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St Croix Island penguin colony decline - Professor sets the record straight

St Croix Island, off the coast of the Eastern Cape, is home to the largest African penguin colony in the world. Picture: Ian Landsberg/African News Agency (ANA) Archives

St Croix Island, off the coast of the Eastern Cape, is home to the largest African penguin colony in the world. Picture: Ian Landsberg/African News Agency (ANA) Archives

Published Jun 17, 2022

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Before the commencement of ship-to-ship fuel transfers, an estimated 23 000 endangered African penguins were living and breeding on St Croix Island, Algoa Bay. This was the largest single colony on the planet but, after only six years of fuel transfers, only 3 000 penguins are left.

On May 23, an oil spill occurred while a ship-to-ship fuelling procedure was under way. The spill occurred when Minerva Bunkering Services mothership tanker vessel Umnenga II was transferring heavy marine fuel oil to their transfer vessel Lefkas while positioned at Anchorage 2, which is located on the boundary of the Addo Marine Protected Area, and close to Brenton Island.

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It was reported that a pipe had ruptured, allowing an estimated 3 000 litres of low sulphur heavy marine fuel oil to spill into the ocean. Emergency procedures were activated, and spill clean-up teams commenced work.

Clean-up continued over the following four days assisted by spotter aircraft tracking the oil drift towards the sensitive bird islands. Notwithstanding the spill response efforts, the oil was dispersed as a surface sheen over an extended surface area in the direction of the St Croix islands and towards Bird islands.

St Croix Island, off the coast of the Eastern Cape, is home to the largest African penguin colony in the world. St Croix, along with Bird, Robben and Dassen islands, is part of a research study to establish the effects of fishing on penguin breeding and foraging behaviour.

Historical references paint a picture of the island as "brown with seawolves (seals) and white with birds" in 1575. It took just four years during the 1820s for humans to wipe out the seal population.

As with Dassen Island, penguin eggs by the thousand were removed for human consumption, halting only around 1956. And guano harvesting resulted in all its soil finding its way onto foreign ships to serve elsewhere as fertiliser. This is why most of these islands are just rocky outcrops today.

Today, people are not allowed to land on the group of islands, although some charter boats cruise close enough to enable one to see the penguins quite easily. Fishing exclusion zones have been put in place 20km around the islands, with three years on and three years off, to see the effect on the penguins.

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According to Algoa Bay Conservation, “reports from the spill site confirm the vast spread of the oil slick drifting eastwards. Media reports that the oil did not reach the sensitive bird breeding and nesting islands and therefore not impacted on seabirds is misleading because the birds forage throughout the affected oil drift areas.”

On April 23, 2022, an oil spill was detected by vessel tracking, in the same area involving Umnenga II and transfer vessel Kimolos, both operated by Minerva, and confirmed by clean-up operations. Oiled sea birds were recovered from Bird Island on May 3, 2022.

Professor Lorien Pichegru from Nelson Mandela Metropolitan University, Coastal and Marine Research Institute took to Facebook to set the record straight regarding unsubstantiated media reports that the ship-to-ship refuelling operations did not impact sea birds in Algoa Bay.

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“There seems to be a need to set records straight about the St Croix Island penguin colony from an expert who has been conducting research for the past 15 years on the impacts of various anthropogenic threats on African penguins in Algoa Bay,” said Pichegru.

“I counted a population count on St Croix Island a few months ago on behalf of the Department of Forestry, Fisheries and the Environment, with the help of South African National Parks. We counted over 1 000 breeding pairs, which makes for approximately 2 500 penguins, accounting for those that do not breed,” she said.

This is a 90% decrease from a decade ago, while the Bird Island penguin colony halved during the same time. The professor added that penguins do not move once they have started breeding in a colony, thus penguins have died and not simply moved away as implied by reports.

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“African penguins from all over South Africa are decreasing at an alarming rate, and so are Cape gannets and Cape cormorants, all three being endangered, all three depending on small pelagic fish, sardines and anchovies, as prey,” continued Pichegru.

The small pelagic fish stocks have dwindled recently due to, among others, climate change. We cannot change the climate to improve conditions for fish, to increase food availability for the seabirds. Pichegru said that fishing exclusion zones need to be established and monitored around penguin and sea bird colonies.

“My research has proved repeatedly over the years the benefits of sardine fishing exclusion zones around penguin colonies for the breeding birds. It was confirmed on the West Coast colonies by colleagues of mine. However, no effective closures have been set in place to date for the past two years, despite the promises by the minister. These are urgently needed,” she said.

St Croix Island is particularly vulnerable due to its location in the lea of the bay, which limits the size of the foraging habitat of penguins. Changes in prey availability are felt much more rapidly by penguins breeding there.

In addition, the proximity of two industrial harbours increases noise pollution levels in the penguin’s foraging habitat, and bunkering activities significantly increase the risks of oil spills, as shown by the four oil spills that occurred in the bay since 2016, the initiation of the ship-to-ship bunkering in the bay.

“Noise pollution is something we only recently start acknowledging globally, and my latest research (submitted for publication) shows that noise levels in the bay have doubled since 2016, likely affecting many levels of the ecosystems. Fish, invertebrates, birds and marine mammals use sound to communicate, find food, find mates, locate predators etc. Penguins are canaries in the coal mine, revealing the troubles underwater we cannot see.

“Noise mitigation measures will need to be set in place and discussions with SAMSA are ongoing,” concluded Pichegru.

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