ANCHORAGE, Alaska (AP) _ An American who was aboard a Japanese fishing vessel when it was seized by the Soviet Union has been released, the U.S. Coast Guard said today.

Mike Hilley, spokesman at the regional Coast Guard headquarters in Juneau, said Becky Kruppenbach was taken aboard the cutter Monroe at 8:03 a.m. AST. He said her personal gear also was transferred off the Fukunu Maru.

Contrary to earlier reports that the Japanese boat had been taken to a Siberian port, Hilley said the vessel was present along with a Soviet navy ship when the transfer was accomplished.

Hilley said Ms. Kruppenbach was in good shape and would be taken to Dutch Harbor, a voyage of about 10-15 hours.

The transfer took place in international waters 20-50 miles south of Cape Olyutorsky in Siberia, Hilley said.

Ms. Kruppenbach was aboard the Japanese vessel on behalf of the National Marine Fisheries Service to monitor compliance with catch quotas in U.S. territorial waters in the Bering Sea.

State Department spokesman Bernard Kalb said the Soviets have not said why the vessel was seized early Tuesday, but added it may have been in retaliation for Japan's seizure of a Soviet fishing boat on April 18. That vessel apparently still is being held by the Japanese, he said.

A Soviet official in Washington said it's unlikely the warship realized there was an American on board.

''It is my understanding, as far as I know, it was a military ice breaker and they didn't know how to communicate with a fishing vessel,'' said Yevgeniy Chaplin, first secretary of the Soviet embassy.

The waters where the Japanese boat was seized are claimed by both the United States and the Soviet Union.

Russ Nelson, a fishery biologist who supervises the NMFS observer program, said Ms. Kruppenbach was hired on a temporary basis through a contractor. It was her third voyage as an observer, he said.