Mexico Backs Away From Pact on Tuna : Trade: The deal to protect dolphins had been struck earlier this year. Some see the latest action as an effort to gain a NAFTA bargaining chip.

Mexico’s Foreign Ministry has rejected an agreement reached earlier this year with the U.S. government that would have banned tuna fishing in a part of the Pacific Ocean where thousands of dolphins are killed each year.

In February, the United States and the presidents of Mexico and Venezuela agreed to a five-year moratorium on dolphin-endangering tuna-fishing methods in the eastern tropical Pacific. In exchange, the U.S. government agreed to lift its current ban on tuna imports from those countries.

But Mexico now says that the International Dolphin Conservation Act of 1992, signed into law by President Bush last month, will severely damage the nation’s tuna-fishing industry and cause heavy job losses.

Mexican officials say that changes made in the agreement when the U.S. Congress translated it into federal law have made the moratorium unacceptable.

A State Department spokesman had no comment Tuesday, saying that the United States has not been notified of the Mexican ministry’s decision.

U.S. and Mexican environmentalists and political observers said Tuesday that the rejection might give Mexico a bargaining chip in negotiations over an environmental treaty that accompanies the North American Free Trade Agreement among the United States, Canada and Mexico.

Mexico has the largest tuna-fishing fleet in the eastern tropical Pacific, a part of the world where tuna and dolphin swim together and dolphins are often caught and killed in purse-seine nets.

“Even though the new legislation raises the possibility of lifting the embargo on Mexican tuna,” the Mexican Foreign Ministry said in a statement, “the consequences of the moratorium under the terms provided for in the law would be graver than the embargo currently in effect, in that it would cause a drastic reduction in the production of the Mexican tuna fleet, the loss of jobs and the reduction of the supply of fish products for domestic consumption.”

Environmentalists note that Mexican fisheries officials have opposed a moratorium all along. But the U.S. State Department assured Congress during hearings last summer that Mexican President Carlos Salinas de Gortari intended to abide by a moratorium.

Many observers in the United States and in Mexico said the rejection may have anticipated a victory by Arkansas Gov. Bill Clinton in Tuesday’s presidential election. Clinton has said he would sign NAFTA only if its environmental provisions are modified.

“This could be a NAFTA bargaining chip,” said David Phillips, executive director of Earth Island Institute, a San Francisco-based environmental group.