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Timor Sea oil spill research on agenda in US

By Leanne Coleman

Sea turtle expert Dr Michael Guinea, who has spent the past two years researching the impacts of the 2009 Montara oil spill Sea turtle expert Dr Michael Guinea, who has spent the past two years researching the impacts of the 2009 Montara oil spill

A sea turtle expert who has spent the past two years researching the impacts of the 2009 Montara oil spill on one of northern Australia’s most pristine and protected marine habitats will present his findings in the United States this month.

Charles Darwin University’s Dr Michael Guinea and his team spent 1280 hours conducting underwater surveys covering 20,000 hectares of reef crests, and covered more than 300 km of reef flats and lagoons on boat surveys.

“On 24 August 2009 a sudden ingress of gas into the well bore of the West Atlas Oil Rig on the Montara field resulted in an uncontrolled flow of hydrocarbons into the Timor Sea,” Dr Guinea said.

“The Montara exploration field sits 200 km north of the Australian mainland near the centre of the Sahul Shelf stretching along the Timor Sea to the Tiwi Islands. A rich diversity of flora and fauna thrives in marine and terrestrial protected areas in the productive oil and gas fields of the Sahul Shelf.”

Research by the team aimed to assess the long-term impacts of the oil release on sea turtles in marine protected areas in the Timor Sea, including Ashmore Reef and Cartier Island.

“These areas have large sea turtle populations and were potentially impacted by the spill,” he said. “We drew on pre-impact data collected over the past 20 years and compared reefs that were potentially impacted with reefs that were clear of the modelled and observed surface slick.

“We also conducted boat and in-water surveys, beach surveys on nesting marine turtles and hatching success of recent nests, and assessed changes in blood chemistry of foraging juvenile green sea turtles from Ashmore Reef and Montgomery Reef.”

Dr Guinea said the survey found no detectable impact on these important populations.

“There was no detectable impact on the number of nesting marine turtles,” he said. “Results of the blood biochemistry parameters of juvenile green sea turtles were within the reference values from pre-impact surveys and un-impacted sites.

“There was a decrease in marine turtle and sea snake numbers in the 12 months between surveys at one of the un-impacted reefs Seringapatam Reef. We are still working to ascertain the reason for the decrease.”

Dr Guinea said long-term research was vital for continued understanding of the behaviour of marine animals to inform conservation management and understand any future impacts.

In March 2012 and 2013 PTTEP Australasia Pty Ltd, commissioned impact assessment and monitoring surveys of the region and its biota to assess the long-term impact of the uncontrolled release on the marine turtles and sea snakes of the Timor Sea.

Dr Guinea has been researching the impacts of pollution on sea turtle and sea snake populations in northern Australia for more than 20 years. He will present his paper entitled “Long-term Impact of the 2009 Montara Oil Release on the Sea Turtles of the Timor Sea” at the 34th Annual Symposium of Sea Turtle Biology and Conservation at New Orleans on April 16.