The Baltic Sea is a global hotspot for seabird bycatch, with an estimated 76 000 birds caught in fishing gear every year. It is mainly in the coastal gillnet fisheries that diving ducks and other seabirds get entangled, heavily reducing bird populations and causing grief and extra work for coastal fishermen. In a new collaboration, BirdLife International is trying to tackle this issue together with a group of Lithuanian fishermen.
Seabird bycatch is a global problem and occurs to some extent in many fisheries. It is one of the main threats to bird populations and a recognised conservation issue. In efforts to tackle these problems, there has been much focus on bycatch in industrial longline and trawl fisheries, while the small-scale gillnets have been somewhat overlooked. It is therefore particularly welcome that a project aiming to find practical solutions has been initiated recently in Lithuania. It is a collaboration between BirdLife International and a group of Lithuanian fishermen. Together they will be testing gillnet modifications in order to reduce bycatch of seabirds.
In the Baltic Sea, nearly 3 million sea ducks overwinter – all under the protection of the EU Birds Directive, with some species specifically listed in Annex 1. All these seabirds are exposed to a number of risks, including climate change, invasive species such as the American mink, hunting and eutrophication, as well as bycatch in fisheries.
An estimated 76 000 birds are caught in fishing gear in the Baltic every year. With a global estimate of bird bycatch at 400 000 birds, this makes the Baltic Sea a hotspot, with gillnet bycatch likely to be one of the contributing factors in the severe declines in sea duck numbers in the region.
In 2012, the European Commission adopted the EU Action Plan for reducing seabird bycatch (COM(2012)665), with its central aim to “minimise and, where possible, eliminate bycatch”. One of the key actions of this plan is to instigate research into mitigation measures for gillnets. Bycatch-reducing solutions have already been developed and tested for longlines and trawls, but for gillnets, we do not have a suite of practical technical measures that can be adopted. There is still a great need to develop such tools to bring down the substantial numbers of birds dying in this gear.
Technical modifications to fishing gear
There are several avenues worth exploring: temporal and spatial closures, gear switches (for example to traps and pots), and technical modifications to the gear itself. Technical modifications are likely to be most popular with fishers – if you can reduce bycatch but maintain target catch. The following technical modifications have been investigated globally:
1. Pingers – tuned to a lower frequency than usually used to deter marine mammals. Such methods showed promise for reducing common guillemot bycatch in the US.
2. Trials of mixing metal oxides in the net materials to increase reflections and make nets more detectable to birds and marine mammals. The results have been somewhat inconclusive, and some tests have resulted in greatly reduced catch.
3. Increasing the visibility of gillnets: a J-net design has been trialled in a salmon fishery in the north-east of England, coupled with increased attendance of nets, and removing them at night.
4. US trials in the Puget Sound sockeye salmon fishery tested two depths of high-visibility panels: 20 and 50 meshes deep – both reduced bycatch of birds but the deeper mesh also reduced the fish catch, whereas the 20 mesh section reduced bycatch of guillemots while maintaining fish catch.
In Lithuania, BirdLife and fishermen are testing the use of white sections of netting across the top section of bottom-set cod nets, akin to those tested in the US salmon fishery, to increase the visibility to birds.
These trials started just a few weeks ago; early tests reduced the fish catch too much, so they are now making some further modifications to the nets.
It has also been a difficult year to start trials, as the mild climate and other factors have resulted in greater dispersal of birds across the Baltic, meaning that overall bycatch of birds has probably been lower this past winter. This makes it difficult to assess the effectiveness of the trials. Irrespective, the impact of net modifications on target catch is still critical to understand, and plans are afoot to conduct further trials this autumn/winter.
Creating a Seabird Task Force for the Baltic
The ongoing Lithuanian study is very small compared to the extensive body of scientific literature on seabird mitigation for longlines and trawls. According to Rory Crawford at BirdLife International, a similar range of practical trials in the EU would be warranted, but for some reason this is not happening.
BirdLife International is hoping to create a Seabird Task Force for the Baltic – a collaboration between fishermen, net-makers, NGOs and scientists in order to tackle the widespread bird bycatch problems. The new European Maritime and Fisheries Fund (EMFF) can potentially fund such collaboration projects, at least at national level.
If you or your organisation is interested in such collaborative work, contact Rory Crawford at BirdLife International: rory.crawford@rspb.org.uk
For more information see links and document below.