farmed and the chemicals used to do so (including heavy doses of pesticides and antibiotics).
- Gulf shrimp present the issue of “wasted bycatch” meaning fish and sea turtles inadvertently harvested die in the process so our suggestion is to look for U.S. farmed or wild shrimp as a safer alternative.
- Imported king crab (from Russia) – Unsustainable farming practices make this an undesirable choice. King crab from Alaska, however, is a fine choice. But buyer beware, some statistics point out that a significant portion of king crab sold in the U.S. is imported from Russia and falsely labeled being from the U.S.
- Orange roughy – Since this fish is a bottom feeder and often a very old fish (it takes 20 years to reach sexual maturity before it can reproduce) it has higher mercury levels in addition to overfishing concerns.
- Atlantic bluefin tuna and Ahi tuna – These big fish are high in mercury and overfished nearly to the point of extinction and thus should be avoided. For sushi lovers, you’ll see blue tuna on the menu as ‘hon maguro’.
- Swordfish – Here’s one to avoid at all costs since it contains very high mercury levels, so much so that the Environmental Defense Fund cautions women and children to avoid it entirely and recommends men limit their intake of swordfish to no more than one serving (6 ounces) per month.
- King and Spanish Mackerel – Though rich in omega-3s, they’re also high in mercury so the FDA recommends women and children avoid it entirely. Atlantic mackerel, on the other hand, is much lower in mercury making it a safer way to get those healthy omega-3 fats.
- Grouper – This fish is both high in mercury and overfished, making it a less desirable choice.
How to choose more sustainable seafood.
OK, that was a lot to digest and more than you could possibly recall the next time you’re out for dinner or at the grocery store. Thankfully there are a bunch of free resources available to help you choose the most sustainable options which we’ve rounded up for you here:
Includes info for mercury, environmental concerns and recommended servings per month for each species. This is our favorite resource.
Available as a handy printable wallet card or searchable online database.
Learn more about sustainable fishing and what this label and certification means on the seafood you buy.
Use there product locator (set country filter to “United States” or other desired country) to get a list of certifed seafood brands and products.
How much mercury is too much?
Unfortunately, there is no set limit so you have to use your best judgment, which means choosing lower-mercury fish and shellfish whenever you can and limiting those that are high in mercury to less than one serving per month.
Now, all of this isn’t here to scare you into swearing off seafood forever, but rather, to help you make the best choices for you and your family. You can still enjoy the taste and health benefits of fish and shellfish when you know how to choose safer seafood – which hopefully we’ll have equipped you with the knowledge and resources to do so by the end of this post.
Our 8 Top Picks for Safer Seafood
- Wild-Caught Alaskan Salmon – Read the label to be sure you’re getting the real deal!
- Though wild-caught Alaskan salmon is considered the gold standard by some, there are threats to overfishing that come with high demand (and higher price tags too). According to Seafoodwatch.org, there are other great salmon options out there that aren’t all Alaskan wild-caught if you know what to look for. Our go-to’s for wild-caught Alaskan salmon when you want it delivered to your doorstep is Butcher Box.
- Chunk light or skipjack tuna – Look for those that are pole-and-line caught in the Eastern, Western and Central Pacific. Our go-to is light or skipjack tuna packed in water (we like this brand because it’s widely available and tested for the lowest possible levels of mercury).
- Because there are so many types of tuna, we encourage you to check out the Seafood Selector to determine which is the best choice for you, your family and your budget.
- Albacore tuna (white tuna) – Though higher in mercury, solid white tuna is high in omega-3 fats so the key is to choose low mercury brands and limit your intake to no more than 6 ounces per week. Look for pole- or troll-caught from the U.S. or British Columbia and those that are tested for mercury (we like this brand packed in water and this brand packed in olive oil).
- Pacific Sardines – Sardines are small fish and thus are low on the food chain making them a great low mercury choice. They’re also high in omega-3s and are super portable. If you’re new to sardines, we recommend choosing those that are boneless, skinless and packed in water as they’re the most ‘mild’ (like these, these or these). They’re not as scary as you think and taste remarkably similar to tuna. Of course, they’re also delicious when packed in olive oil, but slightly more ‘pungent.’ Consuming sardines with the skin on provides more healthy omega-3 fats.
- Pollock – This versatile, low-mercury white fish lends itself well to many dishes and is relatively budget-friendly. Look for those that are from the Atlantic (U.S., Norway, and Canada) as they are the most eco-friendly.
- Scallops – Scallops are a delicious, low-mercury seafood option and both wild and farmed versions are good choices. Look for those labeled as ‘dry’ that have not been treated with sodium tripolyphosphate, or STP.
- Crab – Though low in mercury there are some that are better than others from a sustainability perspective. Better choices include Red and Blue King Crab (from the U.S.), Stone crab (U.S.) and Snow crab. Dungeness crab is a fairly solid option too though it’s subject to overfishing so it pays to read the labels or ask your fishmonger where it’s from.
