Water deterrent device:Reducing seabird bycatch in demersal trawl fisheries

Solution developed by

Seabird bycatch remains a significant environmental challenge in demersal trawl fisheries, as birds are attracted to fishing vessels and gear during operations, increasing the risk of collision or entanglement.

The MarineGuardian water deterrent device aims to reduce these interactions by discouraging seabirds from approaching active fishing gear, without interfering with fishing operations.

The challenge

During demersal trawling, seabirds often follow vessels to feed on discards or bait. This behavior exposes them to a high risk of accidental bycatch, especially during gear deployment and hauling.

One bird, the Northern Gannet (Morus bassanus) is specifically targeted as it is already on the European Red List of Birds from the IUCN and is a known bycatch specie in demersal fisheries.

Northern Gannet by Andreas Trepte – Own work, CC BY-SA 2.5, https://commons.wikimedia.org/w/index.php?curid=339367

The solution

The water deterrent device combines:

  • Visual deterrents, which create a visible disturbance on the water surface to alert and discourage seabirds
  • Physical barriers, which limit birds’ access to high-risk areas around the fishing gear

Together, these elements reduce seabird presence near the trawl while remaining practical and compatible with commercial fishing operations.

Development and progress

The water deterrent device is being developed in close collaboration with the fishing sector:

  • Initial internal meetings and first exchanges with industry stakeholders have been completed to assess operational constraints and feasibility
  • Early 2026: adaptation of the technology for use on a demersal trawl vessel
  • June 2026: planned sea trials on a scientific vessel to test effectiveness and operational performance

Expected impact

By reducing seabird interactions with trawl gear, the water deterrent device contributes to:

  • Lower seabird bycatch rates
  • Improved compliance with conservation objectives
  • More sustainable demersal trawl fisheries