Population of Harbour Porpoises in the Baltic Sea diminishes

Quickborn (dpa) -

According to marine conservationists, the number of harbour porpoises in the Baltic Sea is diminishing continuously. ‘Particularly alarming is the development in the inner Baltic Sea (East of Rügen), where only an estimate of 250 adults are left’, says Petra Deimer, Chair of the Society for the Conservation of Marine Mammals (GSM), last Friday. She referred to the results of a Working Group of the Jastarnia plan. This recovery plan for the only domestic whale in the Baltic Sea was established 10 years ago and the majority of the bordering countries are members .

Also in the Danish part of the Baltic Sea, the numbers have dropped substantial ly. ‘Whereas the estimated number of harbour porpoises for 1994 for the Belt
(Kattegat, Belt, Sund und Western Baltic) were 27 769 animals , for 2005 a number of 10 865 animals was estimated only’ , The Society for the Conservation of Marine Mammals (GSM) writes referring to a PhD Thesis by Signee Sveegaard of the Danish University of Aarhus .

On top of that, tourists and water sports enthusiasts have reported a number of
approx. 170 strandings (dead harbour porpoises) annually during the past three years on German Baltic Sea beaches. ‘More than half of them are bycatch’, Petra Deimer says, referring to investigations of the Research und Technology Centre (FTZ) in Büsum. ‘This unnatural mortality rate is far too high and should normal ly be under 1 percent of the healthy population.’

Reasons for the diminishing population of the harbour porpoise are mainly bycatch but also marine pollution, mineral extraction and increasing shipping traffic. The Jastarnia Group, recommends sustainable fishing gear for instance fish traps instead of stel lnets which can be lethal to marine mammals and seabirds.