In late summer each year, Beijing lifts its annual ban on fishing in the East China Sea and hundreds of Chinese vessels join their counterparts from Taiwan and Japan for the start of fishing season in those waters. Between August 5 and 9, 2016, just days after the end of last year’s ban, 200-300 Chinese fishing boats accompanied by 16 China Coast Guard (CCG) vessels arrived in the waters near the disputed Senkaku Islands. Many of them repeatedly entered the 12-nautical-mile territorial sea around the islets. The flotilla, which appeared to be endorsed if not directly organized by Chinese authorities, caused a tense standoff with the Japan Coast Guard.

East China Sea watchers spent this summer worried about a repeat of such tensions when the fishing ban ended again on August 1. Fortunately, there were no reports of major incidents between fishing crews and regional law enforcement vessels around the Senkakus in the late summer and fall. And data collected by AMTI lends credence to the idea that fishing vessels have been much less provocative in their operations around the islets—so much so that it might indicate a purposeful effort by the government in China to constrain its fishing fleet and avoid escalating tensions.

AMTI tracked the paths of 380 fishing vessels flagged to China, Japan, Taiwan, or of unknown nationality near the Senkakus from July 31 to October 18 using Automatic Identification System (AIS) data provided by Windward, a maritime data analytics company. This method cannot track small ships that are not required to carry AIS transceivers, or those vessels that purposely disable or tamper with their systems. In addition, AIS signals, particularly from older and less powerful transceivers, are often lost in high-traffic areas and remote waters where satellites rather than ground-based stations provide the only method of collection. Nonetheless, these 380 ships accounted for about 8,700 AIS transmissions (including about 4,600 signals from Chinese-flagged ships) and paint a good picture of the overall state of play around the Senkakus.

From August to October, fishing boats from China and Taiwan didn’t just stay out of the 12-nautical-mile territorial sea around the Senkakus—they overwhelmingly avoided entering the 24-nautical-mile contiguous zone. Japan is highly sensitive about foreign activity within this zone, over which the UN Convention on the Law of the Sea only grants states limited policing rights for things like customs and immigration violations. For most purposes, the area within the contiguous zone is legally indistinguishable from the area outside it. The fact that so much fishing activity during this period was clustered around the edges of the contiguous zone might therefore indicate a government effort, especially by China, to dissuade vessels fishing under the Chinese flag from provoking the Japanese authorities.

Furthermore, of all the fishing ships monitored around the Senkakus during this period, only three entered the territorial sea around the islets. All three of those were Taiwanese and, based on their paths, it is plausible that they were only transiting and did not engage in any fishing activity while in those waters.

CCG activity around the Senkakus for the last several months tells much the same story. After spiking last August during the fishing flotilla incident, the size and frequency of patrols around the islets settled into a new, albeit slightly elevated, normal. Most months this year saw 10 or 12 CCG vessels enter the territorial sea of the Senkakus—up from the earlier status quo of 8 to 10 per month that prevailed from late 2014 until August 2016. Just four CCG ships entered the territorial sea in October and seven in November 2017, but it remains unclear whether those were anomalous or indicate a more sustained reduction.

With China holding the 19th Party Congress and Japan organizing a snap election in late October, an incident around the Senkakus could have introduced unwelcome and difficult to control dynamics at a politically sensitive time for both countries. Instead, Beijing and Tokyo seemed intent on advancing a tentative rapprochement. Prime Minister Shinzo Abe of Japan even hailed a “fresh start” in the China-Japan relationship after meeting with China’s President Xi Jinping on the sidelines of the Asia Pacific Economic Cooperation summit in Vietnam in November. With the underlying claims unchanged, and both sides determined to continue their activities around the islands, tensions around the Senkakus are likely to spike again. But recent months have shown that China is capable of constraining its fishing fleet in the East China Sea.