Marine airgun noise could cause turtle trauma
Scientists from the University of Exeter are warning of the risks that seismic surveys may pose to sea turtles. Widely used in marine oil and gas exploration, seismic surveys use airguns to produce sound waves that penetrate the sea floor to map oil and gas reserves.
The review, published in the journal Biological Conservation, found that compared to marine mammals and fish, turtles are largely ignored in terms of research attention and are often omitted from policy guidelines designed to mitigate the environmental risks of seismic surveys.
Possible ramifications for turtles include behavioural changes and exclusion from critical habitats as well as potential auditory damage, as turtle hearing ranges overlap with airgun frequencies. In addition, turtles are known to become entangled in gear towed behind the survey vessel, which can lead to drowning.
Lead author Sarah Nelms from the Centre for Ecology and Conservation at the University of Exeter's Penryn Campus in Cornwall said: "By talking to oil and gas companies, seismic operators and on-board Marine Mammal Observers, as well as academics and conservationists, we had a great opportunity to gather a broad spectrum of opinions, not just one side of the story. This allowed us to access information that was not available in the published literature."
The researchers also examined policy guidelines for the mitigation of risk to marine life in seismic surveys and assessed peer-reviewed literature on the topic.
"Our study reveals the potential for seismic surveys to cause behavioural changes and physical harm to turtles and we are calling for more research to urgently fill the crucial knowledge gaps that were highlighted during our review," said Ms Nelms.
During a survey, specialised ships simultaneously fire multiple airguns while towing multiple hydrophone streamers, which can cover an area up to 700m wide and 12km long, to capture the returning sound waves. Researchers involved in the study received reports of turtles becoming entangled in the trailing tail buoys and developed a turtle guard which has been voluntarily installed by some operators. Further research could help make such preventative measures mandatory in the future.
Senior author Professor Brendan Godley, also from the University of Exeter's Centre for Ecology and Conservation, said: "Seismic surveys are occurring in the waters of at least 50 countries in which marine turtles are present and they are becoming increasingly widespread. Given the conservation status of turtles, we feel that it is important and timely to assess the level of threat posed by this global activity and highlight knowledge gaps to direct future research efforts."
"There is a great deal that could be done proactively to help improve the status quo. We are standing by to work with seismic companies and others in the oil and gas sector to this end."
The researchers hope that their findings will assist with the development of policies to minimise the impact of seismic surveys on marine turtle populations, for example ensuring that they are not carried out during sensitive times or in critical areas, such as during breeding seasons or in foraging grounds.
This work was supported by NERC and the Darwin Initiative.
Seismic surveys and marine turtles: an underestimated global threat? By Sarah E. Nelms, Wendy E. D. Piniak, Caroline R. Weir and Brendan J. Godley is published in Biological Conservation.
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About the University of Exeter
The University of Exeter is a Russell Group university and in the top one percent of institutions globally. It combines world-class research with very high levels of student satisfaction. Exeter has over 19,000 students and is one of the global top 100 universities according to the Times Higher Education World University Rankings 2015-16, positioned 93rd. Exeter is also ranked 7th in The Times and The Sunday Times Good University Guide 2016, 9th in the Guardian University Guide 2016 and 10th in The Complete University Guide 2016. In the 2014 Research Excellence Framework (REF), the University ranked 16th nationally, with 98% of its research rated as being of international quality. Exeter was named The Times and The Sunday Times Sports University of the Year 2015-16, in recognition of excellence in performance, education and research. Exeter was The Sunday Times University of the Year 2012-13.
The University has four campuses. The Streatham and St Luke's campuses are in Exeter and there are two campuses in Cornwall, Penryn and Truro. The 2014-2015 academic year marks the 10-year anniversary of the two Cornwall campuses. In a pioneering arrangement in the UK, the Penryn Campus is jointly owned and managed with Falmouth University. At the campus, University of Exeter students can study programmes in the following areas: Animal Behaviour, Conservation Biology and Ecology, English, Environmental Science, Evolutionary Biology, Geography, Geology, History, Human Sciences, Marine Biology, Mining and Minerals Engineering, Politics and International Relations, Renewable Energy and Zoology.
The University has invested strategically to deliver more than £350 million worth of new facilities across its campuses in the past few years; including landmark new student services centres – the Forum in Exeter and The Exchange at Penryn – together with world-class new facilities for Biosciences, the Business School and the Environment and Sustainability Institute. There are plans for further investment between now and 2016.
About the University of Exeter's Centre for Ecology and Conservation (CEC)
Staff at the Centre for Ecology and Conservation, based on the Penryn Campus, undertake cutting-edge research that focusses on whole organism biology. The CEC has three interlinked research groups: Behaviour, Ecology and Conservation, and Evolution which constitute 40 academics and over 100 early career researchers. It engages widely with businesses, charities and government agencies and organisations in Cornwall, the Isles of Scilly and beyond to translate its research into societal impact. Staff at the CEC deliver educational programs to some 500 undergraduate and 100 postgraduate students.
A new £5.5 million Science and Engineering Research Support Facility (SERSF) is currently under construction at the Penryn Campus. The facility will bring pioneering business, science and engineering together and will provide space for the growing CEC alongside the University of Exeter Business School, which is expanding into Cornwall, and the University's Marine Renewables team.
The University of Exeter and Falmouth University are founding partners in the Combined Universities in Cornwall (CUC), a unique collaboration between six universities and colleges to promote regional economic regeneration through Higher Education, funded mainly by the European Union (Objective One and Convergence), the South West Regional Development Agency and the Higher Education Funding Council for England, with support from Cornwall Council.