These islands include Fire Island, the largest of the outer barrier islands that parallels the southern shore of Long Island for approximately 31 miles ; Plum Island, which was home to the Plum Island Animal Disease Center, a biological weapons research facility; as well as Robins Island, Gardiners Island, Fishers Island, Long Beach Barrier Island, Jones Beach Island, Great Gull Island, Little Gull Island, and Shelter Island.