Mexican police have arrested Jaime Herrera, the head of a notorious Mexican-American smuggling family regarded as the chief distributor of heroin from Mexico to the United States, authorities announced yesterday.

After hunting Herrera for almost a year, Mexican narcotics agents finally tracked him down and arrested him in Guadalajara on Tuesday, the Mexican Federal Police said.

By grabbing Herrera, U.S. and Mexican narcotics officials feel they will be able to crack a vast and sophisticated drug network that they believe is responsible for bringing to the United States 3,000 pounds of heroin a year, more than a quarter of the total available across the country.

[In Washington officials of the Drug Enforcement Administration praised the work of Mexican authorities. They said the Herrera ring's activities sent about $100 million a year back to Mexico and generated "several times that" in retailers' profits in American cities.]

[David Westrate, executive assistant to DEA chief Peter Bensinger, said U.S authorities could not be sure Herrera would not simply be replaced by another member of the group. But he said it was hoped the arrest would "disrupt the organization because of the loss of leadership."]

The Herrera network is believed to involve close to 1,000 persons, including family members, associates and friends on both sides of the border.

American narcotics agents have known about the operation for about four years. Herrera's arrest warrant was issued in Mexico late last year for "possession, supply and processing of heroin."

According to agents close to the case, 57 indictments are pending in the United States against members of the Herrera family.

Under extremely strict security arrangements, Herrera was taken yesterday to Durango, the capital of the nothern state of Durango, where agents say the Mexican branch of the family had its base.

The family began to grow opium poppies about 25 years ago in Durango's uninhabited Sierra Madre Occidental, which proved to be a perfect spot for harvesting the opium, transporting the gum and processing it into heroin in safe houses. Opium had come to Mexico several decades earlier with the arrival of Chinese railroad builders on the West Coast.

The Herreras started off as a small family business, dealing in limited quantities within the security and trust of a family affair. Mexican police say they could never prove it, but they believe that early on the Herreras started financing small farmers to grow their opium crops for them.

Then the Herreras branched off into setting up their own laboratories for processing the gum and began to move the powder into the United States. The police say. At first it was only sent to Chicago, where other members of the family set up shop, they say.

In recent times, the operation was said to supply 60 percent of the total heroin supply in the Chicago area. Between 60 and 70 percent of all heroin supplied to U.S. addicts comes from Mexico, according to U.S. narcotics agents.

In recent years, as the Turkish-French connection started drying up and at the same time the number of heroin users in the United States increased, the Herrera operation grew dramatically.

"The formula for their success and their long survival has been that they have a higher degree of discipline than most organizations," said an experienced U.S. agent. "They learned on the job, grew slowly, stayed close-knit. They are very hard to penetrate. Anyone new had to be voted for and watched by people on the inside."

Another secret of their success has been the ingenuity with which they smuggled the heroin from Mexico into the United States most of it going overland, almost invariably by car. "They've not only been good about their hiding places, but they took little risk. Because they're big they wouldn't worry about losing a load, the U.S. agent said.

The tracking down of the Herrera connection was a joint U.S.-Mexican operation with the U.S. Drug Enforcement Agency turning over its files to Mexican authorities.