Is aquaculture a good alternative to fishing?

As scientists and environmentalists look for innovative alternatives to fishing—while still meeting the global demand for fish as a source of food—some have said we should turn to "aquaculture." Rather than catching fishes in the wild, why not raise them in captivity, the same way terrestrial farms raise poultry, pork, and livestock for slaughter? But just what does aquaculture entail? Is it humane? And is it really a path toward a more sustainable food system?

What is aquaculture?

The National Oceanic and Atmospheric Administration (NOAA) defines aquaculture as the breeding, rearing, and harvesting of fish, shellfish, and aquatic plants in all types of water environments.

In other words, it's underwater agriculture, or "fish farming." The aquaculture industry raises fishes and other aquatic organisms in controlled environments, specifically for human consumption. In fact, there's a good chance that the seafood in your local grocery store came from aquaculture. The United Nations' Food and Agriculture Organization (FAO) reported in 2020 that half of the world's fish, crustacean, and mollusc supply was farmed rather than caught in the wild.

When did aquaculture start?

While the industry has grown substantially in recent years, aquaculture is certainly nothing new. Historical records show that Ancient Chinese societies raised and harvested fishes and underwater plantlife thousands of years ago. Writings from ancient Rome and Egypt reveal that they too raised fishes in carefully controlled ponds—sometimes as a food source, sometimes as a display of wealth.

In the US, commercial aquaculture didn't come about until the mid-1800s, with the production of rainbow trout. Large-scale trout production developed later, during the 1950s, in the Western US.

Today, fish farming is more prevalent than it has ever been. Between 1997 and 2021, global aquaculture production more than tripled worldwide.

Types of aquaculture systems

Freshwater aquaculture

As the name suggests, freshwater aquaculture takes place in bodies of freshwater, such as manmade ponds, lakes, and rivers. Freshwater fish farmers most commonly raise carp from China, and catfish and trout from the US. However, any freshwater-dwelling organisms may be cultivated in these environments, including crustaceans, reptiles, amphibians, and plants.

Marine aquaculture

Marine aquaculture is the "breeding, rearing, and harvesting" of aquatic species that live in the sea. Farming can take place in oceanic cages, on the seafloor, in saltwater ponds, or tanks. According to NOAA, farmed seafood products make up half the world's seafood supply. China, Norway, and Vietnam dominate this market by occupying the top three spots for highest annual seafood exports. The vast majority of the most popular seafoods in the US—such as shrimp, tilapia, salmon, and clams—are imported from somewhere else.

Brackish water aquaculture

Also known as "coastal aquaculture," brackish water aquaculture refers to the cultivation of organisms found in bodies of water that are saltier than freshwater, but less salty than ocean water. Fishes, crustaceans, and plants found in estuaries—the area where a freshwater river or stream meets the ocean—may be reared and harvested through brackish water aquaculture.

Most commonly farmed fish species

Atlantic Salmon

The fastest growing food production system in the world, farm-raised salmon production in 2020 accounted for 32.6 percent of all marine and brackish water finfish. The term "finish" distinguishes "true fishes" from other forms of aquatic life who have "fish" in their non-scientific names, such as jellyfish, crayfish, and shellfish.

Tilapia

A once "obscure" fish native to Africa, tilapia has quickly risen to become one of the most farmed and widely consumed fishes in the world. The aquaculture industry refers to tilapia as the "aquatic chicken." This comparison is sadly apt. Fish farmers force tilapia into overcrowded conditions and feed them cheap, innutritious food to make them gain weight quickly. Factory farms on land use the same inhumane tactics to raise chickens for meat.

Carp

Not only one of the most common of farm-raised fishes, carp are also likely one of the oldest. In 2019, a group of scientists analyzed ancient fish bones and concluded that "managed agriculture of common carp" was present in Henan Province, China as early as 6,000 BC-8,000 years ago.

Catfish

The catfish was one of the first commercially farmed fishes in the US, and they have gone on to become one of the most popular too. The industry continues to grow,particularly in the South. Mississippi, Alabama, Arkansas, and Texas account for 97 percent of total US catfish sales, which added up to more than $420 million in 2021.

Rainbow trout

Another staple of modern aquaculture, rainbow trout are known as "the farmer's fish%20and%20seawater.)," because of their quick growth cycles and their ability to adapt to different environments around the world. Rainbow trout are so versatile, in fact, that some in the wild will migrate from freshwater to saltwater, and change their bodies to survive in this new habitat.

Benefits of aquaculture

As aquaculture becomes a more relevant element of the global agricultural industry, experts have explored the ways that sustainable, responsible fish farming can alleviate issues like food insecurity and overfishing.

Aquaculture comes with its own set of concerns too, however. Scientists are only just beginning to more fully appreciate the depth of fishes' sentience, and therefore the need for stronger welfare protections on fish farms. And because aquaculture fishes need to eat too (especially since many species are carnivorous), researchers have questioned how efficient fish farming really is. In other words, do the resources required for aquaculture production outweigh the amount it yields? Farms have made changes to feed ingredients in recent years to give farmed fishes more plant-based, sustainable diets. And yet, a 2019 report found that 20% of all wild-caught fishes were still being used to feed farmed fishes.

