The pressure being put on marine environments near coastal cities is mounting at a startling rate with the development of megacities such as China’s Greater Bay Area exposing ocean wildlife and habitats to ‘relentless’ boat traffic and an average of 6,000 vessels moving through its waters each day.

Concern has been raised among researchers behind a new study that with this level of marine traffic moving through their habitats on as much as 95% of days in the year, “little undisturbed space is being left for nature.”

It’s across China’s Greater Bay Area that new research into coastal boat traffic has focused its efforts, honing in on a coastal megalopolis encompassing Guangdong, Hong Kong, and Macao – home to around 86 million people making it the largest population and the second-largest economy of any bay in the world.

It’s hoped that the findings from this particular study – one carried out by the Environmental Sustainability and Resilience Joint Centre which is a research partnership between the University of Exeter and the Chinese University of Hong Kong – could go towards aiding the planning and development of future coastal and marine conservation.

The paper, published in the journal Marine Policy, is entitled: “Spatial footprint of maritime vessels in the waters of a fast-growing coastal megalopolis.”

“We found that marine species are likely exposed to relentless presence of vessels,” said Dr Phil Doherty from the University of Exeter. “Put simply, boats and ships are everywhere, all the time.”

In shallow waters, like those of the Greater Bay Area, such traffic is likely to increase rates of shoreline erosion, turbidity (which is churned up sediment), noise pollution, and collisions with wildlife. This shallow water also means species cannot escape into the depths, leaving them with little refuge.

Analysing vessel tracking data from 2013 to 2018 and mapping precise locations and the daily distribution of marine traffic, researchers discovered that in some conservation hotspots, certain areas had experienced disturbance on 95% of days of all five years.

Dr Felix Leung from the Chinese University of Hong Kong, said: “With Hong Kong and Shenzhen hosting the busiest port in the world, the relentless pace of economic growth and development is taking a toll on the marine ecosystem.

“To safeguard these ecologically sensitive areas, governments must adhere to the Global Biodiversity Framework, ensuring both protection and sustainable management for future generations.”

Dr Stephen Lang from the University of Exeter believes the Greater Bay Area is “an interesting test case for coastal cities as they grow” adding that as pressure on marine environments near coastal cities increases, we now need to start thinking hard about how to “limit human impact.”

Action that could be taken to preserve areas for biodiversity and marine life include designating shipping lanes that avoid such key habitats, reducing vessel speeds and switching to quieter, less polluting vessels, and reducing shipping altogether.

Being home to animal species of conservation concern, including the Chinese white dolphin and the finless porpoise alongside populations of green turtles, Chinese horseshoe crabs, and mangrove horseshoe crabs, the Greater Bay Area does make for an interesting case study. Decades of extensive land reclamation have contributed to fundamental changes across the area that may put many of the species of marine life inhabiting it under threat. 

This is compounded by the fact that as well as high overall traffic, the Greater Bay Area hosts hundreds of fishing vessels which operate there daily.  

“We need to bring the environment into the conversation as development happens,” said Dr Lang.

A study published in the scientific journal Marine Policy earlier this year found that over the past decade, Chile had averaged five whale deaths a year due to ship collisions, with Sri Lanka and the US west coast following closely behind with three and four killed annually. 

Researchers now estimate that these numbers are just the tip of the iceberg, accounting for approximately 10% of the total deaths – just the carcasses of whales that are being found washed up on the coast.

This all lands as attention turns to the cost of human impact on the environment and the release of a cinematic experience and new book, Ocean – with David Attenborough, a feature length production looking at the destruction being caused to the seabed by overfishing and unsustainable fishing practices such as bottom-trawling. 

Released into cinemas this week to coincide with the 99th birthday of Sir David, the production brings together the biggest discoveries in marine science from the last 20 years, which itself includes the work of the University of Exeter. 

Oceanographic Magazine’s expert Columnist and head of marine biology at the University of Exeter, Professor Callum Roberts, reviewed the film’s script for scientific integrity and played a pivotal role in the development of the book’s chapter on coral reefs.

“For many years, scientists like me have been revealing, study by study, the massive impact that fishing using bottom trawls and dredges has on seabed life. This film brings the collateral damage done by industrial fishing into stark focus, but it also shows the amazing power of ocean life to regenerate when we protect it.”

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