Atlantic salmon

Feed used in salmon aquaculture is traceable and requirements are in place for responsible ingredient sourcing, including the use of certified ingredients. However, salmon is a net consumer of fish protein. The production of Scottish salmon relies on a variety of different feeds, including specialist formulation. Historically, the most important ingredients in salmon feed have been fishmeal and fish oil, which provide an almost optimal complete feed in a convenient and highly digestible product form. The primary fisheries supplying fishmeal and fish oil are found globally (Ireland, Denmark, Iceland, South Africa, Norway, Peru, USA) and have a range of species (anchoveta, blue whiting, capelin, menhaden, Norway pout, sand eel, sprat). Due to a need to reduce costs and secure the protein supply, cheaper alternative ingredients (for example soybean and rapeseed oil) have been progressively substituted in commercial feed formulas. In Scotland, novel feed ingredients are also being used, such as insect meals and algal oils.  Three main feed manufacturers are dominant in Scotland, these are Biomar, Cargill and MOWI. These feed companies have policies in place to ensure that the protein and oil component of all main feeds used in Scotland is traceable and responsibly sourced, and this can be independently verified. The dependency of fishmeal and fish oil (known as the Feed Fish Dependency Ratio) for Atlantic salmon currently indicates that more fish protein is required in the diet than these fish produce, making them a net consumer of fish rather than a fish producer. Most of the soy and/or palm oil used by the main feed companies is also responsibly sourced.

Salmon farming in marine open net pens has a negative impact on the environment.Habitat alteration is small scale through the use of mooring grids only and does not impact ecosystem functionality. All juveniles used in salmon aquaculture in Scotland come from hatcheries, however, wild caught cleaner fish are used. Both lumpfish and wrasse are used as cleaner fish but the stock status of both species are unknown and available data is minimal.Salmon farms in Scotland rely on chemical usage. Fish farms use a range of medicines and products containing chemicals, such as disinfectants and antifoulants to ensure the health and welfare of the fish they grow and to maintain and protect the farm infrastructure and equipment (e.g. pens and boats). The medicines and products used on fish farms are approved and regulated by the Health and Safety Executive and Veterinary Medicinies Directorate and SEPA regulate discharges in order to protect the environment. However, these regulations are not thought to be fully effective as 50% of benthic surveys carried out in 2020 were deemed to be unsatisfactory. Discharges of waste from salmon farms also have a measurable negative effect but this is within a defined allowable zone of effect which is equivalent to the 100 metre based limit applied to all other discharges to the marine environment.There is a problem with both parasites and pathogens in salmon aquaculture. The Scottish Government recognise that salmon farms increase the number of salmon sea lice (Lepeophtheirus salmonis) in the environment and that this may have an impact on wild salmon. The consequences of increased sea lice levels on wild populations of fish are unclear and quantifying wild salmon population mortality due to sea lice infections is complex, and the magnitude of lice depends on environmental, biological and ecological variables. Currently, there is a lack of information on the impact of sea lice from aquaculture on wild salmon in Scotland, however, in 2018, Marine Scotland started a ten year programme of research to investigate any potential risk to wild salmon from sea lice in the Scottish coastal environment. Pathogenic disease outbreaks do also occur but are not thought to threaten regional level operations. It has been found that pathogens can impact wild species and may result in mortality but this is not thought to be found at a population level.There is a risk of escapes of farmed salmon with evidence of negative ecological effects. Open net pens used in salmon farming are vulnerable to escapes and large numbers have escaped in the last 10 years. An example of this is at the beginning of 2020, 74,000 salmon escaped from a farm on a site off the island of Colonsay. Escaped farmed salmon can alter the natural environment by indirectly affecting aspects of the wild population behaviour, predators and disease interaction. From March 2021, salmon predators are no longer lethally controlled in Scotland. d.

There are practices in place to ensure animal welfare and humane slaughter.Around 70% of Scottish salmon are certified to the RSPCA Farm Assured scheme and remaining salmon are thought to be reared to the same welfare standard. The RSPCA standard for farmed salmon takes into account UK legislation, official codes of practice, scientific research, recommendations of the Farm Animal Welfare Committee (FAWC) and the practical experience of the aquaculture industry.There are two methods of stunning used in Scotland, percussive and electric. Both methods are humane and are designed to minimise stress on the fish. This process is carried out by trained personnel and is independently audited.

This assessment scores well for management measures but would benefit from third party certification.Scottish salmon are farmed to the Code of Good Practice, which is voluntary. It is believed that the large majority of farms in Scotland are signatories to the Code however compliance cannot be confirmed.Aquaculture policy in the UK is a devolved matter, with the separate administrations of Wales, England, Northern Ireland, and Scotland responsible for its collective oversight. Aquaculture production in Scotland is covered in the 2015 National Marine Plan. This plan covers the management of both Scottish inshore waters (out to 12 nautical miles). Scotland’s River Basin Management Plan (RBMP) also sets out a range of actions to address water quality, physical condition, water flows and levels, the migration of wild fish and invasive non native species. The RBMP is produced every six years by SEPA on behalf of the Scottish Government.In the UK, there is regulatory framework in place to address the environmental impacts of aquaculture. This includes the Habitats Directive 92/43/EEC and the Birds Directive 2009/147/EC, which form the cornerstones of the EU s nature conservation policy and protect valuable habitats and species. There is also regulation in place to cover the use of land and water resources, discharges including effluents and their impacts, biosecurity and disease management, However, these regulations are not always effective. For example, the regulations of the use of chemicals has found to be ineffective as they have been found to be negatively impacting the environment. There are also still large escape events occurring despite guidance regarding escapes in the Code of Good Practice.