The security implications of these disputes receive significant attention, and the disputants’ navies, air forces, and coast guards are studied closely to assess the balance of power and risk of escalation. But too little attention has focused on another key set of actors in the South China Sea—the fishers who serve on the frontlines of this contest. Those fishers face a dire threat to their livelihoods and food security as the South China Sea fisheries teeter on the brink of collapse.
The South China Sea accounted for 12 percent of global fish catch in 2015, and more than half of the fishing vessels in the world are estimated to operate there. Its fisheries officially employ around 3.7 million people and unofficially many more. But the South China Sea has been dangerously overfished. Total stocks have been depleted by 70-95 percent since the 1950s, and catch rates have declined by 66-75 percent over the last 20 years.
Coral reefs, on which much of these fish depend, have been declining by 16 percent per decade. And that decline rapidly accelerated over the last five years in which giant clam harvesting, dredging, and artificial island building have severely damaged or destroyed over 40,000 acres, or about 160 square kilometers, of reefs.
As they race to pull the last fish from the South China Sea, fishers stand at least as much chance of triggering a violent clash as do the region’s armed forces. And that has become even more likely as a significant number of fishing vessels in the area forgo fishing full-time to serve as a direct arm of the state through official maritime militia.
To provide a clearer picture of the size and activities of these important players, CSIS undertook a six-month-long project in cooperation with Vulcan’s Skylight Maritime Initiative to leverage previously underused technologies and data sources to analyze the size and behavior of fishing fleets in the most hotly-contested part of the South China Sea, the Spratly Islands.
The results tell a worrying story about the scale of unseen fishing activity in the region, massive overcapacity in the Spratlys, especially on the Chinese side, and the stunning scale and expense of the maritime militia.
Tracking the Boats
Conducting accurate stock assessments and managing fisheries in the South China Sea is all but impossible because of the overlapping territorial and maritime disputes, which prevent effective enforcement of domestic fishery laws or cooperation among regional states. In fact, some states actively encourage and even subsidize fishing in disputed waters to assert their claims.
Attempting to monitor fishing activity remotely is uniquely difficult in the South China Sea. But several different technologies—AIS, VIIRS, SAR, and optical satellite imagery—can be combined to monitor this activity.
Automatic Identification System (AIS)
For a region where so much fishing is reported, boats are surprisingly difficult to identify in the South China Sea. The Spratly Islands, in particular, are devoid of Automatic Identification System (AIS) signals. The absence of signals is due in large part to the small size and age of many fishing vessels, especially in the Philippines and Vietnam. But many vessels operating in the Spratlys have transceivers and should be using them but choose not to so that they can hide their activities. This necessitates turning to other technologies for a clearer picture of the size and activities of fishing fleets in the South China Sea.
Visible Infrared Imaging Radiometer Suite (VIIRS)
One of the most helpful sources of data on fishing in the South China Sea, and around the world, is the Visible Infrared Imaging Radiometer Suite (VIIRS) Boat Detection product, which can detect bright light sources at sea. It reveals a huge amount of fishing activity takes place in the South China Sea, including in and around the Spratly Islands, despite its invisibility in the AIS record.
VIIRS data shows a significant amount of fishing in the South China Sea year-round, with the most active months being March through June. Within the Spratlys, the peak fishing season is March-April. There is also an increase in activity along the coasts of China and Vietnam in August, coinciding with the end of a unilateral three-month fishing ban that Beijing imposes each year in the northern portion of the South China Sea. But most importantly, VIIRS shows that the overall level of activity, regardless of season, has been steadily increasing year to year.
Synthetic Aperture Radar (SAR)
For a more granular analysis, Synthetic Aperture Radar (SAR) provides an approximate count of vessels at a given time and location. Anything metallic, like the hull and superstructure of most modern fishing vessels as small as six meters, can be readily identified by satellite-based SAR. Again, the disconnect between the level of activity and the number of AIS signals being broadcast was staggering. For instance, SAR data collected on eight occasions between September 30 and October 5 provided 264 vessel detections, only 8 of which were broadcasting AIS.