If I'm correct the Island you are talking about runs parallel with Harrison Bay park. On the surface it is mabe 40 feet at best in diameter. The Blue Harrons nest there and I don't think is posted. It is very shallow both above and below with it sloping off on both sides. The Island is very small, but the shallow region extends about a half mile up and down stream from the island. If this is the right island it was very dense in growth the last time I looked, but I didn't pull ashore and get out of the boat. I know the water was 2 feet deep about 20 feet or less from the island.