Can Fish Ever Be Sustainable? A Practical Guide to Eating Better for our Oceans

When it comes to eating fish, the waters can feel murky. Should we be eating fish at all? Is wild-caught always better than farmed? And what about those "sustainable" labels — do they actually mean anything? It’s a lot to untangle, and honestly, it can be tempting to throw in the towel and avoid fish altogether.

In my opinion, it’s not all or nothing. With a little know-how, you can enjoy seafood in a way that’s gentler on the planet. By making small, thoughtful choices like choosing different species, eating with the seasons, and wasting less, we can make a huge difference in how we support our waters.

Let’s dive in.

Eat Different

One of the simplest ways to eat fish more sustainably is to eat lesser known varieties more often. The UK’s love affair with cod, haddock, salmon, and tuna has led to intense overfishing, with stocks of some species struggling to recover. Rather than making fish a these fish a weekly staple, treat them as an occasional indulgence — and when you eat your weekly fish, make the choice count.

For example, swapping cod for more abundant species like hake or pollock can ease pressure on overfished populations. Or, if you’re craving seafood, try mussels or clams, which are farmed with much less environmental impact in the UK and actually help clean the water as they grow. They are also abundant in our waters and often forgotten about.

Eating fish less often (but choosing lesser known fish and seafood options when you do) is one of the most impactful ways to support ocean health.

Know Your Labels

As with all animals it makes sense to choose the highest quality you can afford when you buy it to ensure the people that catch/rear them are paid fairly, and that it’s the best quality you can put on your plate. But with labels like MSC-certified, ASC-certified, and organic, it can feel like a minefield. The best approach? Buy from sources that are transparent about how their fish is caught or farmed.

For wild-caught fish, look for low-impact methods like hand lining or pole-and-line fishing, which target specific species and minimise bycatch (extra fish and sea creatures that get caught in nets by mistake). Small day boats that fish closer to shore are often a better bet than large trawlers, which can devastate the seabed and release huge amounts of carbon stored in the ocean floor (yes – it's there too!).

When it comes to farmed fish, go for species that don’t require wild fish as feed, like mussels or clams. If you want to eat salmon, why not swap for good quality trout – a fish that tastes very similar to salmon and isn’t as over-farmed. Salmon is a contentious topic in the UK, and many chefs now are dedicated to taking it off their menus because of the environmental impact. Take a look at Off The Table for more information on why salmon shouldn’t be on your shopping list.

It’s a classic case of quality over quantity and your plate (and the planet) will be better for it.

Know what’s in Season

Just like fruit and vegetables, fish have seasons. Eating seafood when it's naturally abundant reduces the need for harmful fishing practices and helps populations replenish. But because supermarkets sell fish year-round, it’s easy to lose touch with what’s actually in season. 

For example, native sea bass spawns in spring, so eating it in early summer gives stocks time to recover. Mackerel is plentiful in warmer months, while herring is at its best in autumn. Even shellfish have seasons — oysters are best in colder months (think of the old rule: eat oysters in months with an "R"). 

If you’re unsure what’s in season, resources like the Marine Conservation Society’s Good Fish Guide can help. Or, better yet, chat with your local fishmonger — they’ll know exactly what’s at its peak and can help you try something new. 

Eating seasonally not only supports healthier fish populations but also means you’re getting seafood at its freshest and most flavourful. Win-win. 

Eat the Whole Fish

Reducing waste is a huge part of sustainability, and that applies to fish, too. Buying a whole fish is often cheaper per kilo and gives you more to work with — plus, it helps you respect the animal by using as much as possible. 

Roast a whole mackerel or sea bream, then flake the leftovers into fishcakes, salads or grain dishes. Use the bones to make a rich, nutrient-dense stock. Even fish heads can be turned into a flavour-packed (and very nutritious) broth. 

It’s an easy way to stretch your fish further, reduce food waste, and connect more deeply with what’s on your plate. 

Eating fish sustainably isn’t about strict rules or getting it right every time. It’s about awareness. By cutting back, choosing fish that are caught with care, and paying attention to what’s in season, we can still enjoy the flavours of the sea without depleting its resources.  So next time you fancy fish, pause, consider your options, and know that even a little bit of thought can make a real difference.