Hartwin the humpback whale returns to Danish waters after brief incursion into the German Baltic Sea

An adult humpback whale named Hartwin, identified by its distinctive half‑white, blistered back, entered German waters near Holnis in the Flensburg Fjord on 5 July after moving south from Danish waters. The sighting raised concerns that the whale could suffer the same fate as the recently stranded Timmy, prompting calls for a cautious approach.

On 9 July the conservation group Stranded No More announced that Hartwin had retreated to Danish waters, being spotted in the harbour of Aarhus and later near the island of Tunø. Marine biologists urged vessels to maintain at least a 50‑metre distance, warning that the whale’s weakened condition and probable parasite infestation could lead to drowning or stranding within weeks. Experts warned that without deeper water the whale is likely to die.

The incident highlights ongoing challenges in managing marine wildlife health in the Baltic Sea region.