New study to evaluate benthic impacts of salmon mariculture

A collaborative project to improve understanding of the effects of salmon farming on the seabed in high-energy waters is underway in Orkney. Currently, the impacts of fish waste and uneaten feed on the seabed are monitored using the DEPOMOD model, which is based largely on data gathered from sheltered, in-shore sea lochs. However, at more exposed sites, the benthic impacts can differ significantly from those reflected in the current model. “With better data about the benthic footprint at these sites, salmon producers like Cooke can improve environmental monitoring and compliance, and potentially increase production – both in terms of farming existing sites and developing new sites.”

October 12, 2017

A collaborative project to improve understanding of the effects of salmon farming on the seabed in high-energy waters is underway in Orkney.

The three-year project, which is being led by the Scottish Association for Marine Science (SAMS) in collaboration with Dalhousie University in Nova Scotia, Canada, will inform the environmental monitoring and management of more exposed sites along Scotland’s west coast and the Northern Isles. Funding for the project in the amount of £231,907 has been provided by Cooke Aquaculture Scotland and the Scottish Aquaculture Innovation Centre (SAIC).

Currently, the benthic impacts of salmon farming – the impact of fish waste or uneaten feed on the seabed – are monitored by industry regulator, the Scottish Environment Protection Agency (SEPA), using the DEPOMOD model developed by SAMS, which is based largely on data gathered from sheltered, in-shore sea lochs.

However, at more exposed sites such as those found off the coast of Orkney and Shetland, waste matter is dispersed more widely by strong tides, and the seabed is harder and rockier. The benthic impacts can differ significantly from those reflected in the current model.

“With better data about the benthic footprint at these sites, salmon producers like Cooke can improve environmental monitoring and compliance, and potentially increase production – both in terms of farming existing sites and developing new sites,” explained Chris Webb, Environment and Development Manager at Cooke Aquaculture.

The research team, led by SAMS, will field-sample and analyze data from up to three dispersive sites around Orkney over a complete production cycle. This data will then inform the development of the NewDEPOMOD model and its use in SEPA’s proposed Depositional Zone Regulation (DZR).

SAMS marine biogeochemist Dr Natalie Hicks said: “This project will ground truth the existing model (DEPOMOD), which has historically been used in more static environments, and will increase the accuracy in predicting benthic impacts in fish farms based on a model prediction.

“It is a great opportunity for scientists to work alongside industry partners to promote sustainability, good potential economic gains and confidence that the environmental effects are not detrimental.”

“With greater knowledge comes better regulation and better farming, and that’s what this project is all about,\" commented Heather Jones, CEO at SAIC. \"One of SAIC’s priorities is to unlock additional capacity for aquaculture development, and this project could do exactly that, by providing industry and regulators alike with the knowledge to manage and farm our seas ever more productively, and ever more sustainably.”