In March 2021, the Sussex Nearshore Trawling Bylaw banned trawling along the Sussex coastline. The aim was to allow the kelp forest ecosystem that once thrived in these waters to recover over time.

To track that recovery, the University of Sussex compared NatureMetrics’ eDNA metabarcoding service with traditional visual surveys, as part of a multi-year project monitoring biodiversity inside the trawling exclusion zone. eDNA detected three times as many marine vertebrate species, using a fraction of the time and effort.

Monitoring marine recovery efficiently over many years

Tracking biodiversity recovery after the trawling ban needed reliable monitoring that could be repeated over multiple years. Traditional methods such as baited remote underwater video (BRUV) are costly and labour-intensive.

The University wanted to know whether eDNA could offer a more efficient alternative. It set out to compare the two approaches directly within the exclusion zone.

NatureMetrics provided an easy-to-use, cost-effective and time-efficient eDNA solution for monitoring biodiversity change along the Sussex coastline as the ecosystem recovers.

The University chose our eDNA metabarcoding service for this multi-year project because the method is easy to replicate. Its simple sampling procedure also meant students could carry out the fieldwork themselves.

• More species detected: eDNA detected three times as many marine vertebrate species along the Sussex coast as BRUV surveys.
• Less effort per site: eDNA took 25 minutes per survey site, compared with 7 hours for visual surveys (including fieldwork and data processing).
• Less effort per species: eDNA took 1.25 minutes per species detected, compared with 8 hours for visual surveys.

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Stronger evidence for marine protection

• A proven tool for tracking recovery: The results show that eDNA is a powerful biomonitoring tool for tracking biodiversity recovery along the Sussex coast.
• Evidence to support future protection: Robust biodiversity data is important for conservation, and for justifying future bylaws and Marine Protected Areas.
• Major time and cost savings: eDNA cut survey effort from hours to minutes, making long-term monitoring more efficient and cost-effective.
• Monitoring anyone can carry out: Simple sampling meant students could collect the data, making the approach easy to repeat year after year.