Because Cumberland Island is isolated from the Georgia coast and the U.S. National Park Service manages the island as a designated wilderness area it is one of the most undeveloped shorelines on the eastern coast of the United States.
They have this ability because the parts that are shiny are meant to be like bait for other animals and when they come near to eat it or check it out they get eaten by the entire fish which is much larger than its bioluminescent part.