How to Know if Fish is Sustainable

By Alba Charles . Updated: January 20, 2017
How to Know if Fish is Sustainable

We sometimes think that the ocean is vast and has endless resources, but we couldn't be more wrong. Not too long ago fish species were numerous and populations were healthy. However, nowadays the numbers of some specific species are critically low and some species, such as the bluefin tuna, are at risk of extinction. If the demand of fish continues as high as it is now, more species could become endangered and even disappear. The harmful fishing methods, the poor fishing management and the increase of human population are putting a great pressure on marine ecosystems, endangering them. For this reason, it is very important to make the right choices when it comes to choosing the fish we want to eat. By choosing sustainable seafood we ensure that populations are maintained and that the marine ecosystems are taken care of. But, how do you know if fish is sustainable? The quality standards for sustainable fish are not very clear and sometimes it can be difficult to know the origin of the seafood we're buying. In this case, asking the right questions will be the key.

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When is seafood considered sustainable?

Seafood is considered sustainable when it comes from fishery practices that maintain ecosystems and species populations without reducing the ability of these species to grow. Sustainable fish is catched with methods that don't suppose negative impacts to the population or other species.

Identifying which fish is sustainable is an arduous task. The seafood we consume comes from many different parts of the planet and it's caught with many different methods, so it is very difficult to trace the source of it. Also, there is no simple labelling system that shows that fish is 100% sustainable, as it happens with wood products and the Forest Stewardship Council (FSC) logo.

Why is fish sustainability important?

According to the Seafood Watch, more than half of the fisheries in the world are overfished. This has devastating effects on fish populations, habitats and in the overall health of marine ecosystems around the world. Overfishing destroys habitats and reduces populations to numbers that could even be impossible to recover. If we want to conserve the seas and oceans it is important to start eating fish in a smart way.

Questions about sustainability

Therefore, with no easy quality system to determine whether fish is sustainable, we need to do some research and ask the right questions when buying fish. These are the most important concepts that need to be taken in mind when buying seafood:

  • Which method was used to catch it.
  • Where on the food chain is this species.
  • Whether it's wild or farm-raised.
  • Where it comes from.

Sustainable fishing methods

The fishing method is one of the most important aspect of seafood sustainability. Using the correct fishing methods will ensure that it makes the less impact possible on other species and marine habitats. The current fishing methods can be separated into sustainable and not sustainable.

Sustainable fishing methods

These are the fishing methods that maintain the populations of seafood as well as the marine ecosystem of the area. These methods guarantee that there will be populations of seafood wildlife available for the future. The most common are:

  • Pole and line. This method catches the fish one by one. It is highly selective and doesn't have impact on other marine species and habitats.
  • Jig. This is a hand-catching method which consists of a grapnel attached to a line jerked in the water to catch the fish. It is a very selective and targeted method which makes it environmentally responsible.

Unsustainable fishing methods

  • Purse seining. This method uses a net to herd fish together and then catch them by pulling the net. It is a highly unselective and catches many other species of fish. This method is used when fishing schooling fish or the species that come together to spawn. However, many other species get trapped in the net.
  • Longlining. This method uses a very long of up to 100 kilometres that is dragged behind a boat. This line has thousands of hooks attached to smaller line. This method is efficient because it causes many fish at a time, but, like purse seining, it can catch many other unwanted fish species.
  • Trawling. This is one of the most used methods nowadays. This method works by towing a funnel-shaped net through the water. If it's used near the ocean floor it can be very damaging, as it destructs the habitat, mostly corals and sponges. It also has a lot of bycatch, i.e. catching other species.
How to Know if Fish is Sustainable - Sustainable fishing methods

Species lower on the food chain - a more sustainable option

Generally the species that are lower on the food chain are more abundant than the ones that are at the top. These species also reproduce faster and at a younger age, helping the recovery of populations. Some of these seafood species lower on the food chain are:

  • Mackerel
  • Tilapia
  • Catfish
  • Mussels
  • Clams
  • Oysters

There are some exceptions, however. Shrimps are very low in the food chain, but some countries such as the US they are farm-raised. The majority of these shrimp farms are placed in developing countries that have a bad record for habitat destruction and human rights violations.

According to Greenpeace, these are some of the species of seafood that should be avoided:

  • Atlantic cod (except line-caught Icelandic)
  • Plaice
  • Tuna (except skipjack)
  • Tropical prawns
  • Haddock (except line-caught Atlantic)
  • Swordfish
  • Atlantic salmon
  • Monkfish
  • Atlantic halibut
  • Sharks
  • Skates
  • Rays

The list is longer than these, but the environmental group claims that these are the seafood species that are caught using the most destructive fishing methods.

How to Know if Fish is Sustainable - Species lower on the food chain - a more sustainable option

Is farm-raised fish sustainable?

Some people believe that farm-raised fish is a more sustainable alternative, as it doesn't have an impact on the wild populations. However, some farms use chemicals and other products on their fish and water which could cause a problem not only for the environment but also for human health.

There is no international standard for fish farms, however, some countries have better standards than others. If choosing seafood from a farm it is better to avoid some Asian countries where standards for both environmental health and human rights are not too high.

Also, some breeding stocks used in farmed fisheries are taken from wild populations.

In terms of sustainability, it is always better to choose wild fish caught using selective methods than farm-raised.

Buying locally to ensure sustainability

Another great method of ensuring the sustainability of the seafood you're buying is to buy local. Going to the market and getting fish from the local fishmonger is the best option. Not only you will make sure that this fish hasn't gone through a lot of transportation, you'll also be able to speak with the fishmonger and ask him/her about the fishing methods used to catch the seafood. If they are happy to answer your questions you can be sure that the fish you're buying is sustainable. If they don't want to answer or act as if they're hiding something, it is better to leave that fish where it is.

How can you tell if the fish in the supermarket is sustainable

As previously said, there is no standard labelling system that ensures that the fish you're buying is sustainable. Unlike what it happens with wood products and the FSC standard, there is no easy way to know if the food we're buying is sustainable or not. But there are some things we can do to try to know more about the source of the fish:

  • If you're buying canned fish, take a close look at the labels. Labelling on food products has improved lately, although there is still room for much improvement. If you're buying canned fish read carefully the labels and you'll find information about the seafood you're purchasing. However, some brands still don't add many information on the cans, which makes it difficult for consumers. As a general rule, if a can doesn't contain many information about the fish inside it means that it's not sustainable. If you want to know more, you can check this article and learn what the information on canned tuna labels mean.
  • Look for logos. Some cans have the logo of the Marine Stewardship Council (MSC), a certification scheme awarded to wild fisheries. This logo ensures that the fisheries meet various sustainability criteria, making this fish safe to buy. However, the environmental group Greenpeace doesn't endorse this certification scheme because some of the fisheries awarded this logo are still unsustainable.
  • Ask the fish seller. If the fish seller is transparent about the origin of the fish, you can be sure that the seafood you're buying is sustainable.
How to Know if Fish is Sustainable - How can you tell if the fish in the supermarket is sustainable

Should we stop eating fish?

Surely fish is a great source of nutrients, but we need to consume it responsibly. It is now believed that we're consuming too much fish, which has a detrimental impact on marine life and ecosystems. Eating less fish is the best thing to do in order to maintain the populations and ensure the health of the oceans and seas.

If you want to read similar articles to How to Know if Fish is Sustainable, we recommend you visit our Food & drink category.

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