Home > News & Events > New case study: georeferenced 3D photogrammetry - a tool for monitoring finfish aquaculture impacts on hard seabeds (SIF feasibility study)

New case study: georeferenced 3D photogrammetry - a tool for monitoring finfish aquaculture impacts on hard seabeds (SIF feasibility study)

A potential step-change in how hard seabeds may be surveyed reliably.

Monitoring the environmental impact of finfish farms on hard seabeds is challenging. Current survey methods rely on visual inspections using drop-down or towed cameras along gridlines, but these approaches risk missing key details and can have positional inaccuracies. Most georeferencing depends on the surface vessel’s GPS, which can introduce errors of over a metre due to currents and cable angles.

Valued over £90k, this feasibility study was led by Tritonia Scientific Ltd., with support from a steering group that comprised SEPA, NatureScot and Salmon Scotland. Funding came from the UK Seafood Innovation Fund (SIF feasibility study) and was supported by SAIC

The project explored the use of 3D photogrammetry - a technique that creates detailed, measurable 3D models from standard underwater imagery - to improve accuracy and efficiency. These models provide permanent, high-resolution records of seabed conditions, enabling repeated analysis, automated comparisons, and precise measurement of biological features.

The goal was to demonstrate that observation-class remotely operated vehicles (ROVs) could produce photogrammetric models comparable to diver-based surveys, while improving geolocation accuracy.

Key innovations and results:

  • Enhanced positioning: integrating Real-Time Kinematic (RTK) GPS into ROV navigation reduced positional error from up to 1.5 metres to less than 0.3 metres. Doppler Velocity Log (DVL) technology further improved underwater tracking.
  • High-quality models: ROV-generated 3D models of seabed areas matched diver-based models, with error distributions averaging less than 2 cm. Biological species counts, e.g., sea urchins, starfish, scallops, showed 100% agreement between methods.
  • Repeatable accuracy: replicated surveys demonstrated consistent precision, confirming the reliability of ROV-based photogrammetry for long-term monitoring.
  • Regulatory potential: combining photogrammetry with advanced georeferencing offers a robust, standardised method for detecting and measuring environmental changes over time.

The study confirmed feasibility and identified areas for improvement, such as optimising navigation and reducing deployment time.

This feasibility study was a follow-on activity from an initial SAIC-funded project. A second follow-on project (Seafood Innovation Fund full R&D project) will take the project further to develop these technologies for industry use. 

The full title of this project is ‘Georeferenced 3D photogrammetry: a tool for monitoring finfish aquaculture impacts on hard seabeds (feasibility study)’.

Read the case study