Underwater survey finds Plum Island to have wealth of animal, plant life

The islands extending off Long Island's North Fork, including Plum Island, are known as areas of ecological importance. However, there has been very little effort to gather detailed information on the habitats sustaining the surrounding marine diversity.

A team of divers and marine scientists conducted what's described as a first-of-its-kind survey of the underwater habitats around Plum Island in September. They found those waters to be packed with life.

The weather conditions allowed for four days on and in the water.

Findings from the exploration are detailed in a recently completed report titled "Initial Survey of Plum Island's Marine Habitats." The study was supported by Save the Sound, New York Natural Heritage Program, and New York State Department of Environmental Conservation and funded by an anonymous donor.

Naturalists consider the area to be of ecological importance because it supports a diversity of at-risk species that may rely on the habitats and island for protection and food.

Divers discovered four generally distinct areas in the region. The first was a relatively flat, large expanses of gently sloping coarse grained sandy areas with distinct sand ridges. The second, dense assemblages of boulders that were 2–4 meters across with smaller boulders, large stones, and crevice spaces between them. Third, occasional assemblages of large stones and boulders unconnected with each other scattered about in large expanses of open sandy areas. Lastly, eelgrass meadows in a relatively shallow nearer shore area off the west side of Plum Island.

Researchers say throughout all four areas, wherever boulders or rocks are present, virtually every surface is covered in kelp, bryozoans sponges, or northern star cora.

At the southeasternmost end of the island, mussels attach to the tops of boulders at or near the surface, making for layered biological communities. Fishes also congregated around boulders and other relatively large stone structures.

A second study is currently planned for the summer of 2021.