Historic Newspaper Archives Reveal Past Porpoise Distributions in Baltic Sea

A recent study published in Ecology and Evolution utilized centuries-old newspaper clippings from Sweden to reconstruct the historic distribution of harbor porpoises in the Baltic Sea. Researchers from Denmark and Sweden analyzed digitized archives from the 1700s to the early 1900s, identifying 1,490 mentions of porpoises using keywords like tumlare and marsvin. The findings indicate that harbor porpoises were once widespread along the entire Swedish coastline, including the Gulf of Bothnia, and in German, Lithuanian, and Latvian waters. Today, the Baltic Proper harbor porpoise population is critically endangered, with only about 500 individuals remaining, occupying merely a third of their original range. The decline is attributed to fishing, contamination, and noise pollution. Although newspaper accounts lack the precision of modern scientific surveys, they provide unique historical data inaccessible through other means. The study highlights the significant impact of human activities on marine mammal populations and calls for proactive protection and management strategies to reverse the current declining trend and conserve this imperiled species.