Supporting Sustainable Seafood: Part 2
Last Updated on March 29, 2021
Farmed Seafood vs. Wild Caught
Welcome to Part 2 of the Sustainable Seafood series! Last time, we dove deep into why we need to support sustainable seafood. But even if the seafood is marked as “sustainable,” you may notice the “farmed” or “wild caught” labels alongside it. What’s the difference? Is one better than the other?
There’s currently a lot of debate and conflicting information around which one is actually healthier or more sustainable. It can get pretty convoluted! However, when contemplating the merits of farmed seafood vs. wild caught, it ultimately depends on the type of seafood itself, and the way it was harvested.
If that seems a bit fishy to you, let’s break it down to help you make the best decision – for you, for the fish, and for our planet.
Farmed Seafood – What is it?
Currently, about 50% of our seafood comes from farmed sources, and number is expected to grow! In fact, according to the World Wildlife Fund (WWF), farmed seafood is “the fastest growing food production system in the world.” But what is it? How do you farm fish?
Fish farming, also called aquaculture, is way of hatching and raising fish. It can happen in oceans, rivers, and lakes, and even on land in raised tanks. The process starts in hatcheries, where they breed the fish. Then they go off to the farms where they are raised until they are processed for your plate. The most common types of farmed seafood are salmon, shrimp, and mussels.
Farmed seafood is especially important at a time when our oceans are filling with more plastic, and fewer fish. But only if it’s sustainable, of course! Sometimes fish farms can lead to disease, chemicals, and excess nutrients in the water, or escaped fish impact the surrounding ecosystem. That being said, some farming methods reduce those risks while still producing quality seafood.
Sustainable Fish Farming Systems
Recirculating systems: Fish are raised in a closed tank system where the water is treated, then recycled back through the tank. It reduces wastewater, removes diseases and parasites, and can be used for many different types of fish. And because there are barriers to prevent escape, the fish can’t mingle with the outside environment.
Suspended systems: Shellfish grow on suspended ropes, nets, and trays that float in the water. Since these are filter feeders, there is very little waste created, and they actually clean the water. As long as the farmer is raising native species, this method is very low risk.
Raceways: Flowing water is either diverted from a natural source such as a stream, or recirculated. If there are proper barriers in place to prevent escapees and the wastewater is treated, this can also be a low risk closed-system.
Fish Farming Systems to Avoid
Open net pens & submersible net pens: This system encloses farmed fish in net systems, within a larger body of water (such as the ocean or a lake). While the fish can swim freely inside their pens, the waste, disease, parasites, and chemicals flow out and into the environment. There is also a chance of the farmed fish escaping and interbreeding with wild populations, or outcompete for food and space.
Ponds: Fish are farmed within enclosed water bodies. Without proper management and treatment systems, pond wastewater will be a major source of pollution to the rest of the pond. Ponds can also cause habitat destruction, like how shrimp farms in Southeast Asia are impacting the mangrove forests.
Wild Caught Seafood – What is it?
Wild caught seafood is, as you might have guessed, seafood that is caught (not raised). These fisheries exist in the ocean, in lakes, and in rivers and ponds, depending on the type of fish. But with 90% of wild fish stocks overfished or fully exploited, not all wild caught seafood is equal.
Wild fisheries need close management so they can ensure the fish stocks have the chance to maintain healthy levels. They also need the fishers to take care to only catch what they are fishing for, and not damage or disrupt their ecosystem.
Sustainable Wild Caught Methods
Pole & line; Trolling: This is your standard fishing rod with a single hook at the end of the line. Trolling often has multiple moving lines. The fishers can only catch one fish at a time, and any unwanted catches can be released back.
Pots: These are underwater traps that hold shellfish like lobster and crab alive until the fisher returns to collect them. If unwanted fish get in, they can be released alive, or smaller fish can escape through a second opening. It’s important these aren’t abandoned or lost, because they can continue to capture fish without ever being retrieved.
Handlines; Jigs: Similar to pole & line, handlines and jigs are handheld methods that only catch fish one at a time. There is almost no chance of bycatch or habitat destruction.
Harpoons: Again, these target one fish at a time, meaning low risk of bycatch.
Wild Caught Methods to Avoid
Gillnets: This is a wall of nearly invisible netting, floating vertically in the water, that traps fish who swim into it. Sometimes loud noises are used to scare fish and drive them towards the net. While there are ways to reduce this risk, improperly equipped gillnets can trap other animals like turtles and sharks.
Bottom Trawls: This method takes a large cone-shaped net and drags it along the ocean floor to catch bottom dwellers. I’m sure you can imagine just how much bycatch ends up in these nets, not to mention the habitat destruction that goes along with it. It has has an enormous effect on carbon emissions! A recent study found bottom trawling releases as much carbon as air travel.😱
Dredges: Dredges are similar to bottom trawls, only it is a metal basket that is used to scrape up shellfish buried below the ocean floor. Again, there is a major risk of bycatch and significant damage to the seabed habitat.
Purse Seines: Like a drawstring purse, fishers use a large net to encircle schools of fish, then pull it closed. Sometimes special objects are used to attract the schools to the middle of the net. But this also attracts other marine life which can get caught up in the net as well.
So What’s the Better Choice?
It depends on the type of fish, the method used, and sometimes even where it was harvested.
Not to worry! As long as you are committed to buying certified sustainable seafood, you can be sure that no matter whether farmed or wild caught, your purchase is supporting the future of our aquatic ecosystems. Don’t be afraid to ask your grocery store or favourite restaurant how they source their seafood either. Their answer will either help you decide on your meal, or maybe spark a much larger conversation that will get them thinking sustainably as well.
Up next in the Sustainable Seafood Series, we’ll take a look at some of the o-fish-al Sustainable Seafood guides. Basically, what they are and how to use them to make a better choice seafood. Stay tuned!🎣