It's always important to remember that the best way to eat in a sustainable, humane way is by adopting a plant-based diet. Researchers from around the world are in agreement that switching to a vegan diet is the "single biggest way" to reduce our own environmental impact. In fact, in a 2020 report on climate change mitigation, the UN recommended a diet of nuts, legumes, fruits, and vegetables instead of animal products. Veganism, the report stated, lowers our carbon footprint, eases the burden on forests exploited for animal feed, and preserves biodiversity throughout the globe.

And if that's not convincing enough, a plant-based diet can promote weight loss, reduce the risk of heart disease, and lower your chances of getting certain types of cancer.

By keeping fishes and other animals off our plates entirely, we can fight animal cruelty, mitigate our own environmental impact, and improve our health too.

Environmental concerns with aquaculture

Pollution

It's not easy to keep water contained to one location. When water from a fish farm flows into a larger, natural body of water, the additives and byproducts of aquaculture come with it. "Nutrient pollution".) is one of the top environmental concerns associated with aquaculture. When uneaten feed and fish waste from a farm seeps into the surrounding environment—something highly likely in open-net cages—it can cause toxic algae to bloom and change the chemical properties of the nearby sediment.

Aquaculture farms can also lead to chemical pollution. Like terrestrial farms, many fish farms use antibiotics and other medicines to try and prevent the spread of disease in their overcrowded pens. One study found that up to 80 percent of antibiotics given to farmed fishes as medicated feed is lost to the surrounding marine environment around the farming sites.

Habitat destruction

Related to aquaculture pollution, if an ecosystem near a fish farm becomes too nutrient-rich, it spurs a process called eutrophication. Eutrophication, in short, occurs when nutrient-rich waters cause an overgrowth of algae, which blocks sunlight, killing off the area's plantlife.This sets off a chain reaction in the entire ecosystem, taking away food sources and destroying the natural habitat for fishes and other animals who once lived there.

Spread of disease

Similar to factory farms on land, aquaculture sites, especially marine farms, that crowd fishes into close proximity to one another are bound to facilitate the spread of disease. The issue is most troubling in ocean-based, open-net facilities and cage-culture structures in large bodies of freshwater. Wild fishes may swim freely into a pen and "intermingle" with diseased, farmed fish. On the flip side, farmed fishes can also escape into the wild and spread disease.

Welfare concerns with aquaculture

Despite the growing scientific consensus that fishes feel pain, emotions, and stress, there is still a troubling lack of consensus throughout the aquaculture industry about how to ensure the humane treatment of fishes on farms. In a 2019 report, the FAO stated, "It is not well-understood to what extent welfare concepts and definitions as they have been developed for common warm-blooded farm animal species can be applied to fish... As a consequence of the limited knowledge of and the diversity of cultured species, relatively few operational welfare indicators for farmed fish have been validated to date."

The Fish Welfare Initiative, a relatively new organization dedicated to promoting the humane treatment of fishes, reports a range of welfare shortfalls on fish farms that mirror the same problems commonly seen on industrial chicken, pig, and cow farms.

Aquaculture is simply rife with welfare issues. Overcrowded pens increase stress and aggressive behavior in fishes, not to mention exposing them to disease and poor water quality. Meanwhile, a lack of regulations for humane slaughter methods have led many fishes to die painfully through asphyxiation.

How governments are regulating aquaculture

With so many aquaculture facilities throughout the world, there are many different laws regulating how a fish farm operates within its own country.

China, the global aquaculture leader, has no stand-alone animal welfare legislation at a national level. However, the Fish Welfare Institute reports that there are reasons to be optimistic, such as the inclusion of animal welfare in high school biology curriculum as well as China's participation in the World Conference on Farmed Animal Welfare in 2017.

Norway, the next major player in the marine aquaculture industry, purports to have the "strictest aquaculture regulations in the world," specifically regarding the health of farmed Atlantic salmon, one of its prime exports. Norway has called on other salmon-farming countries, like Scotland, Canada, and Ireland to follow suit and adopt similarly stringent regulations.

In the United States, aquaculture is regulated through a variety of agencies including the FDA, USDA, and EPA. Aside from the National Aquaculture Act of 1980, which defined aquaculture and established a national development plan, federal regulations rarely address aquaculture directly, and instead rely on adjacent laws, like the Clean Water Act or the Animal Drug Availability Act, to enforce quality standards.

It's important to remember that under US law, fishes are regarded as property, and not afforded the rights that sentient, living creatures ought to be afforded. Additionally, the Humane Slaughter Act does not include protections for fishes, despite the fact that trillions of them are slaughtered worldwide every year.

The bottom line

While sometimes presented as a solution to overfishing and other environmental issues, aquaculture presents its own deeply concerning problems regarding the industry's environmental impact and detriment on fish welfare. If you are looking for a way to promote the humane treatment of animals and a more sustainable, plant-based lifestyle, you can join a community of like-minded animal activists from around the world through The Humane League's Fast Action Network.

If you're ready to unleash the power of this community and amplify your impact for animals, join us today.