Digital Extra

The giant craft was hulking off fragile, beautiful Trustom Pond, centerpiece of a national wildlife preserve near Moonstone Beach.

The beach itself is a nesting site for the federally protected piping plover.

Last night, the burning tugboat that had been towing the barge was lying just 50 yards from a rope outlining the area that the plovers will return to from the south in the spring.

The tug's barge, the North Cape, went aground midway along a delicate necklace of eight saltwater beach ponds stretching from Narragansett to Westerly.

They are breeding grounds for fish and shellfish, refuge stops for millions of waterfowl that migrate along the Atlantic Flyway, and a major attraction for beachgoers and fishermen.

Majestic osprey also fish the ponds. Geese nest there, and ducks rest there on their fall and spring journeys.

The major ponds are Point Judith in Narragansett, home of the fishing fleet; Potter, Trustom, Cards and Green Hill in South Kingstown; Ninigret and Quonochontaug in Charlestown, and Winnapaug in Westerly.

Most of them are permanently breached to the sea, so that with each tide their water mixes with the ocean's.

This means that any oil in the sea can be sucked into the ponds -- endangering some of the most precious water resources in Rhode Island.

"It's horrifying; my heart is just sinking," said Virginia Lee, a URI oceanographer who has studied, roamed and fought to preserve the ponds for more than 15 years.

She said that while Trustom Pond has no permanent opening to the sea, it breaches naturally in some storms; a breach after an oil spill could mean the fouling of the wildlife preserve, she said.

Last night, the wind was blowing heavy, noxious fumes in the direction of Trustom.

Lee said the shallow coastal ponds, with an average depth of 3 feet, are especially valuable as spawning grounds for winter flounder -- actively sought by both commercial and recreational fishermen. In fact, she said, the ponds are thought to produce as much as 25 percent of the near-shore winter flounder fishery.

Luckily, she said, the spawning doesn't take place until March. But she feared what might happen then if oil "gets into the ponds and hangs around."

Fish larvae are especially sensitive to oil, Lee said.

She described the pond region as "a major gem of South County, and of Rhode Island tourism."

The ponds are already under pressure from development, she said, adding that an oil spill there would be "too horrifying to contemplate."