Pros & Cons Of Aquaculture & Fish Farming

In this guide, we outline the pros and cons of aquaculture and fish farming.

We focus mainly on the farming of fish, crustaceans and bivalves in both land based and ocean based farming operations.

 

Summary – Pros & Cons Of Aquaculture & Fish Farming

Fish farming and agriculture can be an important method of food production to provide nutrients and protein to a growing population, and in some ways can be a sustainable fishing practice

Overall, aquaculture and fish farming has been used in some capacity for 1000’s of years

However, production from fish farming has significantly increased over the last few decades to the point it matches or outpaces some forms of wild caught fishing and land based conventional agriculture

Various advances and developments are helping to improve fish farming in several ways

The impact and pros and cons of fish farming are nuanced and depend on several variables such as the type of fish farmed, where they are farmed, how they are farmed, the type of feed used (especially the % of fish meal, fish oil, and vegetarian ingredients used in the feed), the breeding rate of the fish, and the resources used (such as water, electricity, and more)

More sustainable types of fish farming do exist, and it would be worth looking more into these types of fish farming, and seeing how they can match up with the economic profit motive, being able to scale to meet demand, and the well being of the fish being farmed

 

Pros

Problems with pond based aquaculture can be managed with proper site selection, proper management of soil and water quality [and proper management of the fish culture]

The environmental and sustainability impact of aquaculture can be dependent on controllable factors, and there are some clear solutions to past problems

Some farmed fish can be raised on vegetarian meal/feed

Is a way to increase the food supply for the human population that doesn’t rely sufficient wild animal population numbers 

Aquaculture can be profitable as a business

The outlook for aquaculture looks favorable

Aquaculture shows potential to improve in the future terms of production and technological advances, as well as sustainability

Conversion efficiency can be high compared to other types of meat

Might have a higher chance of being free of environmental contaminants

In some cases, aquaculture can increase water quality

Can be used as a form of small business in lesser developed regions

Fish waste can sometimes be used for crop fertilization

 

Cons

Good management may not prevent technical difficulties with aquaculture

There can be practical problems with pond based aquaculture

Some farmed fish need wild fish as feed, and it can be resource inefficient when considering feed to production conversion

The resource footprint of aquaculture can vary

There’s potential waste and waste pollution to consider with fish farming

Fish farming can use forage fish species, which can undermine marine food webs

Can result in disease, abandonment habitat destruction

Disease transfer from farmed fish to wild fish is a potential problem

Farmed fish escaping into the wild environment might be problematic

There can be a conflict of interest between production at scale, meeting demand, running at profit and the comfort of the fish

Some slaughter methods are can be considered to be inhumane

 

*Note – this is a general guide only.

Obviously the real pros and cons of fish farming and aquaculture depend on the fish (or water organism) being farmed, how they are farmed, the processes used, and other variables.

 

What Is Aquaculture and Fish Farming?

The nature.com resource listed does a good job of outlining what aquaculture and fish farming is.

To paraphrase:

– It can involve the production of aquatic organisms, which includes fish, mollusks, crustaceans, algae and plants

– There’s a number of strategies that are used, and the different systems come under the category of either extensive or intensive production

– Under the extensive or intensive production banner, there’s earthen ponds, raceways, cages, net pens, and recirculating systems

– Farming systems can be created, or placed into exiting ocean or land based water bodies

 

Per treehugger.com:

It can involve freshwater or saltwater fish, plants, or other life forms, and the reasons might be commercial … or they might be environmental or research-based

 

Some Of The Most Farmed Fish In The World

Per wikipedia.org:

Worldwide, the most important fish species produced in fish farming are carp, tilapia, salmon, and catfish

China provides 62% of the world’s farmed fish

 

Pros Of Aquaculture & Fish Farming

Problems with pond based aquaculture can be managed with proper site selection, proper management of soil and water quality [and proper management of the fish culture]

[This can contribute to] growing healthy fish, achieving satisfactory production and improving culture efficiency [as well as] high yield and profit (researchgate.net)

 

The environmental and sustainability impact of aquaculture can be dependent on controllable factors, and there are some clear solutions to past problems

… the environmental impact of aquaculture is completely dependent upon the species being farmed, the intensity of production and the location of the farm.

Additionally, new strategies and technologies have emerged and have proven that it is possible to have sustainable aquaculture. [Ultimately, environmental and sustainability based impact can be nuanced]

[siting fish farms in waters with strong currents, paying attention to the density of fish in an area, recognizing the potential benefits of land based aquaculture on ecosystems over aquaculture farmed in natural water sources like the ocean where environmental problems can be more prevalent, declining antibiotic use, and using cameras and inspecting enclosures for escape points – can all decrease the environmental and sustainability impact of fish farming]

– aquaculturealliance.org

 

In some regions, kelp is a low impact, nutritious, farmed food product:

[kelp can be] a nutritious food product with no arable land, no fresh water, no fertilizer, and no pesticides. And we’re helping clean the ocean while doing it

– nationalgeographic.com

 

