Sustainable Fish: All You Need to Know

Oct 11, 2023 | 9 minute read
Reading Time: 9 minutes

We all love to eat fish. It’s a great source of protein, it’s rich in omega 3, and most importantly, it’s delicious! However, finding sustainable fish can seem a little overwhelming. A dozen different labels decorate fish counters and supermarkets. Opinions vary on what is and isn’t sustainable. How can you know what to choose?

A selection of different fish in a fish market. Markets are one of the best places to find sustainable fish.
It looks delicious, but is it sustainable?

The truth is that eating sustainable fish is about more than just picking the right species. Where the fish comes from can be just as important as what it actually is. On top of that, the way it was caught makes a huge difference. Then there’s the question of farmed versus wild-caught fish.

Don’t panic. This article will guide you through the things you need to know and help you choose responsibly-sourced seafood. You can figure out what the different badges mean and which fishing techniques and farming methods to avoid. Prepare to dive into the murky waters of responsible seafood.

Wild-Caught vs. Farmed Fish

A lot of the confusion around environmentally-friendly fish seems focused on the question of “caught or farmed.” Some say that all fishing is unsustainable, while others insist that farming fish is inefficient and harmful to the planet. In fact, both ways of sourcing fish have their pros and cons. We need a mix of the two to keep fish on our plates long term.

Wild-Caught Fish Pros and Cons

A white commercial Shrimp trawler boat pulling in its nets, with seagulls flying around behind it.

There is an elephant in the room when it comes to wild-caught fish: overfishing. According to the United Nations Food and Agriculture Organization, one third of all the world’s fish stocks are being overfished, and over half are at maximum capacity. Important stocks like Atlantic Cod have collapsed completely, while many others are on the edge.

How did we get here? Part of the problem is that our favorite foods are often apex predators. This means that catching them has a knock-on effect on the entire food chain. On top of that, large-scale fishing comes with a lot of bycatch, which can’t be sold but is unlikely to survive, either.

It’s not all doom and gloom, though. Well-managed fisheries are, if anything, the most sustainable sources of seafood. There’s no need to feed the fish or to put chemicals into the water. The issue is that responsible fishing alone doesn’t produce enough food.

Aquaculture Pros and Cons

A group of round fish farms floating in the sea with boat and mountains in the distance

So the answer is aquaculture? Yes and no. Not all seafood is suited to farming. You can grow mussels with just the natural particles in seawater, but raising predatory fish like Tuna or Salmon takes a lot more energy. This leads to fish farms buying wild-caught fish to use as feed, which sort of defeats the point.

The biggest problem with farming fish isn’t making them grow, though. It’s what happens to the area in the process. If fish escape, they can become invasive and take over the local habitat. At the same time, chemicals and waste can contaminate surrounding waters if they’re not treated properly, as can the diseases and parasites common in intensive farming.

Despite all this, sustainable aquaculture is absolutely a thing. Growing less predatory fish and properly filtering wastewater allow farms to produce a huge amount of seafood with very little input. It can also be done year-round, and isn’t limited by where a species normally lives. It’s the perfect way to take the strain off our oceans, allowing them to slowly recover.

So which is better?

Aquaculture is ideal for shellfish, or species like Tilapia and Catfish that aren’t too picky about what they eat. However, well-maintained wild fisheries can be just as sustainable if not more so for large, predatory fish. It all depends on how you do it.

Sustainable Sources of Fish

A Steelhead Trout hanging from a fishing pole with sea and a yellow fishing boat in the background.

In order to really know if a fish is sustainable, you need to know how it was caught or raised. In general, techniques that recreational anglers use are the most sustainable, so catching your own fish is the best option if you can. There’s a lot less information about the type of farm a fish comes from, but if you’re buying from a fish market, you should be able to ask.

Sustainable Fishing Methods

Rod and Reel

Also known as hook and pole, this is about as close as commercial fishing gets to your typical angler on a fishing trip. Tuna and other large fish are often caught this way. There is little or no bycatch, because unwanted fish are quickly released. At the same time, rod-and-reel fishing gear has the smallest impact on marine habitats.

Jigs and Handlines

Similar to rod-and-reel fishing, but without the rod. Lines are pulled in by hand or by machinery once a fish is hooked, and generally only one or a few fish are hooked at a time. Handlines are used for all kinds of fish, from Snapper and Grouper to Tuna and Cobia, while jigs are mainly used for squid.

Traps and Pots

A stack of black commercial crab pots with orange floats.

Pots are mostly used for crabs and lobsters, but they’re also good for catching bottom fish like Cod and Rockfish. They’re designed to trap a certain size of a specific species. However, they often get lost and become “ghost gear,” which continues to catch fish for years or even decades.

Trolling Lines

Not to be confused with trawling nets, trolling is a way of catching fish by pulling hooks behind the boat to tempt predators like King Mackerel or Mahi Mahi. Once a fish bites, it is immediately reeled in and put back if it’s not what the fishing crew is after.


Harpoons are potentially the most sustainable way of catching fish. The fisherman or woman can see the fish they’re targeting before they spear it, so harpoons have the lowest amount of bycatch. They also can’t catch fish by themselves if they’re lost.

Sustainable Aquaculture

Land-Based Farms

A woman in a green jacket and grey hat holding a blue bowl while inspecting tanks in an indoor recirculating fish farm.

Land-based farms cause less damage to the surrounding environment than marine farms because the chemicals and waste don’t spread as easily. Ideally, seafood should come from indoor farms with recirculating tanks. This way, all the water is filtered and the fish themselves can’t escape and become invasive.

Bottom or Off-Bottom Culture

Growing seafood indoors is the most ecological option but shellfish like mussels and oysters can also be grown in the sea without any negative effects. They’re either grown on large trays on the bottom (bottom culture) or floating mesh nets (off-bottom culture). These are the best options if you can’t find indoor-farmed shellfish.

