The trawler was stopped July 1 by Russian coast guards on suspicion of poaching, and was found to have illegally caught and processed over 15 metric tons of red salmon instead of the cheaper Keta salmon.
The court also ordered the vessel's owner pay 7.9 million rubles ($309,000) compensation to local authorities.
The Law of the Sea tribunal in Germany ruled August 6 that Russia should return the trawler, and reduced a fine imposed by Russia from 22 to 13 million rubles (around $500,000). On August 16, the Hoshin Maru-88 returned to Japan.
Russian authorities have been involved in several disputes in recent years over fishing rights in its Pacific waters, particularly with Japanese vessels.
In August 2006, the captain of a Japanese ship was detained near the Kuril Islands off Russia's Pacific Coast in an incident where one of his crewmates was shot and killed by Russian coast guards.