… pollution from coastal salmon farms [was a problem in the past, but] these days even salmon farms are producing 10 to 15 times the fish they did in the 1980s and 1990s with a fraction of the pollution …

– nationalgeographic.com

 

Some farmed fish can be raised on vegetarian meal/feed

… some aquaculture species are raised on vegetarian feed [which can come in the form of meals and oils] (earthjournalism.net)

 

Sustainable fish feeds are on the rise. Fishmeal and fish oil used in feeds may come from trimmings from processing plants. Additionally, substituting plant proteins for fishmeal in feeds is also becoming more prevalent (aquaculturealliance.org)

 

Is a way to increase the food supply for the human population that doesn’t rely on sufficient wild animal population numbers 

Obviously fish farming is like land based animal and crop based agriculture – it relies on human induced breeding instead of wild animal population numbers 

The one asterisk to this is the feed type used. Obviously if wild caught fish are used as feed, this decreases the legitimacy of using farmed fish as a means of food production that doesn’t rely on wild caught fish to sustain

 

From aquaculturealliance.org:

Fish farming, when done sustainably, can be the answer to filling the gap in seafood supply that stressed fisheries are creating.

 

Aquaculture can be profitable as a business

[This can depend on key goals such as] maximizing growth rate and minimizing production costs (nature.com)

 

[It’s worth noting that catfish have been one of the most commonly farmed species in the US, and the industry has faced a number of economic problems in the past such as] plateaued product prices, increased production costs, international competition and economic recession. US market prices for catfish have remained relatively stable for the last twenty years (USDA 2010), while production costs, such as fuel, have steadily increased (nature.com)

 

The outlook for aquaculture looks favorable

Increasing human populations combined with limited natural resources in freshwater and the world’s oceans, which are currently near maximum harvest yields … mean that the demand for seafood must be met by aquaculture (nature.com)

 

This resource efficient protein can fill the gap in supply to meet the demand of the world’s growing population. The tools are now available to assist farms in developing sustainably, and it is up to farmers to take advantage of them (aquaculturealliance.org)

 

The world now produces more farmed fish than beef [and amounts] to nearly half of all fish and shellfish consumed on Earth

Aquaculture has expanded about 14-fold since 1980

Population growth, income growth, and seafood’s heart-healthy reputation are expected to drive up demand by 35 percent or more in just the next 20 years.

With the global catch of wild fish stagnant, experts say virtually all of that new seafood will have to be farmed

– nationalgeographic.com

 

Aquaculture shows potential to improve in the future terms of production and technological advances, as well as sustainability

[Potential to improve might come from] recirculating systems and aquaponic systems [which could help deliver] a fresher and more environmentally friendly product, with less fossil fuels and expense in transport, packaging and storage, as well as the appeal of a locally-grown product. … [and] … marine aquaculture, offshore areas offer great potential for culturing species due to a lack of space restrictions, good water quality, and the ability to culture species that are in great demand

[Furthermore] aquaculture production reduces pressures on natural stocks, and environmentally unsustainable methods of capture [and] Developing and developed nations will both benefit from an increased realization of the potential for aquaculture, as well as the need for protein derived from aquaculture in the face of continuing population growth

– nature.com

 

Conversion efficiency can be high compared to other types of meat

Farmed seafood is incredibly resource efficient, especially when compared with other animal proteins (beef, pork, chicken).

The feed conversion ratio, which is the measurement of how much feed it takes to produce the protein, is 1.1.

This means that essentially one pound of feed produces one pound of the protein.

Beef, pork and chicken’s feed conversion ratios vary between 2.2-10.

As a result, seafood’s protein retention, as well as energy retention are remarkably high as well.

– aquaculturealliance.org

 

The national geographic resource listed has a graphic showing the conversion efficiency of different meats

 

Read more about the sustainability of different meats in this guide

 

Might have a higher chance of being free of environmental contaminants

Farmed fish are generally free of environmental contaminants like mercury and heavy metals, as they exclusively eat human-processed feed. Fish feed’s toxin levels are regulated (aquaculturealliance.org)

 

In some cases, aquaculture can increase water quality

[Like for example where] filter-feeders, like shellfish [are farmed] (aquaculturealliance.org)

 

Can be used as a form of small business in lesser developed regions

[For example, some families can use small ponds to farm species like fresh water prawns] (nationalgeographic.com)

 

Fish waste can sometimes be used for crop fertilization

[There is an example in Bangladesh of fish waste being used to fertilizer rice crops] (nationalgeographic.com)

 

Cons Of Aquaculture & Fish Farming

There can be practical problems with pond based aquaculture

There can be some practical problems with pond based aquaculture such as deep green pond water, muddy pond water, a red layer on the pond water, oxygen depletion in water, excess ammonia, production of hydrogen sulphide, black mud at the bottom of a pond, large aquatic plants in ponds (researchgate.net)

 

Good management may not prevent technical difficulties with aquaculture

… even under good management, several technical difficulties may arise during fish culture with a possibility of large scale loss of production (researchgate.net)

 

