How to choose sustainable seafood

The good news is that choosing better seafood doesn't require memorising long lists. A handful of habits — diversifying what you eat, checking a label, consulting a regional guide — makes a meaningful difference.

Why it matters

Oceans cover most of the planet and support enormous biodiversity. Poorly managed fishing and fish farming creates several distinct problems:

• Overfishing. When fish are caught faster than they can reproduce, populations collapse. Some commercial fish stocks have been significantly reduced from their historical levels.
• Bycatch. Many fishing methods catch species that weren't the target — seabirds, sea turtles, dolphins, sharks and juvenile fish of many species. Some methods have very high bycatch rates; others are highly selective.
• Habitat damage. Bottom trawling, for example, drags heavy gear across the seabed and can damage slow-growing habitats like deep-water coral.
• Aquaculture impacts. Some fish farming uses large amounts of wild fish for feed, generates waste concentrated in one area or requires antibiotics and chemicals. Other forms of aquaculture — particularly shellfish farming — can actually improve water quality and require no feed inputs at all.

None of this means avoiding seafood entirely. It means making more informed choices.

Simple rules for choosing well

Eat a wider variety

A small number of species — salmon, tuna, cod, shrimp — dominate seafood consumption in many countries. This concentrates pressure on those particular populations. Eating a wider variety of species, including less-familiar options, distributes the load more evenly and often means eating fish that are more abundant and less commercially exploited.

Check for eco-labels and certifications

Two major international labels are worth recognising:

• The Marine Stewardship Council (MSC) blue label is awarded to wild-caught fisheries that have been independently assessed as sustainable and well-managed. It's not perfect, but it provides third-party accountability.
• The Aquaculture Stewardship Council (ASC) label covers farmed seafood operations that meet standards for environmental and social responsibility.

Some national and regional certification schemes also exist and may be equally or more rigorous for local conditions.

Use a regional seafood guide

Which species are overfished varies significantly by ocean, region and season. A global guide can't tell you whether a particular species is sustainably managed where you live. Regional guides can.

Ask where it's from and how it was caught

A fish counter or fishmonger should be able to tell you the species, the country or sea area of origin, and the catch or farming method. If nobody knows, that's informative in itself. The same species caught by different methods in different places can have very different environmental footprints.

Wild-caught vs farmed

The wild-caught versus farmed debate is frequently oversimplified. Neither is categorically better or worse — method and context matter far more than the label.

• Well-managed wild fisheries with low bycatch and minimal habitat impact (such as hook-and-line or pot-caught) can be excellent choices.
• Poorly managed wild fisheries using destructive methods on overfished stocks are the opposite.
• Well-managed aquaculture — mussels, oysters, clams and some fish species farmed in low-density, low-chemical systems — can have a very small environmental footprint. Filter feeders like mussels and oysters need no feed inputs and can improve local water quality.
• Poorly managed aquaculture can involve large amounts of wild fish for feed, chemical use, escapes of non-native species and concentrated waste.

A farmed mussel is not in the same category as intensively farmed salmon fed on wild anchovies. A line-caught mackerel is not in the same category as trawl-caught shrimp with high bycatch. The specific situation matters.

Fishing and farming methods

Fishing method is one of the most important factors in environmental impact. In general terms:

• More selective methods (hook-and-line, handline, pot and creel fishing, spearfishing) tend to have low bycatch and minimal habitat impact. They're often used for premium, day-boat caught fish.
• Midwater trawls (targeting fish in open water, not the seabed) have less habitat impact than bottom trawls, though bycatch still varies.
• Bottom trawling drags gear across the seabed and can be significantly damaging to bottom habitats, though impact varies greatly by habitat type.
• Large purse seine nets used with fish aggregating devices (FADs) attract and trap many non-target species. The same nets used without FADs are considerably more selective.

Again, consult a regional guide for specific advice — sustainability assessments consider all these factors together for each species and fishery.

Reduce waste and eat proportionally

However sustainably seafood is caught or farmed, wasting it is a poor use of the resource. Treat seafood carefully:

• Buy fresh seafood with a plan to use it that day or the next, or freeze it promptly.
• Learn to use the whole fish when cooking fresh — stock from bones and trimmings, for example.
• Eat reasonable portion sizes rather than very large ones.
• Consider eating seafood slightly less often but choosing it more carefully when you do.

Plant-based seafood alternatives

Plant-based products designed to replicate the taste and texture of seafood have improved considerably and are increasingly available. They vary in quality and ingredient transparency — check labels as you would any processed food. For many people, the more practical shift is simply eating a wider variety of seafood and complementing it with plant-based protein sources like beans, lentils and tofu on other days, rather than switching to engineered alternatives.

Sustainable seafood checklist

• Download or bookmark your regional seafood guide and use it before shopping.
• Look for MSC or ASC certification on packaged seafood.
• Try at least one less-familiar fish species this month.
• Ask your fishmonger or fish counter where the fish is from and how it was caught.
• Include filter-farmed shellfish (mussels, oysters, clams) — often the lowest-impact seafood available.
• When buying tinned tuna, check the species and fishing method on the label.
• Store and use seafood promptly; freeze what you won't use the same day.