Wild-Catch Fishing vs. Aquaculture: Which Is More Sustainable?

If you’re looking to eat more sustainably, you might be wondering if wild-catch fishing or aquaculture is better for the environment. The answer? It’s complicated. 

Wild-Catch Fishing

Fish is one of the only major food sources people still harvest regularly from the wild. There are numerous benefits to wild-catch fishing. Unlike fish farming, it doesn’t require the use of any extra water or space to be set aside. 

Wild fish require very few additional resources before being harvested. They spend their lives eating a natural diet, and, compared to other animals like cows or pigs, they’re very good at converting food into meat. They provide a relatively accessible protein source — in fact, fish is the most commonly consumed meat worldwide, with people eating 160 million metric tons of fish in 2021. 

However, wild-catch fishing has a lot of drawbacks. For one thing, fishing boats are a significant source of greenhouse gas emissions. Some types of fishing operations are worse for the environment than others. Shrimp and lobster boats, for example, emit more carbon because they have to travel long distances between traps and stop frequently. 

That doesn’t take into account the greenhouse gas emissions from shipping the fish to consumers. The longer the road from sea to plate, the more pollution is emitted along the way. 

Additionally, wild-catch fishing can directly damage ecosystems. Net trawling results in a lot of bycatch — the term for any animals caught by mistake. In fact, bycatch rates can be over 29% in some areas, and most of the animals are dead by the time fishermen throw them back. Accidentally caught species include turtles, dolphins, manatees and seabirds as well as unwanted fishes. 

Bottom trawling is infamous for causing ecological destruction. By dragging a weighted net along the ocean floor, fishermen destroy corals, anemones, sea urchins, worms and other animals living on the seabed and catch species indiscriminately. Coral forests can take centuries to regrow after being destroyed. 

Hook-and-line fishing is a more environmentally friendly commercial fishing technique. It consists of using a long string of fishing line with multiple branches and baited hooks to selectively catch target species. It’s much better for catching the intended species — and the intended size of the fish — than other fishing methods. 

Aquaculture 

Also called fish farming, aquaculture involves raising fish either in tanks or in pens directly in the water. Roughly 50% of the fish people eat comes from fish farms. From an emissions standpoint, producing more farmed fish would be better for the Earth than raising more beef, because fish are more efficient at converting food to meat than cows. 

In fact, shellfish can even improve local water quality because they’re filter feeders. Controlling fish’s diet by farming them also ensures they don’t eat heavy metals, like mercury, that they might encounter in the wild. 

However, raising fish in natural bodies of water poses some problems. If the fish escape into a non-native environment, they can become an invasive species and compete with native fish populations. Additionally, the extra nutrients in the water around fish farms — which comes from fish food and waste — can build up over time, leading to algal blooms that deplete oxygen levels in the surrounding water. 

Fish farms can also harbor disease due to the number of animals kept in close confinement. Aquaculturists often give fish antibiotics to treat infectious outbreaks, and the medicine can diffuse into the water. Eventually, this problem may promote the growth of antibiotic-resistant bacteria in the water near fish farms. 

Aquaculture can damage the surrounding ecosystem in other ways. In Indonesia, for example, developers are tearing down mangrove forests to make room for additional shrimp farms. Many fish farms require a lot of energy input to heat the water, create circulation or dispense food, and this often comes from fossil fuels. 

Lastly, some species of farmed fish — such as salmon — are carnivores. Aquaculturists sometimes feed them wild-caught fish species, which defeats the purpose of farming fish in the first place. 

Can Fish Be Sustainable?

Both wild-catch fishing and aquaculture can be environmentally friendly. Raising fish in inland tanks prevents the spread of disease, antibiotics and invasive species. Rather than reacting to disease outbreaks as they occur, aquaculturists can give fish vaccines to prevent disease. 

Developers can build coastal fish pens in areas with high currents. Doing so helps wash away extra nutrients from fish feed and waste. Or, instead of draining fish waste into the ecosystem, farms can build better waste management systems to clean and treat the water first. Fish farms can receive certifications to demonstrate that they’re using sustainable practices.

Although fish farming plays a large role in meeting the world’s protein requirements, it’s not productive enough to satisfy the large demand for seafood. Therefore, wild-catch fishing needs to become more sustainable. 

The National Oceanic and Atmospheric Administration (NOAA) sets regulations for commercial fishing in the United States. The NOAA’s rules ensure fisheries prevent overfishing, rebuild depleted stocks, minimize bycatch, conserve fish habitat and consider social and economic impacts on fishing communities. It uses scientific monitoring and regional management to enforce these laws at U.S. fishery sites.  

How to Buy Sustainable Fish

First, try to avoid the most common fish species, including tuna, cod, salmon and haddock. Look for fresh, unpackaged, local fish if you live near a body of water that supports fishing. 

If you live in the United States or Canada, peruse the Monterey Bay Aquarium Seafood Watch Guide to see which fish to choose and which to avoid. It lists the species that come from well-managed fisheries or aquaculture operations, those that cause some concern and those that come from an environmentally damaging industry.

Other labels and certifications to look for include those from the Global Aquaculture Alliance’s Best Aquaculture Practices, Aquaculture Stewardship Council, Marine Stewardship Council and Friend of the Sea. 

Diving Into the Fishing Industry

Wild-catch fishing and aquaculture both have the potential to be sustainable. There’s no black-or-white answer as to which is better, since the methods used to raise or catch fish vary so much around the globe. 

Ultimately, consumers need to be careful when buying seafood to make smart purchasing decisions, because — when you get right down to it — there are no longer plenty of fish in the sea.