Seismic surveys risk to penguins
NMU research findings raise fears for health of species
NEW research by Nelson Mandela University scientists shows for the first time how endangered African penguins move away from their preferred feeding areas during seismic surveys. The noise of the equipment used to capture information for geological surveys adds further stress to a species already threatened by overfishing, reduced and shifting stocks of sardine on which they feed, and oil pollution.
Down 70% since 2004, the two largest surviving African penguin colonies are on St Croix and Bird islands in Algoa Bay, at the heart of a swathe of offshore oil and gas exploration licence applications which the Petroleum Agency of South Africa has either granted or is considering.
In the latest move, the Department of Mineral Resources has approved an exploration application from British company Petroleum Geo-Services, which aims to start surveying in the Algoa Bay area this month.
NMU penguin specialists Dr Lorien Pichegru, Reason Nyengera (now at Birdlife South Africa), Dr Alistair McInnes and Dr Pierre Pistorius wrote the report on the impact of seismic surveys which was published in Scientific Reports, an online journal of Nature.
Seismic surveys use arrays of air guns towed behind the exploration vessel.
The air guns emit sharp, loud sounds which bounce off the seabed, capturing information about the minerals and gas beneath.
Although this acoustic energy is directed at the seabed, a considerable part travels sideways and is detectable up to 50-75km from the sound source in shallow waters and up to 4 000km in deep waters.
“Some seismic operations can extend over 50 000km² and can operate continuously for months,” the report said.
“With the ever-increasing demand on energy in recent years, both the frequency and total area surveyed by seismic activities has dramatically expanded, with impacts on marine fauna of growing concern.”
Previous research had already shown how seismic surveys negatively affected a range of sea life from whales to fish and plankton, but until now no evidence had been available of it affecting seabirds, the report said.
However, it had been expected, and to test the theory, 333 birds from St Croix and Bird islands were fitted with tiny GPS loggers. Data was collected from 333 separate foraging forays in the period March-May from 2009-2013.
In its key finding, the report says: “Penguins foraging less than 100km from active seismic operations showed a clear change of foraging direction [an average 50km] during seismic periods, increasing the distance between their feeding area and the location of the seismic vessel.”
Given proven findings of how seismic surveys affect other sea life, research should now be done to ascertain whether they temporarily or permanently damage the penguins’ hearing, disrupt their communication systems, reduce foraging efficiency and increase energy expenditure.