PORT ELIZABETH, South Africa (AFP) — Generators hum loudly in the background as a tour boat bobs past a towering vessel filled with ship fuel, anchored in Algoa Bay, a stone's throw away from the world's largest breeding colony of African penguins.
Mid-way along the Europe-Asia sea route, the bay's deep-water port was an obvious choice for South Africa's first offshore bunkering operation.
Since 2016, mostly cargo ships have pulled in for ship-to-ship refueling, allowing them to carry more freight, bypass port fees and save time.
But conservationists, ecotour operators and nature lovers are alarmed about the long-term impact in a marine biodiversity hotspot and major foreign tourist magnet.
They claim the bunkering takes place too close to foraging and breeding grounds, disrupting the ecosystem and exposing sea animals to oil spills.
The risk has been highlighted by the catastrophic oil spill which began earlier this month into a protected marine park off the pristine coastline of Mauritius, after a bulk carrier ran aground on July 25.
With the main storage tanker in Algoa Bay able to hold 100,000 metric tons of fuel, opponents fear a potentially massive leak.
In two minor spills, in 2017 and 2019, rangers rescued dozens of oil-tarred penguins.
Scientists are also studying whether the noise, pollution and increased ship traffic could affect the marine animals.
They are particularly worried that vibrations caused by the activity may drive away those that rely on sonar to hunt fish.
"This is too close to the Marine Protected Area, there are too many risks involved…," warned environmental scientist Ronelle Friend, of the Algoa Bay Conservation community group, calling for an end to bunkering in the bay.
Follow the sardines
Algoa Bay — an inlet off the city of Port Elizabeth in the Eastern Cape province — is home to myriad species of seabirds, including just under half the global population of African penguins, classed as endangered by the International Union for Conservation of Nature.
The world's largest group of bottlenose dolphins was recorded in the bay in 2018, according to a report last year by the Port Elizabeth-based Nelson Mandela University.
The site is also on the path of an annual sardine run, touted as one of the planet's most spectacular marine events.
"This (bunkering) operation is slap-bang in the middle of a hotspot for bait fish that birds feed on," said veteran whale watcher and tour operator Lloyd Edwards, who has run his Raggy Charters marine tours in the area for over two decades.
"People used to be blown away by the amount of animals we had in this bay," he said, adding he'd noticed that certain whale species were not easy to spot since the STS refuelling started.
"They have all moved away," he complained, blaming the noise.
'Safe, regulated, environmentally friendly'
Three maritime companies have acquired bunkering licenses since 2016.
Between them, they operate the main storage vessel and up to seven smaller bunker barges, according to Kosta Argyros, the South Africa representative for one of the three, Minerva Bunkering.
Sat on a key trade route, sea traffic has increased as a result of the fueling hub, conservationists said.
Argyros stressed that bunkering was a "safe operation" in a "very regulated industry".
When "two vessels are tied together they become like one entity," he told AFP.
"This is environmentally friendly no matter what the people say."
South African Marine Fuels, which was behind the July 2019 spill, said it "occurred due to an overflowing tank of the receiving vessel" and that between 53 and 106 gallons of oil fell into the sea.
The company "is highly committed to the safety of its operations and responsibility to people and the environment," it said in a statement to AFP.