Chinese sailing vessels have behaved with increasing aggression toward two U.S. ocean surveillance ships operating in the Yellow and South China seas. Though this recent behavior is not unprecedented, the U.S. 7th Fleet is characterizing it as a departure from normal interactions and the most aggressive behavior the fleet has seen from China in a long time. These aggressive moves might herald things to come as the maritime environment around China becomes increasingly active — and crowded. On March 4, the USNS Victorious (T-AGOS 19) had an encounter at night with a Chinese Bureau of Fisheries patrol vessel in the Yellow Sea. The USNS Impeccable (T-AGOS 23) was approached more aggressively in the South China Sea the next day, when a Chinese People's Liberation Army-Navy (PLAN) frigate reportedly crossed the Impeccable's bow at a range of about 100 yards, and the Impeccable was buzzed nearly a dozen times at low altitude by a Y-12, a Chinese-made twin-engine turbo prop. Reportedly, the ship was threatened verbally over bridge-to-bridge radio on March 7 as well. But it was the March 8 incident with the Impeccable that garnered the most attention. According to reports, a PLAN intelligence collection ship, a Bureau of Maritime Fisheries patrol vessel, a State Oceanographic Administration patrol vessel and two small Chinese-flagged trawlers were all involved in what the U.S. Navy has characterized as coordinated harassment of the Impeccable. Some of the ships were within 25 feet of the Impeccable at one point and stopped in front of the U.S. ship so close that the crew executed an emergency all stop to avoid a collision. (click image to enlarge) The Impeccable is an ocean surveillance ship, part of the Military Sealift Command, and is operated by a mixed crew of civilian and military personnel. Capable of deploying towed acoustic arrays, the U.S. ship was operating within 75 miles of Hainan Island, where a number of sensitive PLAN and other military activities are conducted (reportedly including the deployment of the PLAN's next-generation nuclear-powered attack and ballistic missile submarines). China would at least be concerned about the United States refining its knowledge of the submarine operating environment, and likely felt compelled to assume that the Impeccable was conducting other surveillance and intelligence-gathering activities. This is not a new dynamic. It is the same basic dynamic that gave rise to the EP-3 Ares II incident in 2001, in which a Chinese aircraft collided with a U.S. signals intelligence aircraft, forcing the EP-3 to land at Hainan Island. Normally, these activities are routine, and both sides abide by internationally accepted or even unspoken sets of rules. But when one side chooses to escalate the situation, matters can quickly spiral out of control. Part of this is simply a matter of increased PLAN activity, characteristic of a larger shift in how Beijing employs its navy. But with the PLAN's 60th anniversary approaching in April (a formal announcement about its plans for an aircraft carrier fleet is anticipated), and the impending return of its first squadron deployed to the coast of Somalia, the Chinese navy is undoubtedly feeling rather confident and accomplished these days. But internal tensions may also be at play. With the financial crisis in full swing, the PLAN may also be attempting to drum up incidents for budgetary purposes, to forestall major fiscal cuts to its accounts. More importantly, the March 8 incident is emblematic of broader maritime tensions in the East Asian sphere — and not just between China and the United States. Over the past several months, tensions over long-standing maritime territorial disputes have once again risen across the region. North Korea has once again declared that it does not abide by the Northern Limit Line, the maritime extension of the Demilitarized Zone in the West/Yellow Sea, warning that a clash with South Korean naval vessels patrolling the area could occur. Japan, meanwhile, has launched a 10-year seabed mapping and underwater resource prospecting program, triggering warnings from Seoul and Beijing not to use the operations to lay claim to the disputed Tokdo/Takeshima and Senkaku/Daioyutai islands respectively. And China's competing claims over islands in the South China Sea are also resurfacing, provoking counterclaims from the Philippines, Malaysia and Vietnam. In short, the waters around China are becoming more crowded and the mood increasingly contentious. The March 8 incident could herald increased volatility in the maritime environment — across the region — for years to come.