A humpback whale stranded on Germany's Baltic Sea coast has freed itself and swum into deeper waters after days of rescue efforts, with experts continuing to discuss the whale's initial intent.

German authorities and rescue teams are continuing their efforts to free a 15-meter humpback whale stranded in the shallow waters of the Baltic Sea, but experts fear the chances of saving the 15-ton mammal are slim after several attempts have failed.

A humpback whale remains stranded in shallow waters off Germany's Baltic coast, with rescuers racing against time to save the animal after initial attempts failed. New equipment is being deployed as experts warn of imminent death without aid.