All fish naturally produce waste into their habitats, and farmed salmon are no exception. We are conscious that the concentrations of fish in our farm mean we have to take extra care to ensure that local emissions are at safe and legal levels. These emissions are largely comprised of excess feed, faeces from fish and sometimes copper from the fish net. Fish waste is a natural part of the eco-system and provide nutrients which sustain the growth of plankton, which are eaten by larger species. However, too many nutrients in one area can potentially harm existing species through eutrophication.
Ensuring Long-Term Sustainability
The release of these emissions into the sea is strictly regulated and we always fulfil our legal obligations to protect the environment. We work with local authorities to investigate issues and improve our practices. After fish have been harvested, the area is left fallow for a period, much like land-based farmers who rest their fields. This fallow period lasts a minimum of six weeks in Shetland, although normally we keep the farms fallow for at least two to three months across whole management areas. We do this to allow time for the seabed to recover naturally over time. To ensure the long-term sustainability of our farms and the sea, we never operate if our impact is predicted to be irreversible. When we plan our sites, we take into consideration areas with good currents to disperse faeces and reduce concentration levels. Furthermore, we actively monitor the seabed under and around our farms to perform testing and report any problems. Grieg Seafood Shetland is investing in a state-of-the-art integrated operations centre to develop specialised feeding expertise and reduce instances of overfeeding. Although we are still using copper-based paints at some of our sites, we plan to return becoming to being 100% copper free in the near future.
Working Collaboratively to Improve Environmental Outcomes
In Shetland, half of our sites are deemed satisfactory according to regulators. We know we have more work to do and welcome the help of the Scottish Environment Protection Agency (SEPA) to improve. While there definitely is room to learn and improve our practices, we believe some of our unsatisfactorily rated sites have been rated based on inaccurate modelling projections. As a result, we hope to improve environmental modelling in collaboration with SEPA to get the most accurate ratings possible. As technology and methods improve, we continue to gain better understanding of our impact on the environment and how to mitigate any negative consequences.