The researchers say they have found colonies of invasive sea squirts, blob-shaped animals that reproduce easily, on the floor of the sound.
They believe this variety of sea squirt, known as didemnum, arrived on the hulls of ships from Asia. They have no known predators.
"This thing has the potential for causing significant economic impact when it attaches to the floor of the Sound, where it blankets and suffocates shellfish and lobsters," said Ivar Babb, director of UConn's Undersea Research Center at Avery Point in Groton.
The animals range in color from a creamy translucent pearl to olive or tan. In Japan, there are some red species.
"This thing is ugly," Babb said. "It has no socially redeeming virtues."
The UConn researchers, who want to document how much of the Sound's floor the sea squirt blankets, went out Tuesday on UConn's 72-foot coastal research vessel.
Using a remote-controlled robot, they began mapping a region of about 1 square mile near Fisher's Island, taking pictures and video.
"We are seeing some large colonies of these sea squirts," said Robert Whitlach, a professor of marine sciences at UConn at Avery Point, who was on board the boat Tuesday afternoon. "Sometimes they are a few inches in diameter; other times they are a mat 4 to 5 square feet."
They cannot break the colonies apart, Babb said.
Like sea stars that become damaged, they can grow replacement parts. Splitting one sea squirt in half doesn't kill it; it only creates two of the plankton-eating creatures.
If the scientists don't find bigger quantities of the blob-like creature, they might use chlorine or vinegar to kill it. First, however, they plan to study the effect those substances might have on other marine life native to the Sound.