The Diet passed bills Wednesday to strengthen penalties for poaching in the nation's territorial waters and exclusive economic zones, following a recent surge in coral poaching by Chinese vessels in Japanese waters.

The revisions in fisheries regulations raise the fine for poaching in Japanese territorial waters (up to 12 nautical miles from the coast) from ¥4 million to ¥30 million, and that for unauthorized fishing within its EEZ (up to 200 nautical miles from the shoreline) from ¥10 million to ¥30 million.

The penalty for foreign ships found in the nation's territorial waters or EEZ that refuse inspections by the authorities has also been raised, to ¥3 million from ¥300,000.

More than 200 foreign vessels, suspected to have come from China, were observed poaching red coral, highly prized in China for jewelry, in waters around the Ogasawara and Izu islands off Tokyo earlier in the month, prompting the government to bolster surveillance by dispatching patrol boats, planes and police officers to the area.