Footage filmed in Crosby this morning shows what looks like "the plug being pulled out of the sea".
The video show a huge green stopper-type object being removed from the water – and it has caused some confusion.
A man who was walking along the front at Hall Road this morning said: "It looked like a digger was pulling a big green plug out of the sea. The tide is really low today, as well, so it actually almost looks like that's what's happened."
But Sefton Council has clarified the situation.
A post on their Green Sefton Facebook page says: "Come in number C7 your time is up…
"Everyone relax, the plug hasn't come out of Liverpool Bay just yet, but one of the navigation buoys in the Mersey approaches has broken free of its moorings.
"The buoy was recovered and carefully rolled onto a low loader this morning at Hall Road before removal."
Buoys are used to mark the shipping route approaching Liverpool, which follows the Queen's Channel, the Crosby Channel, and the River Mersey.
The channels run between tall training banks that channel the scouring effects of the tide to keep the deep water approaches to Liverpool open.