Guest blog by Yann Rouxel, Bycatch Project Officer.

After years of research and limited successes in finding a solution to the accidental catch of seabirds from gillnet fisheries, a new floating device might be part of the answer to this problem. A new paper hot off the press shows that our new device, called the Looming-Eyes Buoy (LEB), could reduce the abundance of a vulnerable species from diving near gillnets.

It is estimated that about 400 000 seabirds are being bycaught each year in global gillnet fisheries. A serious conservation issue for many vulnerable seabird species including Black Guillemots, Long-tailed Ducks or Velvet Scoters. Nobody has ever been able to find an effective mitigation measure working across species and gillnet fisheries, however. Implementing fisheries closure in certain areas or switching gillnets to other gears could in theory tackle this problem. But reluctance from the fishing industry and difficulties in implementing such measures without causing serious collateral impacts, has meant that development of such measures has been particularly limited. And in the meantime, birds keep getting bycaught.

A Velvet Scoter bycaught in a Baltic sea gillnet fishery (c) Julius Morkūnas 

Developing a “scarecrow at sea”

In contrast, technical mitigation measures (e.g. small alterations to the net) are more likely to be accepted as long as they do not negatively impact fish catches. With this in mind, and the experience from previous projects testing underwater mitigation measures in the Baltic sea (here), we explored the potential use of devices which could prevent birds from diving near gillnets in the first place. Simply put, this device aims at being a scarecrow for fishers by using the effect of large eyespots and looming movements to act as a natural visual deterrent for birds. Our idea was then, if we can reduce the chances of seabirds from diving too close from gillnets, we could prevent deadly interactions from happening!

Looming-eyes Buoys (LEB) deployed in the Küdema bay, Saaremaa, Estonia. Photo: Ainar Unus

That was the concept, but of course we still needed to test it in real life conditions! After a collaboration with the marine engineers of Fishtek Marine to develop the LEB device, we were able to secure funding from the National Geographic Society and develop a collaboration with the Estonian Ornithological Society, to test its effectiveness in real marine conditions. From February to April 2020, we measured the effect of our LEB devices on birds abundance in an important wintering ground for seaducks in the island of Saaremaa (Estonia), in the eastern Baltic sea.

Promising results

With 250 hours of observation and the count of over 10,000 seabirds, our results indicated that LEB devices can reduce the abundance of Long-tailed Ducks by about a quarter (within a 50m radius), compared to traditional fishing buoys. Importantly, we found no evidence for a memory effect on long-tailed ducks (individuals still avoiding the area even after the removal of the device) but found some habituation to the LEB within the time frame of the project. This indicating that potential deleterious effect on birds is probably minimal and restricted in time and space.

Field work team conducting birds counts around the Looming-eyes buoys and normal buoys, in the Küdema bay, Saaremaa, Estonia. Photo: Yann Rouxel

Tests in a commercial fishery needed

Either way, follow up testing – this time in active gillnet fisheries – is absolutely needed. Fortunately, we were able to secure funding from the Marine Stewardship Council Science & Research Fund to confirm, whether or not, LEBs can significantly reduce seabird bycatch from gillnets. This new project will be starting in late 2021 and run until late 2022, in the Icelandic Lumpfish fishery. If proven effective, this new measure could help save thousands of seabirds each year around the globe and contribute to making our ocean safer for seabirds.

Colleagues from Lithuania and Portugal are also exploring similar approaches, using kites in the form of birds of prey to deter seabirds from getting too close to the fishing gear (here). And they had some promising results so far! More soon, so stay tuned!

We are particularly grateful for the funding support from the National Geographic Society which allowed us to carry out this work in Estonia, as well as the support from the Baltic Sea Foundation to cover the development and production of the Looming eyes buoys. Sincere thanks are due to our fieldwork team—Andres Kalamees, Andrus Kuus, Mati Martinson, Rein Nellis, Maarja Nõmm, Maris Sepp and Ainar Unus—and the Estonian Environmental Agency, without whom this project would have not been possible.

Continue reading

 Would you like to be kept up to date with our latest science news? Email with the heading 'enewsletter' to be added to our quarterly enewsletter.

Want our blogs emailed to you automatically? Click the cog in the top right of this page and select 'turn blog notifications on' (if you have an RSPB blog account) or 'subscribe by email'.

Anonymous