Is Fish Farming Sustainable?

Jane Marsh - December 13, 2022

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With the global population expected to reach 9.8 billion people by 2050, it’s become more critical than ever to find a viable solution for preventing future food scarcity. 

Climate change has expelled its wrath on land and water while driving dire consequences on the agricultural sector. Experts believe that if society continues the same food production methods in the coming years, there will only be enough food to feed half of the growing population.

Fish farming—also known as aquaculture—accounts for 17% of edible meat production worldwide. However, researchers suggest there will need to be a 36% to 74% increase of current yields to ensure people have a viable food source later on. 

What does that mean for a sustainable seafood supply, though? While fish farming practices have gone on for hundreds of years, we need to consider aquaculture’s many pros and cons as an endurable source of protein. 

Something Fishy: Current Problems in Aquaculture

The aquaculture industry is already fraught with criticism and accusations of overfishing and overexploitation of marine wildlife. The National Oceanic and Atmospheric Administration (NOAA) estimates that 55% of fish stocks are overfished in American fisheries. 

Globally, that statistic is grimmer. According to the United Nations Conference on Trade and Development (UNCTAD), 90% of the ocean’s fish stocks have been overharvested, fully exploited and depleted. 

Yet, several other factors deem fish farming as unsustainable worldwide. Here are three growing concerns surrounding aquaculture.

1. Environmental Impact

The environmental impact of fisheries is especially troubling for nearby habitats. Fragile ecosystems, such as mangrove forests, undergo significant degradation in some regions due to unsustainable fisheries. There is also an increased chance for invasive species and an impaired gene pool for wild fish populations. 

Non-native or invasive fish species often escape from aquaculture farms. While there is limited statistical information about escaped fish, the ecological consequences can significantly alter marine biodiversity through rapid breeding and competition for food and habitat. Like land-based invasive species, when an invasive fish species overtakes a particular habitat, the impacts on biodiversity are usually irreversible and damaging.

Escaped farm-raised fish also typically breed with wild fish, resulting in weakened genetics and offspring struggling to survive. For example, in one study, Atlantic salmon escapees from Norwegian fisheries had a lower genetic transfer and survival rate over 20 years, decreasing overall healthy Atlantic salmon populations in that region.

2. Increase in Marine Waste

Of course, fish farming isn’t exactly known to be the cleanest food production method. An excess of marine waste often derives from aquaculture feed, chemicals, feces, and pathogens.

Regarding feed, quantity often supersedes quality in aquaculture. Although fish rely on a high-quality food source to maintain their vitality and size, many fisheries lack a nutritionally-balanced, organic feed. This results in increased mortality rates and toxic feces released into the pens. 

Unfortunately, dead fish are also often tossed back into the ocean. In warm temperatures, fish skin, bones and shells biodegrade, causing increased bacteria and severe environmental and human health risks.

While stringent laws restrict the amount and type of chemicals used in fisheries, some fish farms treat their fish with medications, disinfectants, and antifoulants to control parasites and infections, prepare ponds for new fish production and maintain current fish populations. Despite regulations on drugs and chemicals, the accumulation of substances can be detrimental.

3. An Influx of Sea Lice and Other Pests

Fisheries are most commonly susceptible to sea lice and pests that stunt fish growth and lead to disease and death within fish populations.

Sea lice grasp onto the host as larvae and feed on the fish. While aquaculturists have the means for grappling minor cases of sea lice, larger infestations could lead to mass population loss and more widespread infections. 

Parasites and other pests have dire effects on fish farming, as well. It’s not uncommon for fish to have reduced reproductive capabilities and decreasing growth rates when exposed to parasitic diseases. As a result, fisheries worldwide suffer substantial economic losses when this situation occurs. 

Innovations in Sustainable Fish Farming

Several aquaculture companies are developing advanced technologies targeting the fishery industry. Their hope: To make the practice more sustainable for the future. 

From providing a healthier, organic fish feed to mitigating sea lice, fresh innovations allow fish farmers to control their stocks and prevent the spread of disease and death.

1. Software Imaging for Managing Sea Lice

Camera software from companies like Aquabyte and Ecotone makes it possible for aquaculturists to view their fish pens, accurately count the prevalence of sea lice and determine the health of their fish. 

In practice, Ecotone’s SpectraLice camera can take images of up to 2,000 salmon within 24 hours, unlike manual counting, which may limit farmers to reading only 10 to 20 fish per week. 

With advanced imaging technology, aquaculturists can develop adequate solutions for fishery management. They can also mitigate the spread of parasites and infections before it becomes a more significant issue. 

2. Sustainable Aquafeed

Studies indicate that an estimated 73.15 million tons of aquafeed are required to meet fish stock production levels. As such, a sustainable feed with a nutritionally-balanced and eco-friendly composition is necessary. 

Currently, biotechnology company Calysta has developed FeedKind—a naturally-fermented fish feed using zero natural gas, crops, or water during production. Early trials of FeedKind show promising results, including a positive impact on yellowtails’ diet and growth performance after 30% of traditional fishmeal protein was replaced with the non-genetically modified food. 

Additionally, shrimp populations exposed to early mortality syndrome (EMS) had a 100% survivability rate after 15 days of being fed FeedKind.

Plant-based feed is another avenue towards sustainable aquaculture, currently valued at $6.8 billion, with an anticipated increase of 6% through 2032. Soybean and corn meal-derived feed is particularly cost-effective and can be mass-produced for future aquaculture practices.  

3. Off-Shore Fisheries

Traditionally, the aquaculture sector has conducted itself along coastlines where waste, pests and fish farm escapees have negatively impacted local ecosystems. However, some companies are now experimenting with offshore fisheries in open seas. 

Research suggests that open-ocean fisheries could increase fish and shellfish yields from 36% to 74% by 2050. The SalMar Group developed one of the world’s most extensive open-water fish pens that can hold 1.5 million salmon at once. Known as the Ocean Farm 1, it operates approximately three miles off the coast of Norway.

Additionally, Ocean Arks Tech of Chile (OATECH) is in the process of constructing a massive vessel of self-cleaning fish pens using low-emissions artificial intelligence. 

Offshore farms are promising innovations for maintaining healthier fish stocks and practicing more sustainable aquaculture. Because the open ocean has larger currents, there will likely be fewer parasitic infestations and genetic compromise through interbreeding. Fish can also swim to deeper depths in these pens rather than gathering near the surface to feed. 

Global Food Supplies Depend on Sustainable Fish Farming

Considering how over 3.3 billion people get their daily protein intake from seafood, finding solutions to fish farming is essential. Although fish farming may not be entirely sustainable during current operations, fish farmers worldwide are implementing these new technologies and improved aquaculture practices to generate ample stock populations and feed the growing population—especially those living in developing countries. In the end, combatting future food shortages may very well depend on more sustainable fish farming. 

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About the author

Jane Marsh

Starting from an early age, Jane Marsh loved all animals and became a budding environmentalist. Now, Jane works as the Editor-in-Chief of Environment.co where she covers topics related to climate policy, renewable energy, the food industry, and more.