To this end, China has contentiously drawn the so-called “Nine Dash Line”, a large tongue-shaped area extending considerably beyond the 200-mile limit, in which it claims historical sovereignty over more than 90% of the South China Sea, including many of its reefs and islands. This has brought China into direct conflict with a number of its neighbouring states in this region, with the Philippines, Vietnam, Malaysia, Brunei and Taiwan also laying claim to these waters.

One of the most significant – and increasingly bitter – international disputes of recent years has engaged legal claims over maritime territory in the South China Sea. Under the United Nations Convention on the Law of the Sea of 1982 (UNCLOS), to which the main protagonists are parties, states are entitled to claim an Exclusive Economic Zone (EEZ) conferring sovereign rights and jurisdiction up to 200 nautical miles of maritime space from their coasts. In the South China Sea, however, this position has been complicated by historical claims over a series of small islands and reefs within the southern section of this area.

Meanwhile, widespread environmental concerns have been raised by an extensive programme of land reclamation conducted by China within the sensitive marine ecosystem of the South China Sea, building a series of larger islands around a series of reefs with the intention of reinforcing ownership of these areas and generating additional EEZs around a number of the resulting “islands”. Wider security controls have been raised by an increasing degree of Chinese militarisation of these waters, as well as allegations of intimidation of Filipino fishermen seeking to exercise traditional fishing rights.

Against this increasingly complicated backdrop, in 2013 the Philippines initiated a process of arbitration against China, seeking clarification of the legal entitlements of both states within the South China Sea, as well as a ruling as to whether the contested rocks and reefs could qualify legally as “islands”. On Tuesday, in a highly extensive award, an international tribunal in The Hague ruled in favour of the Philippines, rejecting China’s claim of historical title over these waters and finding that many of the terrestrial features within the disputed area failed to meet the legal definition of an island. Moreover, the panel ruled that China had unlawfully prevented the exercise of traditional fishing rights in particular locations, while also conducting fishing within areas under Filipino jurisdiction without permission. The tribunal also held that Chinese fishermen had harvested endangered species, such as sea turtles, coral, and giant clams, on a “significant scale” and, with the toleration of the Chinese authorities, had conducted activities that were highly destructive to the coral reef ecosystem. Perhaps most significantly, however, the panel further considered that China had breached its obligations concerning the marine environment under UNCLOS in conducting unauthorised land reclamation projects around many of the reefs and islands, which it declared to have caused “severe, irreparable harm” to the ecosystem.

The value of the South China Sea

The South China Sea is a relatively small area of the world’s oceans, at 3.8 million square kilometers, but it has great economic and ecological significance. The area is bordered by 12 countries and territories and is home to two billion people, incorporating some of the world’s fastest growing economies. It is also one of the five most productive fishing zones in the world, providing some 12% of the global fishing catch.

The South China Sea is biologically diverse, providing habitat for at least 3,365 known species of marine fishes. Given its richness in resources and biodiversity and its strategic location, the sea is a crucial element for coastal livelihoods and local economies. At least 3.7 million people are estimated to be employed in the fishing industry in this area, though the true figure is likely to be considerably larger given the high rates of small scale and unreported fishing. In addition, a recent studyhas indicated that many countries bordering the South China Sea are amongst those most reliant on fish as a food source and, thereby, vulnerable to micronutrient malnutrition.

The state of fisheries and marine ecosystems in the region

A 2015 report by OceanCanada Director Rashid Sumaila and Nereus Director of Science William Cheung, “Boom or bust: The future of fish in the South China Sea”, found that overfishing and habitat destruction has become a substantial problem in this region, with species fished to 5-30% of their levels in the 1950s. The use of intensive commercial trawl fishing for a number of decades — the pulling of nets behind boats resulting in catches of a variety of species — combined with an intensification of fishing effort over the past thirty years has led to the overexploitation of these fisheries. Other destructive fishing practices have included the use of dynamite and cyanide on reefs, conduct that was condemned by the arbitral panel. As a result of these activities, the coral reefs of the South China Sea have been declining at a rate of 16% per decade. The wider ecosystem has also suffered the effects of pollution from agriculture and coastal development. In addition, marine biodiversity and fisheries in the region are acutely vulnerable to the adverse impacts of climate change and ocean acidification.

The report’s authors found that by 2045, under a “business as usual” scenario for fishing and climate change, each of the species groups studied would decrease by 9 to 59%. Of greatest concern, those more vulnerable to the impacts of fishing, such as groupers, large sharks, threadfin breams, and large croakers were projected to decline by 50% or more. The authors found that only a 50-60% reduction in fishing effort would allow the beleaguered stocks of the South China Sea to recover.