Some farmed fish need wild fish as feed, and it can be resource inefficient when considering feed to production conversion

… [some farmed fish species, and] particularly more recently domesticated species like salmon, require wild fish rendered as fish meal and fish oil for their food. What this means is that most of the time, it takes more than a kilogram of wild fish to create a kilogram of farmed fish

… [one report indicated that the] feed-to-edible product ratio … could be more than 3 kilograms of forage fish to produce 1 kilogram of edible farmed fish

[Although, it should be noted that fish farming has become more feed conversion efficient in recent times]

– earthjournalism.net

 

[Of all the farmed organisms, fish might have the best feed conversion efficiency for several reasons to do with requiring less energy -] One of the appeals of aquaculture, both as a profitable business, and as a subsistence provider of protein for human populations, is in the efficient growth of fish … [and several key factors lead] to energy savings, which provides more available energy for growth, resulting in the highest feed conversion efficiency of widely domesticated animals

– nature.com

 

Farming carnivorous fish, such as salmon, does not always reduce pressure on wild fisheries

 Carnivorous farmed fish are usually fed fishmeal and fish oil extracted from wild forage fish.

– wikipedia.org

 

The resource footprint of aquaculture can vary

The typical resources required for aquaculture might involve feed (which carries it’s own footprint), water, power used on site, and processing and storage energy used (nature.com)

Energy can come from fossil fuels like coal (nationalgeographic.com)

There’s also effluent and waste management to consider from the farming process

Some data suggests that aquaculture is among some of the industries in the US that use the most water

 

Fish farming can use forage fish species, which can undermine marine food webs and have a secondary impact on other fish species in the wild

… the exploitation of the world’s forage fish is undermining marine food webs. Some 20 percent of the world catch is now forage fish, the vast majority of which is used for aquaculture feed (earthjournalism.net)

[earthjournalism.net has a good graphic where they show how top predator, intermediate predator, first order consumer and primary producer fish species all relate, and what impact consumers are really having when they eat a fish farmed with wild fish feed]

 

There’s potential waste and waste pollution to consider with fish farming

[Waste comes in the form of] fecal matter and unused feed [and] These largely nitrogen-based wastes can cause oxygen depletion in coastal environments and a net loss of marine productivity in certain coastal areas

Additionally, the use of antibiotics, antifoulants, and pesticides [can all cause waste pollution in the external environment]

 

From aquaculturealliance.org:

In the past, when the aquaculture industry was just getting its footing, certain factors inhibited the industry from producing fish sustainably [and] environmental problems did arise [such as] nutrient and effluent build-ups, the impact of fish farms on local wild fisheries with respect to disease and escaping, and environmental degradation due to the site’s location

 

Can result in disease, abandonment habitat destruction

[One example of this is when shrimp have been farmed in near coastal mangrove forests in the past. After disease set in, the ponds were abandoned, and the result was the destruction of] hundreds of thousands of acres of mangrove forests – ecosystems critical to the production of wild fish and the protection of the coast from storm surges (earthjournalism.net)

 

Disease transfer from farmed fish to wild fish is a potential problem

The farming of species in wild environments can be a vector for disease proliferation in the wild environment. Disease transfer in salmon aquaculture is perhaps the most reported instance of this phenomenon (earthjournalism.net)

 

Farmed fish escaping into the wild environment might be problematic

[The two issues with farmed fish escaping into both the ocean and land based fresh water sources, and that there’s risk the farmed fish dilute] wild populations’ genetics [and there’s also the chance that farmed fish with high reproduction rates take over a wild environment]

 

There can be a conflict of interest between production at scale, meeting demand, running at profit and the comfort of the fish

[In some instances, the only way to meet demand and run at a profit in some fish farm systems, is to pack fish into high densities, and there is question over how comfortable this is for the fish] (nationalgeographic.com)

 

Some slaughter methods are considered to be inhumane

[From an animal rights perspective, some slaughter methods can be considered inhumane, and some can be considered to be more humane] (wikipedia.org)

 

Sources

1. Hussan, Ajmal, Gon Choudhury, Tanmoy, T N, Vinay, Gupta, Sanjay, 2016/08/01, 6, 9, Common problems in aquaculture and their preventive measures, 2, Aquaculture Times, Available at https://www.researchgate.net/publication/312947314_Common_problems_in_aquaculture_and_their_preventive_measures

2. https://earthjournalism.net/resources/environmental-problems-of-aquaculture

3. Allen, P. J. & Steeby, J. A. (2011) Aquaculture: Challenges and Promise. Nature Education Knowledge 3(10):12, available at https://www.nature.com/scitable/knowledge/library/aquaculture-challenges-and-promise-23690921/

4. https://www.aquaculturealliance.org/blog/what-is-the-environmental-impact-of-aquaculture/

5. https://www.treehugger.com/aquaculture-problems-inherent-to-aquaculture-1301970

6. https://www.nationalgeographic.com/foodfeatures/aquaculture/

7. https://en.wikipedia.org/wiki/Fish_farming

Leave a Comment