Relentless vessel traffic threatens the GBA’s marine life

Map of the Guangdong-Hong Kong-Macau GBA: Orange polygons mark the boundaries of World Wildlife Fund and Hong Kong marine reserves and parks. Dotted blue lines indicate ferry routes and shipping lanes between ports

Analysis

The Greater Bay Area (GBA) is one of the world’s largest and fastest-growing coastal megaregions. The busy maritime hub is home to approximately 86 million people and is a powerhouse economy accounting for about 12% of China’s GDP.

Its ports, including Shenzhen, Guangzhou, Hong Kong, and Macau, rank among the busiest in the world, handling roughly 10% of global trade volume. However, this economic dynamism and intense vessel activity comes exerts significant pressure on coastal waters and wildlife.

New research reveals how persistent and dense marine traffic, especially from non-fishing vessels, is reshaping the region’s marine ecosystems and posing serious threats to vulnerable species and habitats.

A comprehensive six-year study (2013-2018) led by researchers from the University of Exeter and the Chinese University of Hong Kong mapped the daily movements of vessels in the GBA using satellite-derived Automatic Identification System (AIS) data.

The findings are stark: on average, 5,981 unique vessels operate daily in the area, with non-fishing vessels outnumbering fishing boats nearly tenfold. Most vessel traffic—about 80%—occurs in shallow waters less than 20 meters deep, which are critical habitats for many marine species.

The persistent presence of vessels in shallow zones increases shoreline erosion, stirs up sediment causing turbidity, generates underwater noise pollution, and raises the risk of collisions with marine animals.

The report cites some conservation hotspots experience vessel disturbance on more than 95% of days, leaving little refuge for marine life. “The shallow water also means species cannot escape into the depths, leaving them little refuge,” said University of Exeter’s Dr Phil Doherty.

Species of conservation affected include the Chinese white dolphin, finless porpoise, green turtles, and horseshoe crabs.

Fishing vs. Non-fishing vessel activity

While fishing vessels activity takes place in known fishing grounds and routes connecting ports; non-fishing vessels—cargo ships, tankers, passenger ferries, and high-speed crafts—dominate shipping lanes and transport corridors.

Non-fishing vessels are responsible for eight times more daily disturbances than fishing boats, reflecting their heavier traffic and larger spatial footprint.

Seasonal patterns from the study show fishing vessel activity dips during the Chinese New Year and “summer fishing moratorium”. Meanwhile non-fishing vessel numbers fluctuate around global and national holidays.

Despite some local decreases in vessel activity at the mouth of the Pearl River Estuary, overall maritime traffic has increased in other parts of the bay, particularly along shipping fairways and near urban centers.

“The pressure on marine environments near coastal cities is only increasing and we need to think about how to limit human impact,” states Dr Stephen lang from the University of Exeter.

Ecological hotspots under pressure and ongoing efforts

The study highlights that marine protected areas, ecological hotspots, and core habitats for species like the Chinese white dolphin are heavily trafficked.

Daily vessel occupancy in some marine parks and reserves reaches up to 82%, with ecological hotspots showing variable but often significant vessel presence.

This overlap complicates conservation efforts and threatens the integrity of these sensitive areas.

Efforts to balance economic growth with environmental sustainability are underway. China has implemented measures such as reducing fishing fleet size and enforcing summer fishing moratoriums to mitigate fishing impacts.

Dr Felix Leung, from the Chinese University of Hong Kong, said “to safeguard these ecologically sensitive areas, governments must adhere to the Global Biodiversity Framework, ensuring both protection and sustainable management for future generations.”

Innovative marine technologies, including coral planting and marine exhibitions, are being explored to promote sustainable tourism and enhance marine ecosystem resilience in the GBA. By Nadia Shaw, MDT