Sustainable fish comes from sources, whether wild-caught or farmed, that can continue producing seafood indefinitely without depleting fish populations or damaging marine ecosystems. In practical terms, it means the fish on your plate was harvested at a rate that lets the species reproduce and maintain healthy numbers, using methods that minimize harm to other ocean life and habitats. It sounds simple, but a lot of science, management, and monitoring goes into making that happen.
As of 2021, only 62.3 percent of the world’s marine fish stocks were fished within biologically sustainable levels, a number that has been steadily declining. That means nearly four in ten monitored fish populations are being harvested faster than they can recover. Understanding what “sustainable” actually requires helps you make better choices at the grocery store and fish counter.
The Three Pillars of Sustainability
The United Nations Food and Agriculture Organization defines sustainable fishing around three connected ideas: it must be environmentally non-degrading, economically viable, and socially acceptable. A fishery that protects ecosystems but destroys local livelihoods isn’t truly sustainable, and neither is one that’s profitable but collapses fish stocks for future generations.
In practice, this means sustainable fisheries conserve the natural resource base, including water, habitats, and genetic diversity of fish populations, while still meeting human needs today. The goal is that your grandchildren can eat the same species you’re eating now, caught or farmed in the same waters, because the system was designed to last.
What Makes Wild-Caught Fish Sustainable
For wild-caught fish, sustainability comes down to four main factors: stock health, bycatch, habitat impact, and effective management.
- Stock health. The target species needs to be abundant enough that current fishing levels aren’t shrinking the population. Scientists assess whether a stock is overfished (too few fish left) and whether overfishing is currently occurring (catching them too fast).
- Bycatch. Fishing nets and lines inevitably catch species that weren’t the target. Sustainable fisheries minimize this and have no more than a negligible impact on threatened, endangered, or protected species. The Marine Stewardship Council now requires that all marine mammals, seabirds, amphibians, and reptiles are treated as protected species during assessments.
- Habitat impact. Dragging heavy gear across the ocean floor can destroy habitats that take decades to recover. Sustainable fisheries avoid serious or irreversible harm to sensitive marine environments, and the sensitivity of a habitat is assessed based on how long it would take to bounce back from fishing activity.
- Management. Good intentions mean nothing without enforcement. Sustainable fisheries need harvest strategies that control fishing pressure, monitoring systems, and the ability to respond when conditions change.
Beyond the target species, truly sustainable fishing also considers the broader food web. Removing too many small forage fish, for example, can starve the larger predators that depend on them, triggering chain reactions throughout the ecosystem.
How Fishing Methods Matter
The gear used to catch fish has a huge effect on sustainability. Research comparing trawls, longlines, and pots (traps) in the same fishery found clear differences. Trawls, which drag large nets through the water or along the seafloor, had the highest bycatch rates and the most habitat damage. Pots had the lowest bycatch because they’re selective: fish swim in, and non-target species can often escape or be released alive. Longlines caused the least habitat damage because they don’t contact the seafloor the way trawls do.
Hook-and-line methods and pole-caught fishing tend to be among the most selective, letting fishers target specific species and sizes. Bottom trawling, on the other hand, is one of the most destructive methods for seafloor ecosystems, though it remains widely used because it’s efficient for catching large volumes. Ghost gear, meaning fishing equipment that’s been lost or abandoned in the ocean, is another concern. Lost nets and traps keep catching and killing marine life for years. Certification programs now require fisheries to have measures in place to minimize gear loss and account for any lost equipment.
What Makes Farmed Fish Sustainable
About half the seafood eaten globally is farmed, so aquaculture sustainability matters just as much as wild-catch practices. Farmed fish raises a different set of concerns: what the fish are fed, how waste is managed, whether farm operations pollute surrounding waters, and increasingly, how the animals are treated and how workers on the farms are protected.
The Aquaculture Stewardship Council sets standards covering animal welfare, human rights, and environmental stewardship. One major issue is feed. Many farmed fish like salmon are carnivorous and traditionally fed diets containing wild-caught fish, which can shift the overfishing problem rather than solve it. Sustainable aquaculture standards now require responsible sourcing of all major feed ingredients, pushing farms toward plant-based or alternative protein feeds where possible.
Other concerns include the use of antibiotics (which can breed resistant bacteria in surrounding waters), escape of farmed fish into wild populations where they can dilute genetic diversity, and the destruction of coastal habitats like mangroves to build farm pens. A sustainably certified farm has to demonstrate it’s managing all of these risks.
Certification Labels to Look For
Several third-party organizations evaluate and certify seafood sustainability, giving you a shortcut at the store.
The MSC blue fish label covers wild-caught seafood. Their standard evaluates stock health, ecosystem impact, and management effectiveness. Version 3 of their standard added stronger protections: fisheries that retain sharks must now have a fins-naturally-attached policy with no exceptions, and every assessment must explicitly consider the impact of lost fishing gear. For data-limited fisheries where less scientific information is available, a precautionary approach is required.
The ASC green label covers farmed seafood. Their farm standard addresses environmental stewardship, animal welfare, and labor practices, while a separate feed standard covers responsible ingredient sourcing. Both organizations use chain-of-custody tracking to verify that what’s sold as certified actually came from a certified source.
Monterey Bay Aquarium’s Seafood Watch program takes a different approach. Rather than certifying individual fisheries, it rates seafood species and sources as “Best Choice,” “Good Alternative,” or “Avoid” based on four criteria: impacts on the target stock, impacts on other species (including bycatch and bait use), management effectiveness, and impacts on habitats and ecosystems. Each criterion gets a color-coded score, and the combined scores produce the final recommendation. You can check ratings for free through their app or website before you buy.
Which Fish Are Considered Sustainable
Sustainability isn’t really a property of a species in isolation. The same type of fish can be sustainable from one fishery and overfished from another, depending on local stock health, management, and how it’s caught. Alaska pollock caught in well-managed U.S. federal waters, for example, is generally considered a strong choice, while the same species from a poorly regulated fishery elsewhere might not be.
That said, U.S. federally managed fisheries are built around science-based management processes, which is why NOAA considers seafood from these sources inherently sustainable. Species commonly available from these fisheries include Alaska pollock (used in fish sticks and imitation crab), American lobster, and various crab species. Small, fast-reproducing fish like sardines, anchovies, and herring also tend to be more resilient to fishing pressure than large, slow-maturing species like orange roughy or Chilean sea bass.
When choosing fish, the combination of species, origin, and catch method tells the full story. A label that says “wild-caught salmon” doesn’t tell you much. “Wild-caught Alaskan sockeye salmon, troll-caught” tells you the stock, the region, and a low-bycatch fishing method, which is enough information to actually evaluate sustainability.
How to Use This at the Store
Look for the MSC or ASC labels on packaging as a reliable starting point. If there’s no certification label, check Seafood Watch ratings on your phone. Pay attention to where the fish is from and how it was caught, both of which are sometimes listed on packaging or available from the fishmonger.
Choosing species lower on the food chain, like mussels, clams, sardines, and farmed oysters, is one of the simplest sustainability moves you can make. These species require little to no feed, filter water as they grow, and are harvested with minimal bycatch or habitat disruption. Diversifying the species you eat also helps. Consumer demand concentrated on a handful of popular fish like salmon, shrimp, and tuna puts disproportionate pressure on those stocks, while dozens of equally delicious species go underappreciated.