Researchers say the Dead Sea was a lively commercial center as far back as 2,300 years ago, not anywhere near like it is today with few boats and only sparse settlement along the shores.

The research may also throw new light on the Essenes who lived in the area, casting doubt on the accepted theory that they were isolated hermits.Arieh Nissenbaum, a geo-chemist, said three stone anchors and mooring ropes found recently in the Dead Sea were the "first datable evidence" to support the theory that the Dead Sea was an active place for commerce in the 4th century B.C.

He said Carbon 14 testing at the Weizmann Institute of Science in Rehovot on well-preserved fiber rope fragments left open the possibilty that the anchors were from ships sunk in the first Middle East oil war.

"The Dead Sea was not so dead. This is a misleading name given to the lake by the British," said Gideon Hadas, an Antiquities Authority archaeologist.

According to ancient historians, a huge naval battle was fought in 312 B.C. when Antigonus, the Seleucid ruler of Syria, tried to seize control of the trade in asphalt, which naturally forms from evaporating petroleum. He was repelled by the superior archery of the Nabateans of southern Jordan who were backed by Egypt.

Although there was uncertainty about the date because of a 100-year margin of error in dating, Nissenbaum said it is possible that "the anchors are mute witnesses to that battle."

Hadas found the 220-pound anchors along the western shore of the lake, which at 1,292 feet below sea level is the lowest spot on earth.

He said the ropes were well preserved because of the high salt content of the water and suggested other remains, even wooden boats, might also be nestling in the seabed.

Asphalt, which came to the surface in large blocks from fissures in the seabed, was the prize of ancient traders. Nissenbaum said it was used as mortar for buildings, an embalming agent in the Egyptians mummification process, a medicine to treat skin wounds and as a bug-killer.

In a new study of Dead Sea shipping, Nissenbaum said that up to the end of the Crusader era there was active boat traffic on the lake. Ships ferried wheat and corn grown in southern Jordan along the 50-mile length of the salt sea to the northern end where roads led to Jericho and Jerusalem.

A large Israelite farming community grew at Ein Gedi on the lake shore and Hasmonean kings built a series of fortresses in the area.

The Dead Sea region, surrounded by barren mountains and rocky desert, fell into economic decline after the Crusader period. Today the only boats on the lake are a few Israeli military patrol craft. Just a few small settlements occupy its shores, and foreign visitors come mostly to the health spas that promote the curative powers, especially for those afflicted with skin diseases, of the Dead Sea waters and mineral-rich mud.

Robert Eisenman, chairman of the religious studies department at California State University in Long Beach, suggests today's image of the Dead Sea as a lifeless region may be the basis of a misleading view of the Essenes, keepers of the Dead Sea scrolls.

Traditional theories about the sect portrays them as a small isolated community of hermits who sought refuge in a remote wilderness, but he suggests this may not have been the case.

His 15-member surveying and mapping expedition recently completed a study of the Qumran caves at the northern end of the Dead Sea. It was there that the scrolls dating to the second century B.C. were discovered in 1947.

Eisenman said his survey explored 282

desert caves along a 13-mile stretch of coast and found pottery as well as other evidence of man living in 62 of them. He said a 1952 survey found only 230 caves in the area and suggested man could live in only 17.

Eisenman added that his findings indicated there could be more scroll-bearing caves in the area and that many more had been

inhabitated than originally suggested.