Many of us love a good fish supper, and eating fish is something we can all too easily take for granted. According to the Food and Agriculture Organization (FAO), the average person eats twice as much fish as we did 50 years ago8, around 19k. a year. Typically, we rarely think about where our fish comes from, yet our seas are overfished1. As a result to meet demand, fish farming is becoming more prevalent. In this article, we explore the growth and types of fish farming out there and ask is fish farming sustainable?
Related read: Most Sustainable Fish & Responsible Seafood Choices.
Throughout past years, our fish have been caught in the wild by trawlers. They would essentially collect tons of fish using vast nets. Large-scale commercial fishing has essentially overfished certain species to meet increasing demand. So much so that FOA research shows that 90% of the world's fish stocks are fully fished, this, in turn, has resulted in declining fish stocks at sea for many species we enjoy eating.
The mass industrial scale of fishing in this way has caused us a number of other problems. It results in the needless death of smaller fish. Moreover, different, unwanted species get caught and killed unscrupulously among the catches.
Many countries have placed bans on fishing for certain species, and there are stringent quotas to endeavor to protect fish stocks. However, many wild-caught fish stocks have been dwindling, particularly with species such as cod7, whereby stocks have dropped by 31% since 2015.
So, in response to this situation, sustainable fish farming is helping to deal with the range of problems that have come with open water and traditional commercial fishing.
Today, fish farming has become a fast-growing industry as wild fish stocks have become depleted. Needless to say, the demand for fish remains high, and fish farming helps to fill the resulting gaps. Essentially, it is keeping up with demand and potentially taking over from mass industrialized wild fishing.
On the surface, sustainable fish farming is the farming of fish in an eco-friendly way that can sustain itself - allowing fish stocks to replenish without causing detrimental environmental harm. This also includes other marine life, such as mollusks, shellfish, and seaweed.
Whereas definitions can vary, for a fish farm to be sustainable, fish are grown in a healthy environment, avoiding the use of chemicals and the overuse of antibiotics5.
As such, they farm fish more naturally without using unsustainable practices to mass-produce fish quickly, including artificial means to expedite their growth.
Also known as sustainable aquaculture, there is a very fine line between sustainable farming and practices that are not so sustainable4.
Sustainable fish farms cultivate fish to minimize the environmental impact of more intensive agricultural processes. For example, the less sustainable fish farms, and many exist, might remove large quantities of water from natural reservoirs or lakes. Further, they can exit used water containing chemicals back into the environment. Or those at sea may introduce chemicals into the water that have a detrimental effect on nearby ecosystems.
Sustainable fish farms also manage fish waste sustainably, recycling, reusing, and discarding with environmental care.
Unlike fish farms that use unsustainable practices, the aquaculture systems of sustainable fish farms ensure that the fish remain healthy. To do so, they work hard to prevent damage to nature's ecosystems. They avoid using chemicals, additives, hormones, or antibiotics, which can cause further problems down the food chain.
Sustainable fish farms also take great care in what they feed their fish. They don't use animal protein as fish feed, and they do not use fish pellets that consist of animal waste byproducts. Using natural food stocks with the right balance of nutrients ensures fish grow naturally.
Most of us won't think twice about the water that fish are grown in. However, this is a very important aspect as sustainable fish farms responsibly use water. They ensure they actively monitor water quality and use a small surface area. This ensures that fish in the area and are native are not forced out of the area by farmed fish.
It is not just about growing the fish. Fish farms can produce a lot of waste, and sustainable fish farms treat waste responsibly. They use as much of the fish as possible, preventing parts that would otherwise go to waste from needing to be disposed of.
This will include the likes of fishmeal and fish oil or fish solids that we can use as animal feed or even as biodiesel. The pharmaceutical industry uses gelatin, in which fish skin plays a role. Moreover, it can also be used as an alternative to leather. Along with this, cosmetic manufacturers can also use collagen from the skin.
While many of us might think of fish farms as being located in open lakes or the ocean, that is not always the case. Many farms are now moving inland and are using land-based aquaculture operations6. This is a particularly useful way of managing demand in urban areas.
Along with this, some fish farms are heading out to the open ocean. Here, they can achieve an increase in sustainability due to cleaner water and predictable water flows that help reduce pests and waste9.
Sustainable fish farming can take many forms. However, the shared aim is to limit environmental impacts. What's more, it helps to support world resources. So whether it is farmed shrimp or salmon, there are different forms of fish farms.
Regarding sustainability, land-based farms could be better for the environment. Farming fish on land helps make it possible to contain chemicals and waste.
The downside is that land-based farms must recreate a healthy natural habitat through tanks and filtration. There is an environmental overhead to running all the machines, with the more sustainable fish farms powering their endeavors using renewable energy such as solar or wind.
Bottom of off-bottom culture, fish farms make use of the natural habitat3. They use large trays to grow them on the seabed, or they can be grown using floating mesh nets. This is perfect for fish farmers growing shellfish such as oysters or mussels.
These farms are now becoming more apparent in the open ocean. Perfect for farming practices involving large amounts of fish, space is abundant, too. They also provide a specific level of sustainability. The water is clean, which is healthier for the fish, while the currents provide a natural habitat while washing away pests and waste.
