top of page

Aquaculture’s real revolution is on land

The same kind of enthusiasm and optimism expressed in a recent commentary by the executive director of the Newfoundland Aquaculture Industry Association for the promise of industrial aquaculture to feed the hungry of the world was heard decades earlier during the Green Revolution in agriculture.

Prompted by a series of famines in the 1940s and concerns about a growing world population, the Green Revolution began putting to use new and emerging science and technology to develop high-yielding cereal grains, genetically modify crops, produce synthetic fertilizers, build massive irrigation infrastructure and manufacture an arsenal of pesticides and herbicides.

It has been said that the Green Revolution “super-charged” our ability to produce food. It also displaced small-scale mixed farms and replaced them with large-scale mono-culture operations owned by vertically-integrated corporations. There has been a decline in agricultural biodiversity where only a few varieties of high-yielding crops are now grown world-wide. This type of agriculture required a massive increase in the use of synthetic fertilizers which have polluted coastal and freshwater ecosystems. Farmlands have been turned into deserts and insects and diseases have developed resistance to pesticides and antibiotics.

Similar issues now plague industrial aquaculture.

Open net pen fish farms operate like industrial feedlots in coastal waters. They generate large quantities of wastes (200 mt for every 1000 mt of production) and the cost of waste disposal is paid by the environment, not the industry. All the science and technology being pressed into the service of expanding industrial salmon feedlots have not succeeded in keeping fish or the environment healthy. It has failed to prevent the desertification of sea bottoms, eliminate the release of chemical pollutants, prevent interactions between farmed and wild salmon populations and prevent the outbreak and spread of pests and diseases.

Like industrial agriculture, the fish farming industry has enlisted the power of science and technology to make improvements in their operations. Most of their effort has been directed to improving production and efficiency. Automated feeding has reduced the number of workers needed to operate a single farm. Underwater cameras have helped to improved feed efficiency.And, a genetically modified salmon that will grow faster has been developed but not approved for commercial production.

The hungry of the world are not eating Canadian farmed salmon, mussels or oysters. Those products are feeding us tubby and over-fed North Americans and Europeans. I can’t think of an instance when an emergency shipment of farmed salmon was sent to Somalia or Ethiopia to feed the starving.

Farmed fish represents a very small portion (6 per cent) of per capita global protein consumption. According to the most recent data from the UN Food and Agriculture Organization, plants and animals still represent about 80 per cent of the primary source of protein for most of the world’s population. Globally aquaculture is dominated (89.1 per cent) by seaweeds, crustaceans and freshwater fish production which is land-based. Open net pen farmed salmon represents only 2.8 per cent of global aquaculture production.

As for addressing the environmental impacts of open net pen fish farms, changes to the composition of feed pellets have reduced (not eliminated) the use of wild fish and the development of vaccines has reduced (not eliminated) the use of antibiotics. In some jurisdictions, management practices similar to those used in intensive agriculture such as fallowing and a form of crop-rotation referred to as bay management have been introduced.

Any benefits gained from these improvements have been offset by an increase in farm sites and the number of fish produced per feedlot. Feedlots which once raised 100,000 now raise 300,000 to 700,000 fish and where there were once three or four feedlots, there are now 20. Fallowing and bay management have failed to stop disease and sea lice epidemics or to prevent many salmon farms from routinely requiring some kind of remediation because the sea bottom under their net pens has become so toxic that 60-70% of biological diversity has been lost. A more recent proposal to manage fish farm waste is integrated multi-trophic aquaculture (IMTA), the process of growing shellfish and seaweeds next to salmon farm to gobble up the excess nutrient and organic wastes. To date, all scientific studies have failed to demonstrate IMTA’s effectiveness.

In Canada, traditional fisheries still economically and socially out-perform the aquaculture industry. In 2010 Canada’s exports of wild capture fish and seafood products were worth more than $3.4 billion, three times the value of aquaculture exports. Lobster exports exceed aquaculture export. In Atlantic Canada, for every job in aquaculture there are at least 10 jobs in the traditional fisheries.

Fish farming does have a place in the economic mix of communities but it is on land where, as with other industrial operations, the real and total cost of production is paid by the industry and not the environment and traditional fisheries.

Inka Milewski is a marine biologist and former science advisor with the Conservation Council of New Brunswick.

0 views0 comments

Recent Posts

See All


bottom of page