SEOUL, South Korea - South Korea's coast guard dispatched dozens of ships yesterday to try to contain 2.7 million gallons of oil from a supertanker spill and keep it from reaching an ecologically sensitive shoreline on the country's west coast.

Strong winds and currents early today threatened to carry the oil slick toward fishing grounds and fish farms along the shore, the Coast Guard said in a statement.

Crude oil gushed from a 146,000-ton Hong Kong-registered tanker after a Samsung Corp. vessel slammed into it. The spill was believed to be South Korea's largest, according to the coast guard and Maritime and Fisheries Ministry.

There were no casualties in the accident, the coast guard said.

Maritime authorities set up a five-mile fence to try to contain the oil slick, which measured 4.6 miles long and 1.2 miles wide, officials said. The coast guard said 46 ships, including navy and other government vessels, plus four helicopters, were involved in the cleanup operation.

The accident occurred near Mallipo beach, about 90 miles southwest of Seoul. The area is known for scenic beaches and is home to a national maritime park and an important rest stop for migrating birds.

Chang Geun-ho, a ministry official, said the extent of environmental damage would depend on the success of the containment operation, though he added that cold winter temperatures could help slow the spread of the oil slick by freezing it.

The size of the leak reported by the authorities was about one-fourth that of the 1989 Exxon Valdez spill that leaked 11 million gallons of oil into Alaska's Prince William Sound.