Fish farming: how does it affect the environment?

Dead fish are seen at the Rodrigo de Freitas lagoon in Rio de Janeiro, March 13, 2013. Thousands of fish have been removed from the lagoon after oxygen levels dropped due to pollution, according to local media. Rodrigo de Freitas lagoon will host the rowing competitions in the 2016 Olympic Games. REUTERS/Sergio Moraes (BRAZIL - Tags: ANIMALS SOCIETY ENVIRONMENT TPX IMAGES OF THE DAY) - RTR3EY19
Fish farms

Fish farms

Do you know where the fish you eat comes from?

It is viewed that eating fish is more ecological than eating meat;

however this can be seriously questioned as we learn about Aquaculture practices.

What is Aquaculture?

Just as Agriculture is the domestication of land (plants and animals), Aquaculture is the domestication of the ocean.

Why are we fish farming?

Our consumption of fish have outstripped the natural capacity of freshwater and marine fisheries. These can no longer provide enough supply. Fisheries are now considered to be fully or over-exploited (1). Therefore, Aquaculture provides an increasing proportion of fish supply and this will continue to rise.

How does it impact on the environment?

Intensive Aquaculture operations are held near freshwater streams, in the sea or on the coast. These practices are chemically and genetically destructive (2).





1. Fish faeces & feed: production of sediments.

2. Ammonium excretion

  1. Particles settle downstream producing a muddy deoxygentated substrate (5)(6)

2. Ammonia=toxic and uses oxygen during oxidation to nitrate-> oxygen depletion

Oxygen depletion

Aquaculture uses on average, more than one tonne of O2 to produce one tonne of fish (6).

Harms organisms around the fish farms, leading to destruction of ecosystems.

Genetic pollution

Domesticated fish adapt to captivity (making ‘weak’ genes, or non-adapted to the wild), as many escapes occur, these fish mate with the wild ones, risking of spreading their ‘weak’ genes (3).

Causes further stress on fragile species and increases their risk of extinction

Antibiotic resistance

Intensive farming means increase risk of diseases. To treat these, fishes are given antibiotics (6).

Release of antibiotics into the environment-> harms sensitive species + increases the rate of evolution of resistant bacteria (6).


The risk of diseases increases in fish farms, infestation of diseases put at risk nearby species at risk of also being infected (4).

Harms sensitive species

Considering all the pollutants the ocean contains, is eating fish healthy?

A study looking at the concentration of organochlorine contaminants in salmons found that these were higher in farmed salmon than in the wild ones. Furthermore, it was found that European-raised salmon had significantly greater contaminant loads than fish farmed in North and South America.

The conclusion made by this study was that the consumption of farmed Atlantic salmon may pose health risks that outweigh the beneficial effect of fish consumption (7).  


Intensive Aquaculture is very harmful to the environment and in addition fish accumulates many contaminants that are present in the sea. Therefore it is questionable whether consuming it is worth its beneficial effect.

Decreasing fish consumption and favoring organic farmed fish which is less intensive and does not use antibiotics is an ethical option, or you can check out our recipes and guidebooks and get inspired to live a plant-based diet!

You are informed, you, as a consumer, guide the direction the big industries take.

Consume better and less that is the mantra!


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(1)FAO 2009. 139th Meeting of the AFS-Sustainable Global Fisheries-Sustainable Fisheries: the Importance of the Bigger Picture. Nashville, Tennessee (USA).

(2) Marra (2005).When will we tame the ocean. Nature436:175-176

(3)Vasemagi (2005). Extensive immigration from compensatory hatchery releases into wild Atlantic salmon population in the Baltic sea: spatio-temporal analysis over 18 years, Heredity95: 76–83.

(4) Rosenberg (2008).The price of lice. Nature 451:23-24

(5) Braithwaite (2010).Aquaculture and restocking: implications for conservation and welfare. Animal welfare19:139-149.

(6) Warner (1993). Fish farming and the environment. Journal of Experimental Marine Biology and Ecology109:39–51.

(7) Hites (2004). Global Assessment of Organic contaminants in farmed Salmon. Science 9:226-9.

Caroline Balloux

Viola Brugnatelli is a Neuroscientist specialised in Cannabinoid circuitry & GPCRs signalling. Her academy and research training let her gain extensive experience on medical cannabis and terpenes both from preclinical as well as clinical perspective. In her vision, collective human knowledge behold the power for overall improvement of life, thus, it should be accessible and shareable. Viola is Founder of the science online magazine Nature Going Smart, and works as a consultant for companies & individual patients, as a speaker at seminars and workshops and as a lecturer in a CME course on Medical Cannabis in Italy, at the University of Padua.

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