The Coast Guard seized a Soviet fishing trawler 130 miles off Nantucket Saturday night for violating the new 200-mile U.S. fishing limit. The seizure, the first since the limit was imposed last month, came on orders of the White House and followed complaints from fishing states that the new limit was not being adequately enforced.

"We've released several of them [trawler], but we just had to draw the line somewhere," President Carter told reporters today after Easter services in Calhoun, Ga.

The 275-foot Taras Shevchenko is expected to arrive at the Coast Guard base in Boston Monday morning. A Coast Guard boarding party was directing the course from the trawler's bridge with the American flag flying overhead, a sign of the seizure.

Since March 28, five Soviet trawlers and a supply ship have been cited for fishing-limit violations, but all were ordered released despite Coast Guard recommendations that they be seized. "We informed the Soviet embassy that we could no longer continue to release them, that we had to enforce the law," Carter said today.

[A State Department source said the decisions on Russian trawlers "have always been made by the administration."]

[In the earlier incidents, the State Department advised the Coast Guard not to seize the trawlers "because that's what the administration said to do," the source said.]

[However, the source said the administration has now changed its mind.]

["There's no split between the administration and the State Department," the source said. "We're part of the administration. The administration is in charge of this thing."]

Under the Fishers Conservation and Management Act, which went into effect March 1, foreign vessels may fish within the 200-mile limit only in specified areas for specific fish and with special permits.

The Coast Guard, which makes spot checks, accused the Taras Shevchenko of catching and keeping more than its quota of river herring, which can legally make up only 1 per cent of the processed fish aboard.

Lt. Cmdr. Thomas Nunes, chief of the Maritime Law Enforcement Branch, said there were four tons of river herring, 1.2 per cent of the catch, aboard Saturday. According to the ship's log, he said, 16 tons of river herring, or 4.3 per cent of the catch, were unloaded from the trawler March 28, and 73.2 tons or 16.1 per cent, March 12.

"We have a gross violation here and we may find more as we go through the ship," he said.

James Gabriel, the U.S. attorney in Boston whose office is handling litigation in the case, said today he did not yet have enough information on the alleged violation to determine whether to press criminal or civil charges.

Maximum punishment for conviction on criminal charges is forfeiture of the ship, its catch and its equipment. Civil violations carry a fine of up to $25,000 for each violation.

The Soviet embassy officially refused comment on the seizure today. However, Yuri Znamenskiy, chief of the Soviet American Fishing Claims Service in Washington, said he will come to Boston Monday to speak with the trawler's captin "to see just what went wrong."

Znamenskiy added, "I would like to know exactly what happened, because our Ministry of Fisheries issued very, very strong orders not to go against any 200-mile limit."

The Soviet embassy was warned last Tuesday by Deputy Secretary of State Warren Christopher of the Carter administration's "great concern at the number of seriousness" of violations.

That warning came after criticism by New England politicians and fishermen of the release of foreign vessels that had been boarded and cited for violations, and allegations that the administration was downplaying the violations in order not to jeopardize U.S.-Soviet arms negotiations.

Rep. Gerry E. Studds (D-Mass.), whose 12th District includes the port of New Bedford, said today he believes the earlier recommendations for seizure were rejected "because someone in the National Security Council didn't know what the hell they were doing."

Studds contended last week that the rejections were based on policy laid down in a four-year-old NSC memorandum, which he asked be examined by the House Merchant Marine and Fisheries Committee. A closed session has been scheduled for April 21.

Meanwhile, a Coast Guard spokesman here said the 93-member crew of the Taras Shevchenko will be restricted to the vessel when it is in port. A security zone will be set up to keep small craft from approaching the vessel and the gangway will be guarded.

If the crew needs food or supplies, arrangements will be made through its agent, Kerr Steamship Co., of New York, or the Soviet embassy, according to Lt. Kent Fisher of the Coast Guard Atlantic Area Command in New York City.