China plans to impose underwater denial zone to obstruct submarine activity

China is planning to impose an "underwater denial zone" to obstruct submarine activity in the Taiwan strait area, reported Taipei Times.

Taiwan should improve maritime surveillance to boost its defence, assist its marine economy and lend support to like-minded allies as China might be planning to impose an "underwater denial zone" to stymie submarine activity, said a military expert.

Institute of National Defense and Security Research fellow Su Tzu-yun said that Taiwan had not invested enough into surveying its surrounding waters, reported Taipei Times.

He added that if the nation improves its maritime surveillance capabilities, it could also assist strategic cooperation with like-minded partners.

In the eight days between April 16 and Sunday, the Ministry of National Defense detected five incursions by Chinese People's Liberation Army (PLA) Harbin Z-9 anti-submarine helicopters east and southeast of the nation's air defence identification zone.

On Sunday, Monday and Wednesday last week, they were found southeast of the nation, then on Saturday and Sunday operated further north above the waters east of Hualien County, reported Taipei Times.

The Harbin Z-9 might have been operated by a Type 054A frigate stationed nearby, the main anti-submarine ship in the PLA fleet.

Unlike the shallow basins to the nation's west and southwest, the oceanic terrain off the east coast is complex, composed of ridges, trenches and basins, Su said, adding that the area has therefore become a hotspot for surveillance conducted by PLA anti-submarine aircraft, reported Taipei Times.

The information found on these missions would be valuable for PLA submarines to predict the movements of Taiwanese submarines, he said.

Asked why the PLA has been ramping up helicopter activity, Su said it might be related to naval training, as sea conditions are optimal in mid-to-late April, reported Taipei Times.

It could also be an acceleration of operations east of Taiwan, as the PLA might be aiming to turn the waters to the east and southwest into "underwater denial zones," he said.

The experience of the operating frigates could also be used as a reference for larger amphibious ships in advance assessments for transport and attack helicopter missions, he said.

The data could be useful not just for military purposes, but also for the marine economy and fishing industry.