Unsustainable Fishing and Farming Techniques

Now to take a look at the other end of the scale. For wild-caught fish, it’s a question of “how much is being caught at once?” because large-scale techniques cause more bycatch and destruction. With aquaculture, it mainly depends on how well the farm is isolated from the surrounding area. Sadly, most seafood is produced with the following methods.

Fishing Techniques to Avoid


A large gillnet stretched along the bottom of the sea

These large walls of fishing net hang in the water and trap anything that tries to swim through. The problem with them is that turtles, sharks, and other marine life also get caught. As they’re left unattended, they regularly get lost and become “ghost gear.”

Bottom Trawls and Dredges

Bottom trawls are nets which drag along the seafloor to catch fish and crustaceans. Dredges are similar, but use large metal combs to claw up the bottom in search of shellfish and shrimp. They destroy the corals and plantlife on the ocean floor and stir up massive amounts of sediment.


Longlines are exactly what they sound like: miles and miles of fishing line, with hundreds or even thousands of secondary, hooked lines trailing off them. They’re used to catch Swordfish and Tuna, but also catch sharks, dolphins, and other marine life, especially if they’re left unattended.

Purse Seines

This is a style of commercial fishing where a net is pulled around an area, then the bottom is closed shut like purse strings, trapping entire schools of fish. The issue with purse seines is that anything else in the area also gets trapped, and is unlikely to survive.

Aquaculture Techniques to Avoid

Open Ponds

a large fish farm made up of open ponds next to the sea.

A lot of the world’s Shrimp comes from open, coastal ponds in Southeast Asia. Large areas of coastal habitat are destroyed to make these ponds, and near-coastal land is flooded with seawater, leaving it infertile once a pond is abandoned. Ponds aren’t all unsustainable, but they tend to have more of a negative impact than recirculating farms.

Fish Ranches

Fish ranching involves catching wild juvenile fish, most famously Bluefin Tuna, and growing them in pens. Wild fish are still being removed from the sea, and other fish need to be caught to feed them. On top of this, the ranched fish don’t get a chance to breed. This makes ranching the least sustainable option for farm-raised seafood.

Labels and Sustainable Seafood Guides

It’s easy to get confused by all the different terms. Ranching and farming, trolling and trawling, handlines and longlines – wouldn’t it be easier if there was just a label that said “sustainable”? Well, there is. In fact, there are quite a few.

There are various organizations which certify how sustainable fisheries and farms really are. The problem is that there are so many, it can be hard to tell which badges to trust. No organization is perfect, but these are some of the biggest and most respected ones out there.

Seafood Watch

The logo of Monterey Bay Aquarium's Seafood Watch.

Monterey Bay Aquarium’s Seafood Watch project is an amazing guide for finding responsible seafood, both in shops and in restaurants. It breaks down your best, second-best, and worst options for each species. The guide mainly focuses on the US and Canada, but you can also find info on fisheries and farms all around the world. Every fish lover should use it.

Marine Stewardship Council

The logo of the MSC, or Marine Stewardship Council.

The MSC is the most important accreditation body for wild-caught fish. It works to improve fisheries by working with them and monitoring them. The downside of this forward-looking approach is that their standards aren’t the highest. Even so, their logo means that a healthy amount of fish is being caught in a responsible way, obeying local laws and seasons.

Aquaculture Stewardship Council

The logo of the ASC, or Aquaculture Stewardship Council, an organization promoting sustainable fish.

The ASC is similar to the MSC, only focused on farmed fish and seafood. They assess the entire process, from the feed and land a farm uses to the health of the fish and the treatment of the workers. Again, they don’t have the strictest criteria because they see accrediting a company as a step towards helping them improve in the long term.

Friend of the Sea

The logo of Friends of the Sea, an organization which accredits farmed and wild-caught fish as sustainable.

Friend of the Sea has a much wider scope than most organizations. It covers both wild-caught and farmed seafood, as well as omega-3 tablets, shipping firms, cruises, and even whale watching tours. The group is generally considered to be trustworthy, but it has received criticism over the years for not carrying out completely independent reviews.

Global Aquaculture Alliance’s Best Aquaculture Practices

The logo of the BAP, or Best Aquaculture Practices, the accrediting arm of the Global Aquaculture Alliance.

The GAA is a consortium of large seafood companies. It created the BAP as a sustainability standard for the seafood industry. Their label works on a star system. It ranges from one star, which just certifies the processing plant, to four stars, meaning the entire supply reaches their standards. It’s best to stick to products with three or four stars.

How to Eat Sustainable Fish

The only way to really know that your food is sustainable is to go out and catch it yourself, but there are certainly ways to minimize the impact on the planet. We’ve covered a lot of those ways in this article: You’ve learned how fish are caught and raised and got to grips with the different groups involved. To round off, here’s a summary of our tips on eating responsibly-sourced fish.

A haddock being held up by a fishmonger in blue overalls. There are several other types of fish lying on ice on the fish counter.

Find out how and where it was caught: This should be displayed on the box. If you’re buying fish from a market, ask the person selling it. Try not to buy fish without this information.

Check the guide: Download the Seafood Watch app and check the credentials of any fish you’re about to buy. This is the easiest and most effective way to get a straight answer.

Look at the logos: If you can’t find information on the specific farm or fishery a product came from, look for the badges listed above – they’re not perfect, but they’re a good indicator.

Enjoy! Finding sustainable fish isn’t always easy and it can be expensive. However, it’s well worth it when you get to enjoy delicious food and know that you’ve done your best to be responsible about it.

What’s your favorite sustainable fish to eat? Are there any organizations or techniques that we forgot to mention? Let us know in the comments below, we would love to hear from you!

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