Dead porpoise in Finland may provide vital data for critically endangered species

A harbour porpoise that died on Finland’s Ostrobothnia coast could offer researchers unprecedented insights into the critically endangered Baltic Sea population, according to marine mammal expert Olli Loisa of Turku University of Applied Sciences.

The animal, found dead in Vöyri’s Maksamaa on Saturday, likely succumbed to severe skin lesions and inflammation caused by exposure to freshwater—a fatal condition for the species. With fewer than 500 individuals remaining in the Baltic Sea population, this specimen presents a rare opportunity for study.

“A freshly deceased porpoise has never been examined in Finland using current methods,” Loisa stated. The Finnish Food Authority’s Oulu laboratory will analyse tissue samples to determine the cause of death, diet, and environmental toxin levels—key factors threatening the species’ survival.

The porpoise, first spotted in late April near Vassor in Ostrobothnia, was closely monitored throughout its three-week stay. Researchers documented its movements, behaviour, and deteriorating health, including its migration up the Kyrönjoki River. Genetic samples will also confirm its population origin.

While relocation to saltier waters was considered, Loisa noted the 500-kilometre journey to the Åland Islands posed too great a risk. “Capture and transport would have been painful,” he explained. “Natural death was the most humane outcome.”

Local fishermen provided critical observations, aiding researchers in tracking the animal’s final days. Results from the international collaboration will be released later.