Conservation

Avoidance of seismic survey activities by penguins

Posted on the 14th December 2017

Avoidance of seismic survey activities by penguins

For the very first time African Penguins (Spheniscus demersus) are shown to be strongly affected by seismic surveys exploring the seabed for petroleum and natural gas in Algoa Bay, South Africa. Research published this month in Scientific Reports, a Nature affiliated journal, shows that African Penguins avoided seismic survey areas. 

African Penguins are endemic to southern Africa and are among the most loved birds in the world, but they are in jeopardy – the population has decreased by 70% since 2004. This has raised grave concerns about human impacts on penguins. Underwater noise pollution is now recognized as a significant threat to marine life, but until now the impact on penguins was unknown. As penguins are flightless and spend long periods of time at sea, they are likely to be the most susceptible to loud sounds as they have a limited ability to escape.

Seismic surveys explore subterranean geological features for petroleum, natural gas and mineral deposits. Arrays of sound air guns are towed behind a vessel at 4-8 m below the surface. These sound air guns emit loud blasts of sound at between 230 and 255 dB. In comparison the pain threshold for sound pressure in humans is 120 dB. But the sounds also travel horizontally and can be detected up to 50–75 km from the sound source in shallow waters and up to 4000 km in deep waters. With the ever-increasing demand for energy in recent years, both the frequency and total area surveyed by seismic activities has expanded dramatically, with impacts on marine fauna of growing concern.

Breeding penguins were equipped with GPS recorders, to examine their foraging behaviour before, during and after seismic operations conducted within 100 km of their two largest breeding colonies, both in Algoa Bay, home to approximately half of their global population.

Results from the GPS data analysis indicated that penguins foraging <100 km from active seismic operations changed their foraging direction during seismic periods as well as increased the distance between their feeding area and the location of the seismic vessel.“To our knowledge, this is the first record of avoidance behaviour by a seabird to sounds generated from anthropogenic activities at sea”, says Dr Lorien Pichegru, lead author of the study and a research associate at the University of Cape Town and Nelson Mandela University. “This kind of avoidance behaviour may be explained by either direct disturbance from the operational noise or a change in fish distribution during that period, possibly because of seismic activities” says Dr Pierre Pistorius, coauthor and senior lecturer in Zoology at the Nelson Mandela University. “However, we cannot disentangle the two effects.”

“Anthropogenic sounds may directly or indirectly perturb other long term crucial life history traits of our precious penguin population. We therefore recommend a more proactive engagement between researchers, management authorities and the petroleum companies in assessing prospects before they are passed” says Reason Nyengera, who completed the work as part of his Masters’ thesis and now works for BirdLife South Africa. The authors urged the exclusion of seismic exploratory activities within 50 to 100 km of penguin colonies.

 

 

 

 

 

 

 

 

 


COMMENTS

625
DI PARKER (posted: 2017-12-14 14:17:35)
We are without doubt the most destructive species on the Planet, with our misguided sense of our own importance