The science of sustainable seafood, explained

Yes, we Can Go On Farming Salmon

Response to The Huffington Post: “Can We Go On Farming Salmon?”

by Neil Auchterlonie

The blog article “Can We Go On Farming Salmon?” by Sue Cross in the Huffington Post, presents many inaccuracies about salmon farming. The article is similar to much of the misinformation that is often perpetrated across the internet by those who are fundamentally opposed to the concept of farming salmon or any other fish, and do not have an understanding of the processes that are adopted by the salmon farming industry in the 21st Century. The article is a response to a proposed large salmon farm in Scotland and the points presented relate to: effluent discharge from salmon farms; fish health, sea lice, and fish welfare (and the use of medicines); genetic “pollution” from salmon farm escapees; and the use of feed. The information provided is poorly researched and portrays a lack of understanding of the salmon farming sector in general, and in Scotland in particular.

Taking these points in order:

Effluent discharge

The excretion of waste products from farmed salmon in the form of ammonia and faeces has the potential to cause eutrophication in the aquatic environment through the addition of nitrogen and phosphorus. In reality, though, these impacts are managed through an understanding of the assimilative capacity of the receiving environment based on hydrodynamic models that are adopted by the regulator, in this instance the Scottish Environmental Protection Agency (SEPA). These models are based on scientific studies undertaken by Dr Chris Cromey at the Scottish Association for Marine Science (SAMS) and take into account the local hydrological conditions on an individual site, setting limits for the biomass that may be stocked, as other relevant data such as wind speed and direction. Data is provided by prospective salmon farmers which is then entered into these models ultimately producing limits for the biomass that may be stocked safely in individual locations. There are numerous studies on the effect of salmon farm effluent on local environment, including, for example, biodiversity and those impacts are taken into account during the licensing process. During the operational period those impacts are monitored. The whole process is based on science and is very far removed from the scene that has been presented.

Fish health, sea lice, and fish welfare

Effluent discharge models also relate to the use of medicines, and in particular for medicines that are used to treat stock for sea lice caused by the salmon louse Lepeophtheirus salmonis. Those models take into account the environmental risk to the local environment, and set limits for the use of veterinary medicines on salmon farms in order to manage the environmental impact. Veterinary medicines also need to undergo a strict and lengthy licencing procedure, which includes the provision of environmental toxicity data as well as efficacy data, in just the same manner that other veterinary medicines are licenced. The use of veterinary medicines is strictly controlled and are administered under the supervision of veterinary surgeons. Fish health is primarily addressed through legislation, of which the UK has a lengthy history dating back to one of the earliest pieces of fish disease legislation in the Fish Disease Act of 1937. The industry has been at the forefront of strategies such as Area Management Agreements that bring together different producers (and the wild fisheries sector) to share information about health status, veterinary treatments and the timing of production operations in a way that minimises the risk of disease transfer between farmed stocks, and between farmed stocks and wild fish. Fish welfare is also increasingly addressed through legislation and some of the welfare science now extends back more than a decade and has produced data on which codes of practice for the industry are based, for example the Code of Good Practice for Scottish Finfish Aquaculture. Again, the approach is one that is very much based on scientific evidence.

Genetic impact on indigenous stocks

Interactions with wild salmonids are of key importance to the salmon farming industry, and there is potential for the introgression of escapee farmed salmon with wild stocks. There are a number of ways the industry is addressing this risk, with the adoption of technical standards for farm equipment key in those to avoid the risk of equipment failure and stock loss. The risk does exist, though although the survival of escapee farmed salmon is generally considered to be low, and the loss of stock is proportionally very low compared with the number of salmon reared. In Scotland operators have a legal duty to report fish escapes which are published and provide data on the numbers and locations on an annual basis. There are reports of introgression in a very few stocks in Ireland and Norway, although the data are still very limited especially considering that the industry has been active since the late 1960s. Clearly, the industry will continue to manage the risk as far as it is able, not wishing to lose valuable stock within the farming process.

Fishmeal and feed

The information presented on fishmeal production completely misses the point that the (fishmeal) industry is highly regulated, heavily engaged with sustainability agenda, and is a sector where annual volumes of certification of the product is at a high level relative to other feed ingredients. The global annual production is relatively stable at approximately 5 million tonnes of fishmeal and 1 million tonnes of fish oil, outside of years where El Nino events occur in the South Pacific. The industry is engaged with the fish farming sector and NGOs to raise standards and communicate to consumers which are the better choices available.

Fishmeal and fish oil are vital feed ingredients used in the production of pig, poultry and fish. They are therefore central to the production of protein across the world, and global food security with its implications for humanity in the 21st Century. The small pelagic fish species used for fishmeal and fish oil production typically do not have direct human consumption markets, and the harvesting of these fisheries supports the economies of coastal communities in countries across the world. Because the fisheries are pelagic, any impact of fishing operations on marine habitat is negligible, and bycatch is often very low. Often the fisheries operate through stock management approaches based on scientific data and modelling, including the setting of annual or seasonal quotas. As well as whole fish used in the production of fishmeal and fish oil, byproducts from the seafood processing sector are also used, and IFFO estimates that approximately 35% of fishmeal and fish oil is produced from this raw material currently.

The reference in the text to a shortage of anchovies and the implication that this is a direct result of the growth of aquaculture is a completely false statement. Aquaculture is a growing industry, and that growth is essential to meet the protein requirements of a growing human population. The volume of fish oil produced annually is finite. Aquaculture growth has been facilitated through a reduction in the feed content of fish oil.

The Peruvian anchovy is the most important of anchovy species for the production of fishmeal and fish oil globally. Stocks of Peruvian anchovy fluctuate according to environmental conditions and these are taken into account in the stock management process undertaken by the Peruvian government. El Nino events, in particular, can affect stock, and it appears that environmental conditions may have more impact on stock populations than the level of fishing effort.

If you need any further information on responsible sourcing of marine ingredients, please see the IFFO website at: www.iffo.net.


In fact, most, if not all, of the points raised have been addressed by Scottish Government through the Ministerial Group for Sustainable Aquaculture, out of which has been produced an Aquaculture Science and Research Strategy in 2014, indicating that further research investment will continue on these subjects. That, in itself is a good indication that the industry will continue to use scientific evidence as the basis for progress on sustainability goals, rather than the misinformed speculation that has become the mainstay of many of the industry’s critics.

A Salmon farm in Scotland. Photo by Richard Dorrell
Neil Auchterlonie is the technical director of IFFO, The Marine Ingredients Organization. He has worked in the Scottish salmon farming sector, other aquaculture systems, as well as for UK government for many years.

Share this story:


Subscribe to our newsletter:

Read more:

Leave a Reply

Ray Hilborn's every-so-often newsletter

The best way to keep up with our stories.