Scientists said the critically-endangered species had previously only been found in rivers and know pearl mussels have been discovered in the Scotland Lochs.

Recent heat waves have warmed Lapland’s rivers and lakes, leading Metsähallitus to suspend fishing permits and advise against salmonid fishing in the warm waters.

Lake and river surface waters in Lapland have warmed rapidly due to recent heatwaves, reaching up to 5°C above average and attracting more beach visitors than usual.

The Finnish Meteorological Institute reports that July 2025 was exceptionally warm across Finland, with Lapland’s Ylitornio experiencing a record 26-day heatwave.

Northern Finland experienced unprecedented June temperatures and abnormal rainfall, deviating significantly from historical weather patterns.