Photo: Aquaculture

An Atlantic salmon farm. (Credit:axiepics via Flickr.)

Aquaculture is the fresh or salt water farming of any fish, shellfish, or aquatic plant. Aquaculture has been practiced for thousands of years, especially in places like China where it has provided a solid supply of protein for people.

Aquaculture is a relatively new industry in the western world as it's only been in the last 30-40 years that it has become a major industry. Since the 1970's, global aquaculture production has been growing rapidly at a rate of about 9% per year. Today, aquaculture produces at least 50% of the world's seafood and will likely continue to grow its production into the forseeable future as the demand for fish protein increases and the ability of wild fish stocks to meet the demand continues to dwindle due to overfishing and insufficient regulation. In fact, aquaculture is now the fastest growing form of food production on the planet.

Aquaculture is often called the "Blue Revolution" and carries the mantra that if you farm fish instead of catching them then you will relieve the pressure on wild stocks. This is the natural progression in food production and follows the terrestrial model where humans stopped hunting animals and started farming them in order to create a reliable food supply. However, there are limitations to the ideals of the "Blue Revolution" because pressure on wild fish stocks is only relieved if the same people that are catching the fish start farming them instead and if the fish that you are producing don't require more wild fish to produce (i.e. salmon farming requires more wild fish inputs than it produces as farmed product).

Environmental Impacts

Like any form of industrial production, aquaculture has environmental impacts. The major impacts for the aquaculture industry include: using more fish than they produce, disease and parasite transfer, the introduction and spread of exotic species, chemical pollution, habitat destruction for farm siting or due to farm activities, and the killing of predators that prey on the farmed species. For aquaculture, impact is dictated by three main factors which include:

1) Species in production
The higher the trophic level or food web position of the species being cultured the more inputs of feed will be required and thus more waste outputs will be released.

2) Location of production
The more ecologically sensitive the location of the farm such as mangroves, coastal estuaries, salmon migration routes, etc. the more likely there will be an impact on the environment due to farm outputs such as waste, amplified disease or parasites, escapes of cultured stock, or killing of predators.

3) System of production.
The more open the production system (e.g. open net pens) the more likely it is to have an impact on the environment. For example, open net pens are completely open and in anything that happens in the farm can be transferred to outside of the farm whereas closed containment systems contain all inputs and outputs.

To illustrate this with some examples, an example of an aquaculture system that has a high impact is salmon farming. It farms a high trophic level species in open net pens that are located on wild salmon migrations in BC's coastal ecosystems.

An example, of an aquaculture system that has a low environmental impact is shellfish, which is a species that is very low on the food chain and requires almost no inputs, is produce is sensitive but dynamic environments (intertidal zone), and is produced without much infrastructure.

Social Impacts

Social impacts are also considered to be a major impact of aquaculture production and there are numerous conflicts around the world. The major conflicts include: traditional livelihood and community displacement and abusive labor practices. In some cases in the impacts have been extreme and people have ended up being killed in the conflicts. Social impacts are mainly driven by export driven commodity production like shrimp, where companies seek to maximize profits by exploiting poor countries who have poor regulations.

What is the David Suzuki Foundation doing on aquaculture?

The David Suzuki Foundation (DSF) works on aquaculture issues both locally and internationally. Our local work involves efforts to mitigate the impacts of the salmon farming industry in British Columbia using science, improved management and promotion of closed containment technologies. The industry has a long history of poor practice, which is exacerbated by poor government regulation and inappropriate promotion of the salmon aquaculture industry, and there is a growing body of scientific evidence demonstrating their impact on wild salmon.

The Foundation is a member of the Coastal Alliance for Aquaculture Reform, which is composed of five B.C.-based groups that are working together to reform the salmon aquaculture industry in this province. Learn more about why you should think twice before eating open net-cage farmed salmon.

DSF staff also work within international forums to develop sustainability standards for the salmon aquaculture industry via the Salmon Aquaculture Dialogue. Internationally, our work has mainly involved participating in the Aquaculture Dialogues for shrimp, Pangasius (Asia catfish), Tilapia, and Bivalves. All of these species are consumed by Canadian consumers and produced overseas. DSF believes that Canadians should be responsible not only for the food we produce, but also the food we consume.