Rare porpoise sightings in Finland coincide with researcher’s absence

Finnish marine biologist Olli Loisa is missing a once-in-a-lifetime opportunity as multiple harbour porpoises—one of the Baltic Sea’s most endangered species—have been spotted along Finland’s Ostrobothnia coast and in the Kyrönjoki River this week. Loisa is currently attending a whale research conference in Scotland, he told national broadcaster Yle.

“It’s frustrating,” Loisa admitted. “I’d love to observe them myself, but fortunately, our research team was able to head out early this morning to document the sightings.”

The appearances are highly unusual. Harbour porpoises, of which only around 500 remain in the Baltic, are rarely seen this far north. Their core habitat lies in the shallow waters between Sweden’s Gotland and Poland, making these observations “truly exceptional,” according to Loisa.

If several individuals have traveled to Ostrobothnia, they could represent a significant portion of the entire Baltic population. While the exact reason for their northern migration remains unclear, Loisa suggests food availability may play a role. “Porpoises are opportunistic feeders,” he explained. “They eat whatever small fish are abundant—like the spring herring spawning in river estuaries right now.”

The sightings have drawn widespread public interest, but Loisa urges caution. “People need to keep their distance,” he stressed. “These animals are extremely sensitive to disturbance, especially while feeding or socializing.” He advises boaters to stay at least 100 meters away and asks fishermen to temporarily remove nets from the water to prevent accidental entanglements.

“Every individual counts when a population is this critically endangered,” Loisa said. If a porpoise is found dead in a net, he asks the public to immediately report it to Finland’s Natural Resources Institute (Luke), as researchers lack tissue samples from the Baltic population. “We rely on these reports—no one should withhold this kind of information.”