The alarm came at around 3 pm and several police patrols went to the scene.
They stated that it was very much a body part from a human lying in the water.
The body part has now been transported from the site and is now going to the Forensic Medicine Agency for analysis.
Since crime cannot be ruled out, a preliminary investigation into murder or causing another person's death has been initiated.
At the beginning of May, body parts were also found in Oxelöund's harbor.
They could then be identified and turned out to belong to a man in his 80s.