FRANCE is trying to win back some of the riches it lost on the Plains of Abraham, the battle in which Gen. James Wolfe took New France for Britain in 1759.At stake are fishing rights in the Grand Banks, the richest fishing grounds in the North Atlantic, and the Hibernia Oil field off the coast of Newfoundland. The Hibernia Oil field is the site of major oil and gas discoveries; offshore rigs such as those in the North Sea are now drilling within Canada's 200-mile territorial limit. The argument is over the size of the territorial limit around the tiny islands of St. Pierre and Miquelon 12 miles off the southern coast of Newfoundland. The fishing outposts were given to France in 1763 as a consolation prize after it ceded New France to England. France now wants a 200-mile limit around the islands, granting it almost 20,000 square miles; Canada wants it limited to 12 miles, for an area of about 1,400 square miles. The case is before an international tribunal in New York City and the issue will be decided late this year or early in 1992. The argument surfaced when Canada first declared its 200-mile zone in 1977 to protect its eastern fishing waters. Ever since, France has said it wants the same. Taking the issue to an international tribunal is a big gamble; the winner takes all. France and Canada have agreed to accept the decision and not appeal. The opening salvos were fired by each side in the last week of July. The case rests on geography" Canada's minister of justice, Kim Campbell, told the hearing. "A glance at the map tells us that the islands of St. Pierre and Miquelon lie very close to Canada and very far from France," she said. Irrelevant, said her opponent, France's minister of justice, Henri Nallet. "St. Pierre-Miquelon is France, and the distance separating it from Paris is irrelevant," said Mr. Nallet. He argues that as a piece of France the islands deserve a 200-mile limit. St. Pierre and Miquelon are run as a French department, and have nothing to do with Quebec or French-Canada. At the post office, the stamps are the same ones on sale in Paris. The 6,000 residents send two deputies to the French legislature. Canada says if France is granted the fishing zone it will ruin Canada's offshore fishing. "For the 80,000 people on the south coast of Newfoundland," said Mrs. Campbell, "it is a matter of devastation or survival." A Canadian historian says France doesn't have any solid legal arguments, but it has a lot of gall. "The French are taking a gamble to see how much they can get away with," says Robert Bothwell, a professor of Canadian History at the University of Toronto. "Win or lose they can use this as a bargaining chip in negotiating fishing rights with Canada. And now ... there is oil and gas under the water as well as the fish." Campbell said the French claim endangered North American security by giving France control of such a huge area of the Gulf of St. Lawrence, which could bar access to the St. Lawrence Seaway, the Great Lakes and both American and Canadian inland ports. Campbell said the British didn't have this in mind when they gave the islands to France in the 18th century. "The islands were not meant to serve as a kind of Trojan horse out of which French claims of aggrandizement might come spilling forth."