Study calls for limits to offshore bunkering

Modelling oil spill behaviour highlights risks

SOUTH AFRICA: A new study funded through a grant by the Oiled Wildlife Care Network (OWCN) concludes that, until high levels of environmental rules, scrutiny and compliance is applied, offshore ship-to-ship bunker operations should not be permitted in areas such as Algoa Bay.

The paper, which focuses on the period between 2016 and 2024, notes that more than half of the 378 oiled seabirds that were admitted to rehabilitation centres in this time were linked to STS related spills. The authors also highlight that literature shows that 7% of annual global spills originate from bunkering operations.

Linking the collapse of the local colony of African penguins in Algoa Bay to a combination of bunkering activities, harbour developments and increase in shipping activities, the study emphasises the impact of maritime activities on this vulnerable species.

It is estimated that around 2,600 litres of oil have been spilled during bunkering operations across four separate incidents affecting some 186 penguins, 15 Cape gannets and three Cape cormorants. Causes of the spills include overflowing tanks as well as malfunctioning hoses and valves during the transfer. In one case, bunkering is said to have been undertaken in bad weather.

The paper concentrates on the 2019 spill when approximately 400 litres of bunker fuel spilled during a transfer to MV Chrysanthi, likely due to a leaking valve. Recognising that oiled birds were found up to 200 km from the nearest breeding sight where most of the impact was seen, the authors surmise that the actual number of marine birds affected by spills is likely higher than the number admitted to rehabilitation centres.

By creating models of the MV Chrysanthi, the aim of the study was to predict the outcome of spills at different locations and across seasons in Algoa Bay. According to the findings, relatively small amounts of oil can affect relatively large areas, depending on the prevailing wind and current patterns at the time of the spill.

“While spills from STS bunkering activities in both anchorage areas one and two had significant negative impacts in the bay and the foraging areas of seabirds, spills originating in the southern section of anchorage area 2 would have even larger impacts, as oil would spread further south and in larger part of the seabirds' foraging area. Therefore, STS bunkering activities should not take place in anchorage area two to limit risks to seabirds,” they write.

Describing the historic and current regulatory oversight being enforced in the bay, the paper notes the gazetting of the environmental management regulations by the Department of Forestry, Fisheries and the Environment (DFFE) this year, but submits that these “fall short on protecting wildlife in Algoa Bay”.

REPORT: Evaluation of risks of oil contamination in endangered seabirds in Algoa Bay, South Africa, linked to ship-to-ship bunkering and anthropogenic maritime activities. Authors: Katrin Ludynia, Monica Stassen, Giles Fearon, Lorien Pichegru.