Sustainable Seafood - How to purchase with confidence

The world's appetite for seafood is placing pressure on the commercial fishing industry.
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A sea of choices. Many of us flock to the coasts during the summer to enjoy swimming, boating, fishing, a break from the heat and delicious seafood. In today’s globalized world, even those of us who live far from the coast have access to a plethora of seafood choices in our local restaurants and grocery stores. As you peruse your seafood options, you may find yourself wondering which seafoods are best to eat, and I am not just talking taste.

Which seafoods are sustainable?

This simple question can feel overwhelming, but if you know the right questions to ask, you can find out which fish and shellfish were harvested sustainably and which were not.

But what does it really mean for seafood to be sustainable?

By the simplest definition, a seafood product can be considered sustainable if it is harvested in quantities small enough to prevent negative impacts to its population and is caught in a way that does not harm other species or marine habitats. Sustainability is all about the future productivity of marine ecosystems. But without a crystal ball, how can we know how the actions we take today will influence tomorrow’s ocean?

Since fisheries scientists and managers are not fortune tellers, they rely on several different metrics to determine if fish are harvested in a manner that promotes healthy marine ecosystems in the future. Our seafood choices consist of many different species caught with many different methods from all corners of the globe, so there is no single metric that can be used to determine if a given type of seafood is or is not sustainable. There are, however, a few key concepts that are commonly used to assess seafood sustainability. By understanding a few of these concepts, you too can be an educated seafood consumer.

A map of local and sustainable seafood options by region. - Hilary Kotoun
Hilary Kotoun

The questions you should ask:

Use these five questions to find out if your seafood is sustainable:

What type of gear was used to catch this fish or shellfish?
How much bycatch does this gear usually cause?
Does this gear type damage marine habitats?
Where on food chain does this species fall?
Is it wild or farm-raised?

Fishing Gear

Gear type is one of the most important aspects of seafood sustainability because it has a major impact on other species and on marine habitats. And trust me, there are a lot of different gear types out there. There are two very basic generalizations that you should understand about the relationship between gear type and seafood sustainability.

1. Indiscriminant gear, such as purse seines, gill nets and trawls, usually results in more bycatch (more on that below) compared to selective gear, such as hooks, traps, and harpoons. Yes, you can buy seafood caught by harpoon!

2. Gear that touches the seafloor (such as bottom trawls and dredges) is more likely to damage marine habitats than those that avoid the seafloor.

Ask your server or seafood dealer how the fish was caught. You can also find out how your favorite seafood is normally caught with a quick Google search.

Discarded fish

'Bycatch' refers to fish that are caught incidentally by fishermen who are usually targeting one or two species of fish. In the United States, fishermen are permitted to fish on a species-by-species basis and are subject to regulations on when and where they can fish and on the size and number of the fish they are allowed to keep.

'Bycatch' can include a species that a fisherman is not permitted to harvest, such as a fish caught out of season, or one that is smaller or larger than the legal size. Sometimes fishermen accidentally catch too many fish of a particular species and they have to throw some back. This is also considered bycatch.

Fishery regulations in the United States require that most bycatch be discarded at sea. Because fish and shellfish discarded as bycatch are usually dead, bycatch can have a major negative impact on marine ecosystems.

Habitat damage

If fishing gear touches the seafloor it can damage marine habitats. This causes major impacts on other species and on the overall health of marine ecosystems. Bottom trawls are the most notorious example of fishing-induced habitat destruction. Bottom trawls catch fish by dragging heavy gear along the bottom. They are particularly harmful to rocky habitats, sponges, and corals. Pole-caught, handline, troll, or trap-caught seafoods are better options because they cause very little habitat destruction.

Food chain

Fish that are low on the food chain are generally sustainable options because they are, for the most part, more abundant than fish that are higher on the food chain. They also reproduce at a younger age, which helps them recover relatively quickly from low to moderate levels of overfishing. In the U.S. we tend to prefer long-lived, predatory fish such as cod, tuna, swordfish, salmon, and halibut. By expanding your tastes to include species lower on the food chain, you can support healthy marine ecosystems by reducing pressure on the larger species, several of which are overfished. Some tasty options that are low on the food chain include mackerel, tilapia, catfish, mussels, clams, and oysters. There are some exceptions to this rule, which is why it is important to do a bit of research when considering your seafood options. For example, shrimp are low on the food chain, but most of the shrimp available in the U.S. was farm-raised in ways that cause significant habitat damage. Americans consume more than one billion pounds of shrimp every year, and 90% of that is imported from overseas aquaculture facilities. Shrimp aquaculture operations in some developing countries have a particularly bad track record for habitat destruction and human rights violations.

Wild vs. farm-raised

Most of the seafood consumed in the U.S. is harvested from wild populations. However the amount of farm-raised fish and shellfish in U.S. seafood markets is rapidly expanding. There are many benefits associated with aquaculture, but also many environmental costs. Aquaculture tends to generate strong opinions. You should do your own research before forming your opinions on aquaculture. Some argue that aquaculture is necessary to feed a growing human population while also supporting the health of marine ecosystems by taking pressure off wild stocks. Others argue that aquaculture relies too heavily on wild-caught fish to create feed for farm-raised fish, that it pollutes the environment with fish waste and antibiotics, and that escapees can harm wild populations by introducing diseases or altering the wild gene pool.

Farm-raised mussels, clams, and oysters are generally beneficial to marine ecosystems because they feed by filtering seawater and do not require artificial feeds. They also improve water quality in the surrounding region. If you purchase these farm-raised species you can feel confident that you are supporting healthy marine ecosystems. For other farm-raised species, speak with your seafood dealer and decide if they are sustainable options or not. In general, it is best to avoid seafood from aquaculture operations in developing countries because these countries tend to have fewer regulations on aquaculture compared to the United States.

Eat local

A great way to learn more about seafood sustainability is to buy your seafood locally and talk with fishermen and dealers specializing in seafood. You may be able to find seafood at your local farmers’ market or join a Community Supported Fishery (CSF). If you buy your seafood from a farmers’ market or a CSF, you can feel confident that it is sustainable. CSFs follow the model of Community Supported Agriculture in that they bring fresh, seasonally available, locally caught seafood directly to consumers. They also offer a great way to support both healthy marine ecosystems and coastal economies.