Mauritius Oil Spill and Artificial Reefs

Could sunken subways, airplanes and ships help protect marine life?

Writer: Alexander Hancock
Editor: Chelsea Tripp
Artist: Patrick Marenda

As the social and economic devastation brought on by the global pandemic continues to dominate headlines and flood social media, our attention towards the environment has all but taken the back seat in 2020; a year that was widely considered a pivotal period in reversing the persisting hazards of climate change. And while the launch of Prince William’s new £50 million environmental initiative Earthshot Prize was met with plaudits from activists around the world, others denounced the royal, claiming the arrival of his project was ill-timed considering the ever-growing issues related to COVID-19. But can we afford to let the environment fall on our list of priorities?  

The catastrophic oil spill in Mauritius arguably typifies how stories regarding the environment have been overshadowed by the crisis that is COVID-19. Since 25th July, approximately 1,000 tonnes of diesel and fuel oil have spilled into the idyllic waters surrounding south-east Mauritius, after the hull of a Japanese cargo ship fissured when it struck a shallow reef. The resulting contamination has decimated the protected marine environment which is known for its rich biodiversity, coating the shoreline in thick oil and polluting the surrounding waters. Home to over 1,700 species ‒ including parrotfish, swordfish, green turtles and dugongs ‒ along with an abundance of reefs, lagoons and mangroves, the ecosystems impacted by the spill face potentially irreversible damage. Anxiety surrounding the dissemination of oil was raised when it was discovered that the spill had extended to two rivers that connect to the bay. But perhaps the greatest concern relates to the low-sulfur fuel that was released into the ocean following the shipwreck. A relatively novel type of fuel that is used to minimise air pollution, the ecological effects of low-sulfur fuel on marine ecosystems are yet to be studied.

While we often hear of oil spills and their detrimental impact on aquatic ecosystems, how exactly do they affect marine life and what are their immediate and delayed implications? One of the greatest threats to both marine ecosystems and avian communities are oil slicks; the thin layer of oil that materialises on water following a spill. Responsible for the death of over 250,000 seabirds after the Exxon Valdez disaster, bird communities are particularly vulnerable to slicks, as they consume fish that have been exposed to oil. Risks of ingestion include birth defects, for example egg-shell thinning in offspring, and in most cases, death. The oil from spills may also cover the plumage of birds, hindering their ability to fly and causing the matting of their feathers which impacts their capacity to conserve body heat

Coral reefs ‒ which are fundamental to maintaining the balance of ecosystems ‒ undergo irreparable damage from the chemical components of spills that sink to the ocean floor. Other than the risk of toxic components seeping into the coral, reefs are highly dependent on sunlight for the process of photosynthesis. As oil blackens the water, it reduces the amount of sunlight reefs receive and engenders tissue swelling and ruptures in corals. Zooplankton, which corals consume, may die as a result of oil pollution, further disrupting the marine food chain. Oil pollution can also cause the asphyxiation of mangroves ‒ the trees that grow along shores and estuaries ‒ when chemicals coat the plants’ breathing pores, otherwise known as pneumatophores. Similarly, seagrass ecosystems in coastal waters can also experience smothering and contamination, significantly impacting the aquatic life that relies on it as a food source. Saltwater fish and turtles are susceptible to anatomical changes due to the consumption of toxic residues from oil, including reduced growth, enlarged livers and reproductive impairment.

Humans also face health risks brought upon by oil spills. Other than the risk of eating fish that have been exposed to toxic compounds from spills, once oil evaporates, it can contaminate the air we breathe, causing respiratory issues, liver damage and increased cancer risk.


The July oil spill poses profound risks to the island of Mauritius with regards to its environmental preservation efforts, but also its economic prosperity. The country’s economy is heavily reliant on tourism ‒ which generates US$4.3 billion annually ‒ as it is on its prosperous fishing industry, which has suffered greatly due to pollution on the island’s coastline. As a result, non-profit organisations and groups of volunteers have hastily deployed several schemes to clean up its waters. Since the Government announced a national environmental emergency, containment booms were employed to protect the shoreline ‒ some of which were composed of hay and human hair ‒ though the central focus has been on removing fuel from the ship, of which 3,000 tonnes have been pumped. And while Mauritius officials have successfully removed 400 tonnes of fuel from the ocean, the clean-up operation has been riddled with controversy and confusion. The peak of this dissension was reached when the front half of the ship was purposefully sunk on 24th August, despite claims that there was still oil inside the vessel. Many environmentalists have attributed the death of fifty whales and dolphins that have washed up on the shores of south-east Mauritius to the sudden sinking of the ship.

If scientists predict that 70-90 percent of the world’s corals reefs will disappear over the next twenty years, how can we protect marine ecosystems that are constantly at risk of contamination from oil pollution? One solution ‒ used by Japanese fishermen in the 17th century to increase fish populations ‒ is the employment of artificial reefs: submarine structures that are sunk to the bottom of the ocean, with the goal of preserving and promoting marine ecosystems. Examples of artificial reefs include old ships, planes, cars, subway carriages and tanks. Over time, the eerie remnants of old used vehicles and forgotten items become covered in marine growth, such as algae and corals, attracting fish and marine mammals and creating a home for rich biodiversity. Artificial reefs provide closed and protected spaces for smaller fish, who would otherwise be exposed in the vastness of the ocean, while fostering a feeding ground for larger fish and aquatic mammals. Other advantages of artificial reefs include establishing tourism sites for scuba divers, which boost the country’s economy while drawing tourists away from vulnerable natural reefs.

Yet despite the supposed environmental and economic promise of artificial reefs, they are an intrinsically contentious concept, causing concern amongst scientists who argue for the potential of contamination and lack of durability. Research suggests that variations of artificial reefs emit toxic materials including black carbon and zinc oxide, which could damage ecosystems. Skeptics have also raised concerns surrounding the robustness of artificial reefs containing scrap tyres, questioning whether their structure can withstand strong ocean currents and marine debris.

The cause of the environmental disaster in Mauritius has polarised many, with some claiming the spill was caused by the use of the wrong electronic nautical chart, while others suggest it was a result of a party on board that distracted the ship’s captain from determining the vessel’s proximity to shallow waters. In the midst of this finger-pointing and casting of blame, perhaps the greatest takeaway from the spill is how our reliance on fossil fuels has produced social and environmental destruction. If the pollution caused by the burning of fossil fuels accounts for an estimated 4.5 million deaths each year worldwide and for annual global economic losses totalling US$2.9 trillion, it is no wonder that policymakers around the world are advocating for drastic changes to coal and oil production. And yet, while the potential for artificial reefs to create hubs for ecosystems has proven promising, the seismic shifts in the protection of marine life that we so desperately want won’t take place until the need to transport oil ‒ or more generally, the need for oil ‒ ceases to exist. 

The imminence of continued lockdowns, coupled with the race for a successful vaccine, will undoubtedly occupy our thoughts and concerns for the next couple of months ‒ and understandably so. Yet if we continue to neglect the pressing environmental issues that have taken place since the start of the pandemic, including the Australian and US wildfires, Typhoon Vamco in the Philippines and of course, the Mauritius oil spill, our hopes for a better 2021 may be wishful thinking.

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