Baltic seaduck take a dive

On Wednesday 1 December, a new report presenting the results of a census of wintering waterbirds in the Baltic Sea has been launched. The studies reveal that overall numbers have declined by more than 40% since the 1990s.

To read the full report Waterbird populations and Pressures in the Baltic Sea, please click here
Internationally coordinated counts were undertaken in 2007-2009 under the SOWBAS project (“Status of wintering waterbird populations in the Baltic Sea”), funded by the Nordic Council of Ministers. The total number of wintering waterbirds was estimated at 4.41 million, compared to 7.44 million during the last census in 1992-1993.

Of the 20 species covered, 11 decreased, including 7 that declined by more than 30%. The strongest declines were suffered by seaduck. Numbers of Long-tailed Duck, the most numerous wintering waterbird in the Baltic, declined by 65%, with similar declines recorded for Steller’s Eider (Vulnerable) and Velvet Scoter. Common Eider, Common Scoter and Red-breasted Merganser all declined by between 42% and 51%.

For some of these species, the Baltic is the most important wintering area in the world, holding the majority of their global populations. These declines are therefore of global concern, and could have implications for the species’ status on the IUCN Red List.

BirdLife has combined these results with available data from other parts of the world to review the species’ global status and propose appropriate changes. Detailed proposals are available for comment (until January 2012) on BirdLife’s Globally Threatened Bird Forums: http://www.birdlife.org/globally-threatened-bird-forums/

Most of these seaduck concentrate in the southern Baltic, but unlike some other waterbirds, no consistent climate-driven northward shift in their winter distribution was detected. However, climate change may be affecting them in other ways. Many of these species breed mainly in the Russian arctic or tundra, where they may be suffering from climate-induced ecosystem changes. Recent monitoring in autumn, as these birds arrive in the Baltic, has revealed worryingly low proportions of juveniles, implicating unsustainably low recruitment on the breeding grounds.

Other factors could also be involved, such as over-harvesting of certain species, or oil discharges from ships, which are known to cause significant extra mortality in some parts of the Baltic. Changes in nutrient loads could also be having an impact, and the report stresses the importance of eutrophication in determining food availability and thus the abundance and distribution of waterbirds. Finally, incidental bycatch in gill-nets has been reported in several Baltic fisheries, with diving species like seaduck being particularly susceptible.

Now that the trends of these species are known, the top priority is to diagnose and address the causes of their declines. Experience suggests that this is best achieved by bringing together key experts from across the species’ range to make progress in a coordinated and effective manner, at a flyway population scale and with international cooperation.

Discussions to organise a conservation planning workshop in 2012 have already begun, involving the IUCN-SSC/WI Duck Specialist Group, the Wildfowl & Wetlands Trust, BirdLife International, Wetlands International and the African-Eurasian Waterbird Agreement.

http://www.birdlife.org/community/2011/12/baltic-seaduck-take-a-dive/