However, the problem exists of non-native or invasive fish escaping from open ocean farms. A study from Norway found that 92% of the recorded escape of Atlantic salmon and rainbow trout came from farms in the ocean2, usually due to holes in netting or equipment failure.
Growing Cobia, Open Blue Sea Farms is the biggest open-ocean farm in the world. The farm hatches fish eggs in a hatchery and then moves them into vast pens that they position deep beneath the surface for 14 months. The waters are clean, and the fish thrive on this farm off the coast of Panama.
This project considers the ability to farm fish by using an Aquapod that they attach to a boat that drifts in deep water. They've also experimented with barges in the ocean to which an Aquapod is attached. The aim is to add propellers as well as a GPS system potentially. The barge can transport farmed fish to the next phase of the process by being self-propelled.
One of the crucial aspects of any fish farm is the food they are fed. In the past, unsustainable methods were problematic for the environment. Despite this, Kampachi Farm has been experimenting with fish diets. They have fed their fish using soybeans and plants and have always fed them a diet with no fishmeal. All of these experimental diets were similar to that of a regular diet.
Along with this, fish food made from corn, wheat, and soy has also been developed. They were able to replace the fish oil using fatty acids from algae as well as amino acids and soybean or canola oil. As a result, they found that the levels of PCB and mercury were lower than in those fish they gave a fishmeal diet.
In 2010, WWF in the Netherlands and the Dutch Sustainable Trade Initiative came together to create the Aquaculture Stewardship Council (ASC). Today, ASC certifies farmed seafood as sustainable and champions the standards required to ensure our farmed fish ends up on our plates with environmental and social responsibility.
Our need for fresh fish is still on the rise. However, the supply cannot keep up with demand unless we want to deplete stock levels and harm the environment when producing food for our growing populations. Therefore, sustainable fish farms could be the way to go.
While improvements have been made, there is still a long way to go. This is particularly true in ensuring we can scale it up to meet demand. However, sustainable fish farming can only be successful if consumers know how to eat sustainable fish.
As methods and practices improve significantly, consumers also have to play a role.
They can find out where and how they caught the fish. Identifying this on labels or by asking the fishmonger when purchasing from a fish market is possible.
We can also look out for sustainable fish choices, such as haddock instead of cod. From sustainable fish farming to making better choices, there is a lot that we can do to ensure we take care of our ocean and our fish and continue to enjoy fresh fish as consumers.
|Stergiou, Konstantinos. (2002). Overfishing, Tropicalization of Fish Stocks, Uncertainty and Ecosystem Management: Resharpening Ockham's Razor. Fish. Res.. 55. 10.1016/S0165-7836(01)00279-X.|
Heidi Moe Føre, Trine Thorvaldsen, Causal analysis of escape of Atlantic salmon and rainbow trout from Norwegian fish farms during 2010–2018, Aquaculture, Volume 532, 2021, 736002, ISSN 0044-8486, https://doi.org/10.1016/j.aquaculture.2020.736002
|Influence of suspended and off-bottom mussel culture on the sea bottom and benthic habitats: a review. Christopher W. McKindsey, Philippe Archambault, Myriam D. Callier, Frédéric Olivierd. Ocean and Environmental Sciences Division, Maurice-Lamontagne Institute, Fisheries and Oceans Canada|
|Lazard, J., Baruthio, A., Mathé, S., Rey-Valette, H., Chia, E., Clément, O., . . . René, F. (2010). Aquaculture system diversity and sustainable development: Fish farms and their representation. Aquatic Living Resources, 23(2), 187-198. doi:10.1051/alr/2010018|
|Romero, Jaime & Feijoo, Carmen & Navarrete, Paola. (2012). Antibiotics in Aquaculture – Use, Abuse and Alternatives. 10.5772/28157.|
|Yossi Tal, Harold J. Schreier, Kevin R. Sowers, John D. Stubblefield, Allen R. Place, Yonathan Zohar, Environmentally sustainable land-based marine aquaculture, Aquaculture, Volume 286, Issues 1–2, 2009, Pages 28-35, ISSN 0044-8486, https://doi.org/10.1016/j.aquaculture.2008.08.043|
|Lindegren M, Diekmann R, Möllmann C (2010) Regime shifts, resilience and recovery of a cod stock. Mar Ecol Prog Ser 402:239-253. https://doi.org/10.3354/meps08454|
Food and Agriculture Organization of the United Nations (FAO). The State of World Fisheries and Aquaculture 2020. Rome
|Benetti, D.D., Benetti, G.I., Rivera, J., Sardenberg, B., & O'Hanlon, B. (2010). Site Selection Criteria for Open Ocean Aquaculture.|
Jen’s a passionate environmentalist and sustainability expert. With a science degree from Babcock University Jen loves applying her research skills to craft editorial that connects with our global changemaker and readership audiences centered around topics including zero waste, sustainability, climate change, and biodiversity.
Elsewhere Jen’s interests include the role that future technology and data have in helping us solve some of the planet’s biggest challenges.