Why MExico threw its US fishing accords overboard

Mexico's decision to terminate a variety of fishing accords with the United States results from: * A continuing MExican pique with the Carter administration over Washington's refusal to give MExican fishermen a share of the squid and other fishing catches off the New England coast.

* The inability of the two nations to reach agreement on tuna fishing off the Mexican coast. This recently led Washington to impose an embargo on Mexican tuna imports after Mexico seized US fishermen.

* A conscious Mexican desire for a st rong bargaining position when Mexican President Jose Lopez Portillo sits down with President-elect Ronald Reagan Jan. 5 in their first face-to-face session.

The Mexican government wants Mr. Reagan to realize that the days of US domination of Mexico are over. "The Lopez Portillo-Reagan meeting will be a meeting of equals," said a Mexican government spokesman Dec. 28. "We share a 2, 000-mile frontier and the people on each side of the border merit equal respect."

For months, the Lopez Portillo government quietly has been trying to win a US quota for Mexican fishermen to catch squid off the northeast coast of the US. In the view of Mexican officials, "Washington ignored our pleas." US officials counter that the matter remains under study.

But in the MExican view the Carter administration is simply dragging its feet on the squid issue and on Mexican efforts to work out a tuna accord with the US. The Mexicans put much of the blame directly on Mr. Carter.

Relations between Presidents Lopez Portillo and Carter have deteriorated sharply over the past three years, and the Carter administration now has little leverage with the Mexicans.

This legacy of ill will between Mexico and the US will be inherited by the incoming Reagan administration. It is also, however, an opportunity for new beginnings -- and that helps explain Mr. Reagan's decision to meet with Mr. Lopez Portillo Jan. 5. Although the two have met before and reportedly got along well, each will be taking a measure of the other during the session.

The meeting in the Mexican border town of Ciudad Juarez, across the Rio Grande from El Paso, Texas, was originally seen as little more than a symbolic occasion. But with the longstanding fishing dispute mushrooming into a major issue and concern growing in the US over the illegal or undocumented worker situation, the session takes on new meaning.

The MExican decision to end its various fishing accords with the US, which govern US fishing for grouper and snapper in the Gulf of Mexico, was designed in part as a bargaining chip in future Mexican-US fishing talks.

As seen in Mexico City, there is need for a broad-ranging fishing accord between the two nations, covering everything from tuna to snapper, grouper to squid, imports to exports. Lurking in the background of the whole imbroglio are Mexican worries about having enough foodstuffs to feed its burgeoning population. Efforts to get more fish products into the Mexican diet have recently been started.

The fishing rights controversy came to the surface last July when Washington slapped an embargo on Mexican tuna imports in response to the seizure of six San Diego-based tuna boats caught fishing in Mexican waters in violation of Mexican territoriality.

The dispute has simmered ever since. Mexican officials say they warned the Carter administration in November that progress on at least some aspects of the dispute would have to be made quickly or the Mexicans would take matters into their own hands. That warning went unheeded, say the Mexicans, and set the stage for their decision to cancel the Gulf of Mexico and Pacific Coast accords. Staff writer Clayton Jones reports from Boston:

A quickening need for US food by Mexico has helped escalate a battle for protein from the sea.

Mexican President Lopez Portillo's goal of food self-sufficiency for his country, set last year in a fishing and agricultural initiative known as the Global Development plan, has yet to keep pace with rising consumer demand. As a result, US food exports to its third-largest trading partner have doubled in the past year -- up to $2 billion -- and are expected to go even higher.

"Mexico, for the first time in its history, has leapt into major US food imports, like the Soviet Union and China," says Alfredo barrassing, food dependency has increased pressure to expand its fishing fleet -- including the wooing of US tuna boats to fly under the Mexican flag (five converted this year).