China has once again announced a unilateral fishing moratorium in the South China Sea, which drew vigorous protests by Vietnam while the Philippines has so far not reacted.

The 3½-month ban began Sunday and covers waters north of 12 degrees north latitude in the South China Sea which Vietnam and the Philippines also call their “traditional fishing grounds.”

Hanoi spoke out against the fishing ban, calling it “a violation of Vietnam’s sovereignty and territorial jurisdiction.”

The moratorium applies to part of the Gulf of Tonkin and the Paracel islands claimed by both China and Vietnam.

“Vietnam requests China to respect Vietnam’s sovereignty over the Paracel islands, sovereign rights and jurisdiction over its maritime zones when taking measures to conserve biological resources in the East Sea [South China Sea], without complicating the situation toward maintaining peace, stability and order in the East Sea,” said Le Thi Thu Hang, the Vietnamese Foreign Ministry spokeswoman.

She said Vietnam’s stance on China’s fishing ban “is consistent and well established over the years.”

Meanwhile the Philippines, which holds a presidential election on May 9, had not responded to the moratorium.

In the past, Manila repeatedly protested and even called on Filipino fishermen to ignore the Chinese ban and continue activities in the waters also known as the West Philippine Sea.

China has imposed the annual summer fishing ban since 1999 “as part of the country’s efforts to promote sustainable marine fishery development and improve marine ecology,” Chinese news agency Xinhua reported.

A collapse of fishery stocks in the South China Sea because of overfishing and climate change could fuel serious tensions and even armed conflict, analysts have said.