Salmon farmers have long understood that rearing healthy fish requires a healthy environment and that, to successfully operate at the same locations year after year, farming practices must have no lasting impact on the marine ecosystem.
As such, environmental monitoring is established practice, with each farm operating to its Controlled Activities Regulations (CAR) licence regulated by SEPA (Scottish Environment Protection Agency). This sets limits on fish biomass and medicine use, informed by the marine environment’s capacity to breakdown and disperse materials, as well as any local sensitivities.
Among the many criteria farms are required to meet are two key biological standards relating to the seabed: one focused on its condition directly adjacent to the salmon pens; the other further afield at the edge of the allowable zone of effect.
To ensure compliance, farms are measured against these standards during peak production when fish biomass and, in turn, fish waste are approaching their maximum.
Over the last year however, Scottish Sea Farms has been repeating similar environmental monitoring once farms are fallow – free of fish – to help increase understanding of the ability of the seabed to regenerate.
Scottish Sea Farms Head of Sustainability and Development Anne Anderson said: ‘While farms already adhere to strict environmental regulations, which are monitored by routine checks and unannounced SEPA inspections, we wanted to go even further in our quest to demonstrate the sustainable nature of salmon farming.
‘Building on previous work at regional level, we have been analysing the benthic conditions of seabed sediment samples from fallowed sites around our farming estate.
‘The initial findings are promising, indicating, as we have long argued, the ability of the marine environment to regenerate.’
At Lismore North in Loch Linnhe, Argyll, where the company has farmed for over 30 years prior to fallowing the site in early 2019, recent sampling indicates that, in the three years since, significant recovery has taken place with faunal diversity now on par with before farming took place.
More recently, following a nine-month fallow period at Scottish Sea Farms’ Toyness site in Orkney, the range of animals and their abundance was found to have increased significantly.
‘The more post-fallow analysis we can do, be it several months or many years after a farm has been harvested, the more insights we will glean,’ said Anderson, ‘the aim being to increase wider understanding of just how regenerative salmon farming really is in relation to seabed restoration.’
Discussions are now underway with fellow salmon producers regarding rolling out this additional environmental monitoring sector-wide, with plans for the shared findings to be reviewed by a leading independent scientist.
‘Salmon farming has one of the lowest carbon footprints of all the animal protein producing sectors, it produces more edible meat per tonne of animal feed used, and here in Scotland and the wider UK we are one of the most valuable food exports,’ said Anderson.
‘Yet there remains a degree of caution about the sector, stemming from a lack of science and understanding.
‘With this new environmental monitoring programme, we hope to chip away at that.’
The need for more evidence in this area takes on heightened importance against a backdrop of Scottish Government proposals to designate at least 10 per cent of Scotland’s seas as Highly Protected Marine Areas (HPMAs), which would see several key commercial activities banned, including fishing and aquaculture.
‘The proposals fail to take into account the regenerative nature of salmon farming,’ said Anderson, ‘just as they fail to acknowledge that Scotland’s salmon farmers have been co-existing with Marine Protected Areas for many years already.
‘As with wild Atlantic salmon, our farmed salmon require high quality water if they are to live and thrive, therefore it’s in our own best interests as a sector to protect our marine environment.
‘We know it. It’s why we invest so much time, effort, and resource into minimising any impact from our activities, ensuring we’re able to successfully farm at locations year after year – in the case of our longest-established farm at Dunstaffnage, for as many as 36 years.
‘The priority now is demonstrating it to regulators and other key decision-makers.’
You can read more about the Scottish Government’s controversial HPMA proposals and what they would mean for Scotland’s remote communities in the June 2023 issue of The Source (p5) by clicking here.
Image: seabed survey undertaken by Roving Eye Enterprises for Scottish Sea Farms