Wild vs. farmed seafood: Who wins?

Fish for sale at the market. Photo via  flickr  used under creative commons.

Fish for sale at the market. Photo via flickr used under creative commons.

After a busy day you are wandering through the aisles of your local supermarket, trying to decide what to have for dinner. You pass by the seafood section and think it’s a good idea. There are so many choices though: shrimp, halibut, crab, salmon, and trout. The salmon catches your eye, though, and you reach down to grab one but stop when you see two different labels.

One label says “WILD” while the other says “FARMED.” Oh no, yet another decision! The farmed salmon is five dollars cheaper than the wild salmon, but you have heard that wild seafood is better. Which one should you purchase? What is the difference between wild and farmed seafood? Is one definitely better than the other? Suddenly this trip to the supermarket has become an ethical dilemma.

Common perceptions of the wild vs. farmed debate is that wild seafood is better because it contains more nutrients and tastes better than farmed seafood. While this seems like a logical argument -- is it actually true?

Wild seafood, from its namesake, is caught from the wild so their diet consists of natural prey. Farmed seafood is raised by farmers who grow them under specific conditions in a controlled environment. They are fed a specific diet and are confined in small pens.

Research has shown that due to the lack of small fish in their diet, farmed fish have lower omega-3 levels than wild fish. But farmed fish have been found to have a higher fat content than lean wild fish, giving them a softer and richer taste. Recent studies show that wild fish have far fewer cancer-causing contaminants than farmed fish. One possible explanation for this is that the farmed fish are fed food that contains antibiotics and cancer-causing chemicals. From the human health perspective, wild seafood looks to be the better of the two.

But there is more to the story than just taste and nutrition. The environmental impacts of fishing and fish farms is significant. Traditional fishing has a high carbon footprint, requiring a lot of fuel to get the ships out and back, as well as the transportation of the fish to markets. Overfishing is also a problem worldwide. For many reasons, including an effort to prevent the extinction of wild populations, people began the practice of farming fish and other seafood. This practice allows humans to still have the seafood options they want without depleting wild fish stocks.

Some farming techniques have been highly successful and even help clean up the ocean. Shellfish farming dramatically improves water quality by filter feeding. An oyster can clear over 15 gallons of water a day! Studies also show that farmed shellfish provide habitats with an abundance of organisms such as young fish and crabs.

But other farming techniques are much more harmful to the environment and consumers. Most of the world's shrimp farming occurs in southeast Asia’s mangrove forests. Mangroves are home to many aquatic animals and help to stabilize the shoreline. But the mangroves are cut down to establish more shrimp farms.

But what about the salmon you find in your local supermarket? Evidence shows that sea lice, which survive in high populations in salmon farms, are spread to nearby wild salmon. Overwhelmed by the huge populations of sea lice, the wild salmon, particularly the juvenile ones, are unable to survive the infestation and die. Sea lice has been a recurring problem in many countries and as a result, wild salmon populations have greatly declined. This paper was controversial because it did not investigate other factors that could have caused the decline in salmon populations. Researchers now claim that sea lice may be one of the factors that decrease farmed salmon populations.

A brief look at the issues shows there is no easy answer. For purchasing salmon, wild seems to be the best option today. But the answer changes with each species. Wild and farmed seafood both have their pros and cons from a consumer perspective and an environmental perspective. So next time when you’re at the grocery store trying to decide whether you should purchase wild or farmed seafood, don’t just look at the price tag. Consider how the product you are purchasing might affect more than just your stomach! Better yet, find some time to look into the specific issues on the production of your favourite seafood so you know what’s going on! A good place to start is http://www.seafoodwatch.org/.

Samantha Lui