New case study: improving environmental impact modelling for salmon farming

To research and improve NewDEPOMOD software

As demand for Scottish salmon grows, balancing aquaculture expansion with environmental protection is essential. Regulators and farmers rely on NewDEPOMOD, a software tool used by SEPA to predict how organic waste settles and disperses on the seabed. This modelling helps assess environmental impacts and manage seabed conditions around fish farms.

NewDEPOMOD represents a major advance over its predecessor, offering improved accuracy and adaptability to modern farming practices.

This ‘ExPAND in2 the future’ project aimed to enhance NewDEPOMOD and ensure it meets the evolving needs of Scotland’s salmon sector. The project brought together developers, researchers, regulators, and industry partners to refine the model and strengthen collaboration. Valued at over £620k, the partners were Salmon Scotland, SAMS and the University of Dundee. It is a follow-on study from an earlier project, called ExPAND.

Key objectives included improving waste behaviour data, updating parameters for new pen designs, and enhancing software functionality. Key achievements:

• Waste behaviour research: lab experiments measured how matter settled and resuspended under realistic flow conditions. This data improves model accuracy for both sheltered and exposed sites.
• Erosion studies: tests identified the shear stress needed to resuspend waste from different seabed types, informing predictions of waste movement.
• Feed waste quantification: a review highlighted the importance of distinguishing types of waste to improve environmental and economic assessments.
• Adaptation for new pen designs: updates incorporated characteristics of modern net pens, ensuring the model remains relevant as farm technology evolves.
• Software enhancements: developers improved code efficiency, added new features, and began migrating the platform to Java for greater flexibility.
• Stakeholder engagement: regular workshops fostered collaboration between farmers, regulators, and scientists, creating a shared understanding of modelling and its role in sustainable aquaculture.

ExPAND2 strengthened industry capacity by creating a forum for ongoing dialogue and technical development. The project’s findings will help refine SEPA’s regulatory parameters and support evidence-based decision-making, ensuring salmon farming grows responsibly while protecting marine ecosystems.

By advancing environmental modelling and promoting collaboration, ExPAND2 sets the stage for more sustainable aquaculture practices in Scotland and beyond.

The full title of this project is ‘ExPAND in2 the future: realising the full capacity of the Scottish salmon industry’.

Read the case study