More and more offshore wind turbines are being installed around the coast of the UK as the country moves towards green energy options, but this move could be having damaging effect on at least of the marine species – seals – a new research has revealed.
Back in 2012 when wind turbines were being installed, Dr. Gordon Hastie of Sea Mammal Research Unit, University of St Andrews and other ecologists installed GPS/GSM tags on 24 harbour seals Phoca vitulina L to study the possible effects of pile driving associated with offshore wind farm construction.
Researchers combined the pile driving data, acoustic propagation models, and data collected from the GPS data loggers and predicted auditory damage in each seal. Models revealed that half of the tagged seals were exposed to noise levels that exceeded hearing damage thresholds.
Researchers reveal that though there is some information about the effects of noise on harbour seals’ hearing, little is known about the impact of the pulsed sounds produced by pile driving associated with installations. However, previous researches on the effect of such noise on humans and other terrestrial species have shown that powerful pulsed sounds can damage mammals’ hearing.
“These are some of the most powerful man-made sounds produced underwater, noise capable of travelling large distances underwater,” said Dr. Gordon Hastie, lead author of the Journal of Applied Ecology study. “Like most marine mammals, harbour seals have very sensitive underwater hearing at a much broader range of frequencies than humans. They probably use underwater hearing during the mating season and to detect and avoid predators. They may also rely on their hearing for navigation and finding prey.”
Researchers say that their results are important owing to the fact that seals are protected under European law and anything which might affect their conservation status needs to be assessed prior to the construction of wind farms.
Dr Hastie adds that their study highlights that seals may routinely be exposed to potentially hazardous levels of underwater noise during pile driving and this could have potential implications for the conservation status of some populations.
“To reduce these potential impacts, regulators and industry are currently investigating engineering solutions to reduce sound levels at source, and methods to deter animals from damage risk zones in order to potentially reduce auditory damage risk”, he adds.