Fish farm environmental impacts

All farms must meet strict guidelines to ensure that the environmental impacts are assessed and managed safely.


Scotland has a robust legislative and regulatory framework in place which provides the right balance between growing the fish farming sector and protecting the pristine environment on which the sector depends. All farms must meet strict guidelines to ensure that the environmental impacts are assessed and managed safely.

Environmental Impact Assessment (EIA)

Environmental Impact Assessment (EIA) is a systematic means of assessing the likely significant environmental effects arising from a proposed development.

Finfish farms are listed in Schedule 2 to the 2017 EIA Regulations meaning that they will require an EIA if they are likely to have a significant effect on the environment perhaps due to their size, nature or location. Most finfish developments will require to be screened as to whether an EIA is necessary and, if the Local Authority determines that one is required, it must be submitted alongside the planning application. Shellfish farms are not subject to EIA but Local Authorities will still consider the potential environmental consequences of the proposal prior to granting planning permission.

Where a farm (either finfish or shellfish) is granted planning permission, the Local Authority may impose conditions on the development to manage its effects on the environment. Further information on EIA can be found on the Development Management pages.

Habitats Regulations Appraisal

Where an authority concludes that a proposed development is likely to have a significant effect on a Natura site, it must undertake an appropriate assessment of the implications for the conservation interests for which the area has been designated.

SNH advises competent authorities about potential damage to Natura sites.


Waste from fish farms (such as faeces and chemicals) can collect on the seabed under fish cages. Before operators can make discharges of any kind (including medicines) they must apply for and obtain a Water Environment (Controlled Activities) (Scotland) Regulations 2011 (CAR) licence from SEPA. SEPA is primarily concerned with the environmental effect of discharges of effluent, waste and pollutants from the farm and will consider the extent and intensity of the potential damage arising from these releases.

New DEPOMOD is a Scottish Government funded computer model, recently upgraded by the Scottish Association of Marine Science (SAMS).  It predicts the impact of marine cage fish farming on the seabed, looking at the benthic impacts on sediment dwelling animals from marine cage farms given farm (configuration, feeding rate) and environmental information (bathymetry, water currents). It was launched in June 2017 and is currently being trialled by the fish farming industry.


Scotland’s aquaculture stocks are internationally recognised as having a high health status. All fish farming businesses are authorised by Marine Scotland under the Aquatic Animal Health (Scotland) Regulations 2009. MS Fish Health Inspectorate carries out assessments for disease control, sea lice management and containment measures.

Interactions with Wild Fish

Growing a sustainable salmon aquaculture sector and the conservation of wild Scottish salmon and associated fisheries are important objectives for the Scottish Government. Salmon aquaculture can result in elevated numbers of sea lice in open water and hence is likely to increase the infestation potential on wild salmonids. This in turn could have an adverse effect on populations of wild salmonids in some circumstances. The magnitude of any such impact in relation to overall mortality levels is not known for Scotland. Marine Scotland Science is undertaking research in this area and more information on aquaculture interactions can be found on the research webpages.

Industry Codes

In addition to regulatory regimes, both the finfish and shellfish industries have developed codes of good practice to ensure adherence to industry standards.

Monitoring of Fish Farms

After a fish farm is consented its effects will continue to be monitored by a number of bodies, and many monitoring and survey reports are available online:

  • Scotland’s Aquaculture Website brings together regulatory data collected by SEPA, Marine Scotland, Food Standards Scotland and the Crown Estate including site details, survey results and escape incidents

  • Marine Scotland’s Fish Health Inspectorate publishes information relating to its inspection and operational activities on its web pages on a regular basis

  • SEPA publishes details of compliance with licences issued under CAR as part of its compliance assessment scheme

  • The SSPO publishes quarterly and annual Fish Health Management reports

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