It may not be a new marker. We were over in Roberts Cove and as we came out of Roberts Cove with Plum Island on our right and the shore on our left, there was a second red top marker by the island. A quick look around and it became evident that the red top marker that defined the south end of the shoal area along with the black top and flasher marker at the entrance to Roberts Cove was missing. It obviously came loose from its mooring and drifted farther in to the cove.
I made a call to Marine Patrol and it was replaced the next time we came back out that way a few days later.
Look around and make sure the marker hasn't arrived from another location
.