The word sustainable can be printed on a seafood label by anyone. MSC and ASC certifications cannot. Those have to be earned and verified by independent auditors against published standards, which is why the little blue-and-teal stamps in the corner of a tin are worth paying attention to.

What "Sustainable Seafood" Actually Means (and Why the Word Gets Misused)

Walk through any grocery store seafood aisle, and you'll find the word "sustainable" on a lot of packaging. It's a compelling word, and it's also completely unregulated. Any brand can print it on its label, regardless of the process used. 

However, for wild-caught fish, sustainability has a real definition: the population is managed so it can replenish itself year over year. For farmed fish, it's about husbandry and environmental conditions rather than catch quotas. Neither definition is regulated on a label unless someone has actually verified it. That's where MSC and ASC certifications come in.

MSC: The Certification for Wild-Caught Fish

“Wild-caught” is often used as a sustainability shorthand, particularly in the tinned fish space. It isn't. A wild-caught product from an uncertified fishery tells you nothing about whether the population is being managed responsibly. The MSC stamp ensures proper management and accountability.

The Marine Stewardship Council (MSC) is the international standard for wild-caught seafood sustainability. Founded in 1997 as a nonprofit, its certification is widely recognized by major grocery retailers as their sourcing benchmark for wild-caught seafood, a meaningful signal of the standard's credibility beyond the brand level.

To earn MSC certification, a fishery has to meet criteria across three areas:

• Health of the fish stock

• Environmental impact of the fishing operation

• Effectiveness of the management system overseeing it

That means catch quotas are appropriate to support population replenishment, using fishing gear and methods that limit bycatch (the unintended catch of non-target species), and traceability that follows fish from the sea to the shelf.

MSC also requires fair labor practices as part of its chain-of-custody standards. Sustainability doesn't mean much if the people catching the fish are being exploited in the process.

ASC: The Certification for Farmed Fish

The Aquaculture Stewardship Council (ASC) operates under the same umbrella as the MSC, but covers farmed seafood. While the MSC asks, "Is this fishery leaving enough fish in the water?", the ASC asks, "Is this farm operating responsibly for the fish, the people, and the surrounding environment?"

ASC criteria address the following:

• Crowding: how densely fish are kept

• Feed quality: what they're being fed and whether it's appropriate for the species

• Water quality: the condition of water within the farm and its impact on surrounding waterways)

• Broader environmental footprint

Human rights and supply-chain labor standards are also part of the assessment, a critical component that distinguishes genuine certification from a marketing claim.

A Quick Note on Farmed Seafood

There's a persistent cultural bias against farmed fish in the U.S., and it's worth unpacking. "Wild" sounds right and natural; "farmed" sounds industrial and suspect. However, a well-run, ASC-certified farm produces fish under monitored, regulated conditions, which in some respects gives you more consistency and traceability than a wild fishery can. The certification is what separates responsible aquaculture from the kind that actually deserves skepticism.

What Goes Into Earning These Certifications 

Both MSC and ASC certifications are issued by independent third-party auditors who assess fisheries and farms against relevant standards. That independence is the meaningful part. It's what separates a certified product from one where a brand simply decided its practices were good enough to call sustainable.

For a wild fishery pursuing MSC certification, the audit looks at scientific data on fish stock health, the fishing methods and their impact on the broader ecosystem, and the management structures that govern the fishery. The process is rigorous and not quick. Fisheries can take years to move through the assessment, and certification isn't permanent. It's valid for five years, with annual check-ins along the way and a full reassessment required to renew. A fishery that slips below the standard can have its certification suspended or pulled. 

For a farm pursuing ASC certification, auditors assess on-site conditions, including water quality monitoring, stocking density, feed sourcing, waste management, and labor practices throughout the supply chain. Farms are re-audited annually to maintain status.

When you see the blue MSC label or the teal ASC label on a product, a third party has verified that the claims hold up. That's the meaningful signal, and it's why major retailers use these certifications as sourcing benchmarks. They represent a level of verification that a brand can't manufacture on its own.

Why This Matters for What's in Your Tin

Across Fishwife's tinned fish lineup, every product is either MSC- or ASC-certified. That's a baseline sourcing requirement, not an afterthought.

For the wild-caught products, MSC certification means the fisheries we source from have been independently verified to manage their catch responsibly. The populations are monitored. The gear is selected to limit bycatch. The fish can be traced back to a certified point of origin. That holds for our sardines, Cantabrian anchovies, albacore tuna, and smoked mackerel, each sourced from MSC-certified fisheries.

For the farmed products, ASC certification means the farms operate under verified standards for animal welfare, water quality, and labor practices. That applies to our smoked salmon and rainbow trout, both sourced from farms that have passed independent ASC audits. Farmed doesn't mean a shortcut was taken. With ASC-certified products, the opposite is true.

A "wild-caught" label on a competing product with no certification behind it is a branding decision, not a sustainability claim or a representation of how the fish is sourced. The label alone doesn't tell you anything meaningful about how the fishery is managed or whether the population can sustain the harvest level. These certifications exist precisely because "sustainable" needed something real to back it up.

How to Read a Label: What to Look For and What to Ignore

Not every claim on a seafood label means the same thing. Some are verified. Some are marketing. Here's how to tell the difference.

The MSC Label: Wild-Caught and Verified

The MSC label is a blue oval with a white fish and a checkmark. It appears on products sourced from certified wild fisheries and means an independent third-party auditor has verified the fishery against the Marine Stewardship Council's standards for stock health, bycatch limits, and traceability. If it's on the tin, someone checked.

The ASC Label: Farmed and Verified

The ASC label is teal, with a stylized fish. It appears on products from certified aquaculture operations and carries the same third-party verification requirement as MSC. Animal welfare, water quality, feed sourcing, and labor practices have all been assessed on-site by an independent auditor.

"Wild Caught": A Processing Descriptor, Not a Sustainability Claim

Wild-caught tells you the fish wasn't farmed. It says nothing about the health of the fishery, the size of the catch relative to the population, or whether the fishing method damages non-target species or habitats. From an uncertified fishery, it's an origin descriptor with no sustainability backing.

"Sustainable," "Responsibly Sourced," and Similar Claims: Unverified Unless Stamped

These terms are unregulated. Any brand can use them. Without an MSC, ASC, or other recognized third-party certification behind the claim, there's no independent verification that the label means anything. It may be true. It's also impossible to confirm.

"Natural," "Pure," "Clean": Marketing Language

None of these terms has a regulatory definition in the seafood industry. They're brand decisions, not standards. Treat them accordingly.

What is Sustainable Seafood: The Bottom Line

"Sustainable" is one of the most overused words in the food industry, and seafood is no exception. It gets printed on packaging, worked into brand copy, and repeated in marketing until it stops meaning anything at all. MSC and ASC certifications exist because the world needs something to back them up: an independent standard, a third-party audit, and a renewal process that ensures the claim holds up over time.

When you see those stamps, you're not looking at a brand telling you what it wants you to believe. You're looking at verification. That's a meaningful distinction, and it's worth keeping in mind when you're deciding what to put in your cart.