- Shrimp – We love shrimp, but treat it more like a delicacy than an everyday food because let’s be honest, ‘clean’ shrimp isn’t the easiest to source. Knowing what you’re looking for (wild vs. farmed and imported vs. domestic) is the key to selecting the safest shrimp.
You can compare the different types here or look for U.S. farmed or wild shrimp from the Northern U.S. when reading labels – these tend to be more widely available though they do have a ‘moderate’ environmental impact which is why we include shrimp in our diets less often than other types of seafood. Looks for packaging that has the Aquaculture Stewardship Council logo to find safely farmed fish.
- A note about preservatives: Shrimp often has preservatives added to it during processing. Look for words like Sodium Tripolyphosphate (STPP) or Trisodium Phosphate (TSP), sodium bisulfate, and ‘Everfresh’). Though considered ‘safe’ by the FDA they can have adverse health effects including sensitivity and excess sodium content and possibly even exposure to xenoestrogens in the case of Everfresh. It’s best to choose those without additives whenever possible.
Other good options
- Tilapia – Tilapia can be a good addition to your diet just be sure to choose wisely as farming conditions can vary from acceptable to downright deplorable (like those raised in China). Your best bet is to choose those that are farmed in the U.S. in recirculating aquaculture tanks where pollution can be closely managed. Learn more about better tilapia options here.
- Mussels – Unless you grew up on the coast you’re probably not familiar with mussels and all the delicious ways to enjoy them. Not only are they low in mercury and present a low environmental risk, but they’re also high in protein, rich in iron, a good source of vitamins A and B12, and a good source of omega-3 fats.
- Sablefish or Black Cod (wild caught from Alaska or Canadian Pacific) – Though moderate when it comes to mercury, this tasty and versatile white fish can be part of a healthy overall diet. The Environmental Defense Fund recommends that adults limit their intake to 4 servings per month and that children 12 and under consume no more than 2 servings per month.
How to choose the freshest seafood.
Whether you’re buying fresh or frozen, here are some tips to help you choose the freshest seafood.
Fish – Fresh, frozen, whole and filets
- Look for fish with firm flesh with a mild scent – Avoid those that have a strong ‘fishy’ smell. Saltwater fish should smell ‘briny’ or like the ocean and freshwater fish should smell like a clean pond.
- Fish should be moist but never slimy.
- Fresh fish should appear freshly cut. Avoid those that are sticky to the touch and/or sitting in a puddle of creamy, white fluid.
- Frozen fish should not have a strong fishy scent and the packaging should be taught and tightly sealed without evidence of blood or ice.
- If buying whole fish, look for those with plump, bulging eyes, skin and scales that are bright and metallic and gills that are clean and bright pink or red.
Mussels or Clams
When choosing mussels or clams, only select those that smell fresh (in this case, pleasantly briney) and whose shells are tightly closed. Avoid those with open, chipped, cracked or otherwise damaged shells as they are unsafe to consume.
If the shell is slightly open, give it a tap with your finger. If it closes quickly then it’s still alive and safe to eat. If it doesn’t close, discard it.
Avoid shrimp that smell like ammonia or have soft or slimy shells. They should have a mild ocean-like or briny scent and be firm without evidence of browning or blackening on the edges and free of black spots.
Scallops should be ivory, white or light pink without browning on the edges. Their texture should be firm (not mushy) and they should have a sweet smell. Sour smelling scallops are rotten and should not be consumed.
What does ‘previously frozen’ mean on fresh seafood?
Seafood is often ‘fresh frozen’ shortly after it is caught to ensure it retains its flavor, nutrition, and freshness. When you buy ‘fresh’ fish it may have been previously frozen. Take, for example, wild-caught salmon whose “season” only happens at a particular time of year. This fish is frozen for transport then thawed before hitting the shelves at your local market because “fresh” seafood is more convenient for consumers – you can smell the fish (which is hard to do when it’s plastic-wrapped and frozen) and take it home to cook right away without having to thaw it first.
While previously frozen seafood is still a solid choice and often the only choice for those not living on the coast, just know that once previously frozen fish or shellfish have been thawed it should not be re-frozen. You can cook the fish then freeze it in it’s cooked form but if you don’t plan to use it within a day or two your best bet is to forgo the fresh seafood and stock up on frozen fish or shellfish instead.
How to thaw frozen seafood.
There are two ways to safely thaw frozen seafood:
- Place it, in its wrapper or package, in a bowl in the fridge to thaw overnight, or
- Place the fish or shellfish in a large bowl in the sink and turn on the faucet just enough so that cool, running water continuously fills the bowl. Note, it’s important to keep the water running and for the water to be cool, not warm or hot for food safety reasons.
That concludes our How to Choose Safer Seafood post!
We know that it was a lot to read – and if you’re still reading, congrats – you’re now armed with all the info you need to make smarter decisions when it comes to seafood and your health (and that of the environment, too!).
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