China is using its vast fishing fleet as the advance guard to press its expansive territorial claims in the South China Sea, experts say. That is not only putting Beijing on a collision course with its Asian neighbours but also introducing a degree of unpredictability that raises the risk of periodic crises.

In the past few weeks, tensions have flared with Indonesia, Malaysia and Vietnam as Chinese fishermen, often backed up by coast guard vessels, have ventured far from their homeland and close to other nations’ coasts. These are just the latest conflicts in China’s long-running battle to expand its fishing grounds and simultaneously exert its maritime dominance.

“The Chinese authorities consider fishermen and fishing vessels important tools in expanding China’s presence and the country’s claims in the disputed waters,” said Zhang Hongzhou, an expert at Singapore’s Nanyang Technological University.

“Fishermen are increasingly at the front line of the South China Sea disputes,” Zhang said, “and fishing incidents could trigger even bigger diplomatic and security tensions between China and regional countries.”