Rhode Island’s tropical visitors
From July through September, scuba divers and snorkelers converge in the parking lot at the Fort Wetherill State Park to explore the underwater world. But some are here for a rather unexpected reason: the tropical fish.Skip to next paragraph
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For years, scientists and avid divers have come to this rocky cove in Jamestown, R.I., to try to catch a glimpse of spotfin butterflyfish, snowy groupers, and other tropical varieties carried north from Florida and the Caribbean by the Gulf Stream.
“It’s not a new phenomenon,” says David Beutel, a Sea Grant fisheries extension specialist at the University of Rhode Island, Kingston (URI), but people who are used to seeing only native fish like cunner and striped bass may be surprised. “I don’t think the average person would know,” Mr. Beutel says.
During the summer, storms create warm-water eddies that split off from the Gulf Stream, carrying millions of eggs or thumbnail-size young tropical fish on a 1,500 to 2,000-mile journey up the Atlantic coast as far as Buzzards Bay, Mass.
Professor Collie says there’s been an increase over time, in tropical fish in Rhode Island waters since the university began trawling for fish in two locations in Narragansett Bay in 1959. One reason is warmer water, he says: The average temperature of Narragansett Bay has risen four degrees F. in the past 50 years. That encourages warmer-water species like butterfish and scup while also discouraging cold-water varieties such as winter flounder and silver hake. Changing fishing practices and a shift in the ecosystem are other possible factors for the decline of cold-water fish in the Bay and the rise of warmer-water ones, Collie adds.
The array of tropical fish arriving along the North Atlantic coast has grown in the past few years. Some tropical fish have been found as far north as Nova Scotia and Maine, says Todd Gardner, a biologist at the Atlantis Marine World Aquarium on Long Island, N.Y.
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.