Study details Plum Island's rich underwater ecosystem

Four scientists went on a deep dive in the waters off Plum Island last summer to better understand and preserve an underwater ecosystem largely untouched by humans.

The results were unveiled earlier this month in a 33-page report from the New York Natural Heritage Program and sponsored by the nonprofit Save the Sound through donors. It is titled “Survey of Plum Island’s Subtidal Marine Habitats.”

As federal officials prepare to move the USDA operation there to a new facility in Manhattan, a city in Kansas, the Preserve Plum Island Coalition hopes the study will strengthen its effort to preserve the natural beauty and marine life in the 800-mile landmass and its surrounding waters.

The information gathered in August could serve as the foundation for future environmental studies, said Louise Harrison, New York Natural Areas coordinator for Save the Sound, which coordinates the Preserve Plum Island Coalition.

Advocates are also hoping the island could become a nationally protected park or monument. The more data the coalition has, the better equipped it will be to convince authorities of Plum Island's ecological importance.

“Letting the world know how biologically diverse Plum Island is from top to bottom … helps to make the case for preserving it,” Harrison said.

InnerSpace Scientific Diving of Albany was contracted to do the work Aug. 2 through 6 which expands on a similar 2019 dive.

The number of species found during the 2021 dive doubled from the 2019 collection, from about 60 to 126. New finds include the lined anemone, a translucent white creature that is sometimes found off other parts of Long Island, but wasn’t seen in 2019. Thousands were spotted in 2021.

Species were stored in plastic bags and vials and then transferred to Cornell Cooperative Extension researchers for preservation.

The scientists said almost all locations were teeming with life but referenced a “wow site” they discovered on the final day of the dive that was full of undersea creatures.

“We wish we had had more time to go back in” said Innerspace Scientific Diving owner Steven Resler. “It was loaded with anemones and sponges in numbers we didn't see anywhere else.”

At one point sampling was cut short when divers spotted gray seals nearby. The animals are suspected of stealing the contents of a mesh bag of samples and tools that went missing while the researchers were working. The bag was later recovered, Resler said.

What divers did not find were signs of pollution or human impact. Resler said the researchers didn’t find as much as a piece of fishing line during the dive.

Plum Island’s coast and waters encompass several habitats rare for Long Island, including eelgrass meadows, rocky intertidal areas, and subtidal areas with large boulders. It’s also the largest seal haul out site in New York.

“Our scientists discovered a world of underwater biodiversity that few people get to see,” Matthew Schlesinger, chief zoologist at the heritage program said in a news release. “Plum Island’s waters are home to a surprising diversity of life, existing mostly undisturbed beneath the surface. Our body of knowledge about this unique place continues to grow.”

By Vera Chinese

vera.chinese@newsday.com@VeraChinese

Vera Chinese joined Newsday in 2017 after working as an editor for the East End lifestyle publication northforker and a general assignment reporter for the New York Daily News.