In Scotland, any business or organisation whose activities could impact on the water system is subject to the Water Environment (Controlled Activities)(Scotland) Regulations; more commonly known as the Controlled Activity Regulations (CAR).

Under CAR, the Scottish Environmental Protection Agency (SEPA) will assess the likely risk posed by the activities before deciding if they are to be permitted and, if so, at what level.

In terms of how and where it applies to salmon farming, CAR regulates our activities in freshwater, seawater and processing.


Freshwater facilities

Loch Creran

We have two freshwater facilities: our main Barcaldine Hatchery near Oban, which is equipped with a recirculating aquaculture system, and our more traditional flow-through Knock Hatchery on the Isle of Mull.

Both facilities rely on sourcing freshwater from a nearby reservoir, river or loch then discharging used water into a nearby sea loch.

Key to both processes is that the good quality water classification of the local water body is protected.

As such, all water drawn is done so in accordance with what’s known as a water abstraction licence. Issued by SEPA, this sets maximum daily flow volumes to protect the source water body.

Similar care is taken with regards to discharging water back into local water bodies, with all our hatchery water treated to remove any nitrogen, phosphorous or carbon.


Marine farms

Lerwick, Shetland. Photo courtesy of Billy Arthur

Out on a marine farm there are five key factors that determine impact on the local benthic (seabed) biology and chemistry:

  • Fish feed used which can release nitrogen and phosphorus
  • Organic waste (fish faeces) produced
  • Veterinary medicines administered: bath treatments and in-feed
  • Anti-foulants used to prevent marine build-up on netting
  • Local marine conditions – in particular, seabed sedimentation types, current speed and water depth – and their ability to breakdown, disperse and assimilate the residues of the above.

Information on each factor is input into scientific modelling and used by SEPA to advise on what the local marine environment can sustain.

If SEPA decides that local marine conditions can sustain a salmon farm, it will then award that farm its own CAR licence which sets farm-specific limits on the maximum weight of fish (biomass) that may be stocked at any one time, as well as any veterinary medicines that may be used.


Managing our benthic impact

Scalloway, Shetland. Photo courtesy of Billy Arthur

We have a number of measures in place to help minimise our impact on the seabed, from good animal husbandry practices to the latest advances.

These measures include but are no means limited to:

  • Investing in a new hatchery with recirculating aquaculture system (RAS) – enabling us to produce bigger smolts, reduce the time these fish spend at sea by up to two months and create the opportunity for longer fallow periods
  • Stocking sea pens in low densities of no more than 1.5% fish to 98.5% water– in environmental terms, less fish in each pen means less fish feed and faeces, making it more manageable for the local marine environment to disperse and sustain
  • Regularly monitoring pen-specific levels – checking everything from oxygen levels to sediment quality underneath and around farms
  • Deploying fallow periods – giving the local marine environment three months or more without fish or nets
  • Minimising wasted feed – by investing in high-tech feeding systems at 42 out of 42 farms, we are able to observe feeding behaviour via underwater cameras and can start, stop and adjust feeding according to fish appetite. Our approach to feed is very much led by the fish response, significantly reducing the likelihood of wasted feed
  • Reducing our feed conversion ratio – by investing in high-energy diets at all stages of the growing cycle. Not only has this helped reduce the volume of fish faeces produced, but because the fish absorb and convert more of the feed into their growth, the faeces that is produced contains fewer nutrients meaning less are discharged into the marine environment
  • Adopting vaccines and non-medicinal approaches to fish health – helping us reduce the quantity of veterinary medicines used, whilst still protecting the welfare of our stocks
  • Reducing copper usage – clean nets are critical for fish welfare and good water exchange. Our new HDPE netting has a stronger frame that can withstand regular cleaning in-situ. This removes the need for copper-based anti-foulant (commonly used by boat, ship and other marine operators to protect against the build-up of marine growth) and helps to preserve the natural balance of the surrounding environment.

Marine protected areas (MPAs)

Scotland’s west coast and islands are home to several marine protected areas (MPAs); areas where important habitats and species are thriving, and where protected status has been awarded to help ensure they continue to thrive.

This protection may include restrictions on activities such as sailing, mooring, fishing, development of the area or the removal or disruption of marine life.

Almost all of Scotland’s MPAs were given their designated status long after the growth of salmon farming, proving that salmon farms and marine life can happily co-exist.

One of the most recent examples of this is the Harbour Porpoise Special Area of Conservation which was created on 22 September 2016. The largest protected area in Europe for this species, thought to cover over 5,000 porpoises, it spans 13,800km2 of the Inner Hebrides and Minches – an area with a high number of established salmon farms.

It’s further proof that, with responsible farm management and good fish husbandry, salmon farming and species of special interest can co-exist happily in the same waters.

Wildlife sightings app

Photo courtesy of Martyn Lennie

Testament to the abundance of wildlife and marine life spotted around our farms, 2021 saw us successfully pilot and roll-out a new wildlife sightings app.

The app enables our farm teams to record sightings – from orcas and otters to sea gulls and sea eagles – via their phone or laptop, acquiring coordinates accurately from GPS signals and providing a consistent picture across all our farms.

The data collated is shared with the Biological Record Centre, which is a component of the National Biodiversity Network, meaning that it can be used by everyone from the general public,  conservationists and NGOs to the wider science community.

Sourcing cleaner fish responsibly

Lumpsucker, a species of cleaner fish

Our commitment to safeguarding Scotland’s waters extends beyond our own farm settings. We’re also working to ensure that the cleaner fish we use are sourced in a responsible way.

All lumpsuckers that we use are now from farmed origin. Using eggs from wild-caught broodstock (parent fish) they are raised in hatcheries; a process that takes roughly one year.

In contrast, ballan wrasse – the second key species of cleaner fish that we use – take considerably longer to raise in hatcheries with females reaching sexual maturity at six years, longer for males, with offspring taking 18 months to reach the correct size for deployment in sea pens.

As such, the majority of ballan wrasse that we use are still wild-caught. In the interests of fish welfare and the environment, this is done in accordance with mandatory measures, implemented by the Scottish Government following successful piloting of voluntary measures set out by the sector itself in partnership with Marine Scotland and RSPCA Assured.

These mandatory measures ensure that:

  • Ballan wrasse can only be fished for during set periods of the year that avoid breeding season
  • Only ballan wrasse of a specific size are caught, aided by the use of specially modified pots – larger fish of reproductive age can’t get in, nor can other marine animals, while younger smaller fish can swim out
  • All fishermen supplying to the sector are approved and sign-up to the mandatory measures above
  • The ballan wrasse that are caught are health-checked, measured and stored in seawater tanks ahead of transfer to farm – all of which is in accordance with RSPCA Assured welfare standards
  • Details of all wild wrasse caught are recorded and reported to Marine Scotland.

This data tells us that wild wrasse are thriving, providing the clearest indication that they are being fished sustainably.

You can read more about the mandatory measures in place here.


Banner photo: Scalloway, Shetland, courtesy of Billy Arthur