Plum Island marine survey finds abundance of animal, plant life

The waters surrounding Plum Island, one of the more mysterious areas in New York State, are a little less of a mystery now.

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

Findings from their exploration over five days last September are detailed in a recently completed report titled “Initial Survey of Plum Island’s Marine Habitats.” The study, supported by Save the Sound, New York Natural Heritage Program, and New York State Department of Environmental Conservation and funded by an anonymous donor, reveals an abundance of animal and plant life in a wide range of habitat types off the island’s shores.

Most of Plum Island has been allowed to be without much disturbance for the last 70 years, ever since the Army left in the early 1950s. It’s a place where wildlife has returned, and the fact that it’s there in such diversity is fabulous.

Louise Harrison

“I have seen many parts of Long Island Sound over my long diving career, and I have never seen anything quite like it, particularly on the northern side of the island,” Steve Resler, one of the divers who conducted the survey, said in a Save the Sound press release last Thursday. “Every centimeter of hard substrate was covered with plant and animal life, and some of the boulders were four meters across. It was extraordinary and thrilling for me.”

In a phone interview with The Suffolk Times on Monday, Mr. Resler said his “every centimeter” quote was “not an exaggeration. Every single hard substance, every rock, everything bigger than pebbles — even pebbles — was covered, encrusted with organisms … It’s just absolutely fantastic.”

Plum Island, located in Gardiners Bay, east of Orient Point, is three miles long and one mile wide at its widest point. It is home to the Plum Island Animal Disease Center, established by the United States Department of Agriculture in 1954 and for years a source of controversy and mystery. Little had been known about the subtidal marine habitats and benthic species surrounding the island.

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.

“Most people think of exotic tropical reefs when they think of coral, but we are lucky enough to have a species of shallow-water coral in Long Island Sound,” Emily Runnells, a marine scientist for New York Natural Heritage Program, said in the release. “It’s great that we’ve discovered the northern star coral living around Plum Island, which is one of the few places in New York that has the shallow, rocky habitat it needs. This same kind of coral also lives in the tropics, so if we can learn the reasons for its adaptability to the range of temperatures it experiences in Long Island Sound, that knowledge may someday allow us to help struggling tropical coral reefs. More study needs to be done, and Plum Island’s waters could be a living laboratory for that work.”

Also found were communities of sponges, bryozoans, and tube worms covering immense boulder fields, coral, anemones, eelgrass meadows and blue mussels. The researchers encountered gray seals, including one that Mr. Resler said pulled on one of his swim fins. Various species of red and green algae, along with sugar kelp around most of the island, were also seen. It may be one of the few places in New York where kelp beds thrive.

“We thought that kelp may be growing in significant quantities around Plum Island—and we found it,” Mr. Resler said. “Here though, the kelp doesn’t stand in tall vertical columns like in the Pacific Northwest. Instead it sways almost horizontally due to the very strong tidal currents around the island.”

Louise Harrison, New York natural areas coordinator for Save the Sound, said 227 bird species, nearly a quarter of all bird species in North America (excluding Mexico), have been seen on Plum Island, which comprises only about 822 acres.

“When you think of something that’s so small and yet it has such high diversity, you wonder why, and we’re beginning to learn that it’s a combination of many elements,” Ms. Harrison said in a phone interview. “It’s the clean waters that are coming in from the Atlantic Ocean. It’s the estuarine waters leaving Long Island Sound and the Peconic Estuary and the mixing that goes on between the Peconic Estuary and Long Island Sound, the high oxygen level coming in from the Atlantic Ocean, and the lack of disturbance. Most of Plum Island has been allowed to be without much disturbance for the last 70 years, ever since the Army left in the early 1950s. It’s a place where wildlife has returned, and the fact that it’s there in such diversity is fabulous.”

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

Save the Sound said it wants to protect the ecosystem at federally owned Plum Island, which is slated to be sold at auction after the Plum Island Animal Disease Center moves to Kansas. A vision report for the island’s future, developed by Save the Sound and The Nature Conservancy, is said to be nearing completion. “We know that the more we learn about the ecosystem, above and below water, the greater our chances of making a compelling case for preserving this amazing ecosystem,” said Ms. Harrison.

She added, “Everything about Plum Island is amazing, and you can’t stop being fascinated by it.”