Rhode Island's Tropical Visitors

A particularly remarkable specimen – a red lionfish, native to the Indo-Pacific – apparently drifted up to Jamestown, R.I., in 2006. It's still on display at the Seacoast Science Center in Rye, N.H. It's not rare to see lionfish in the North Atlantic any more. Over the past 16 years, an influx of these venomous fish has been seen along the Atlantic coast around North Carolina and Long Island, N.Y., and as far north as Massachusetts.

Mr. Gardner says he caught the first lionfish spotted off Long Island in 2001. And in 2006, the southern bays along Long Island's coast were filled with baby lionfish that arrived via the Gulf Stream. This year, though, he hasn't found any lionfish. Because the Gulf Stream current is located 200 miles off Long Island, the fish that arrive along the North Atlantic coast vary from year to year. Gardner says it all depends on the contents of the small pockets of warm water from the Gulf Stream that are blown into shore every summer. "The mix of fish that we get here is almost arbitrary," he says.

No one is sure how the lionfish invasion began, but Gardner notes that researchers began to notice an increase in the species after Hurricane Andrew in 1992. "Certainly lionfish were introduced into the Atlantic by someone or some group of people," he says. They could not have swum or been carried by the current from halfway around the world. "Some people say it was an aquarium that got washed into an ocean," he says.

James Morris, an ecologist at the National Oceanic and Atmosphere Administration, notes that the "lionfish are fairly low in abundance" in northern waters and don't pose any threat as fall nears.

While warmer-water species are increasingly found farther and farther north, tropical fish haven't been able to establish themselves in colder climes past October and November, when the ocean temperature drops below 60 degrees F. That's why the summer months are treasured by divers at Fort Wetherill.

The stray tropical fish lured crowds there on a recent Saturday afternoon. In one corner of the parking lot, Scott Tucker and Chris Pimley of Connecticut strapped on scuba gear. They met at this rocky cove four years ago, drawn by their love of nature and documentary filmmaking. Today, they are preparing to film tropical fish for a public-access television show. Across the way, divers Diane Malczewski of West Greenwich, R.I., and Charlie Jennings of Fall River, Mass., sit on the back of a pickup truck and show off a jar holding a small, captured trunkfish they planned to take home.