A two-year FRDC-funded study is investigating different seismic survey methods that could protect fisheries while giving oil and gas explorers the data they need
By Chris Clark
Southern Rock Lobsters exposed to seismic blasts are collected for longer-term monitoring of the impacts. Photo: Davis Huston
Following a growing number of studies that identify the impact of traditional seismic survey techniques on marine species, FRDC has backed new research in Bass Strait to investigate alternative technologies.
The project focuses on two species, the Commercial Scallop (Pecten fumatus) and the Southern Rock Lobster (Jasus edwardsii).
The project’s principal investigator is Dr Ryan Day from the Institute for Marine and Antarctic Studies (IMAS) at the University of Tasmania. He says there is an urgent need to compare the current industry standard seismic techniques to alternative methods and determine the relative impact of each on marine animals.
“It would move us into a position to start mitigating the impacts of seismic surveys, rather than the situation we currently have, where each individual seismic survey causes a large degree of angst for a large number of stakeholders,” he adds.
IMAS has partnered with Curtin University in Western Australia on the project. Both have a long history of researching scallops and rock lobsters and the impacts of seismic surveys. FRDC has provided funding and support, and Beach Energy has funded critical access to a seismic survey vessel.
Other partners include the Bass Strait Scallop Industry Association, which represents commercial scallop fishers working the Commonwealth Bass Strait Central Zone Scallop Fishery, and Tasmania’s Department of Primary Industries, Park, Water and Environment. Ryan says that research from 2012 to 2016 showed that standard air gun seismic surveys damaged the biochemistry of the scallop haemolymph – the equivalent of its blood.
“Scallops weren’t able to regulate the different components of the blood, which indicates they were physiologically compromised. They changed their behaviour as well. They tended to bury themselves more quickly into the sand when exposed to seismic waves – the higher the seismic level, the more quickly they recessed into the sand,” Ryan says.
In the case of rock lobsters, research found that the sensory organ that functions in a similar way to a human inner ear is principally affected, impacting their sense of gravity and movement. “Seismic activity impaired their coordination, so they couldn’t easily right themselves when placed on their backs,” he explains.
In the current research project, the research team placed scallops and lobsters in baskets 60 metres down onto the sea floor off King Island, in western Bass Strait. The animals were then subjected to three different seismic techniques: an industry standard approach and two emerging seismic techniques.
To test the standard technique, a seismic testing vessel was fitted with three arrays of seismic air guns. “Each array totalled about 2480 cubic inches of air gun volume, which is a pretty standard set-up for a seismic survey,” Ryan says. The second technique used only one of the three seismic arrays to reduce the total volume of air guns.
The third technique, known as eSourceTM, has been developed by Beach Energy. It gradually releases air bubbles to create sound waves with reduced high frequencies.
Ryan says the different techniques being trialled respond to existing knowledge about which sound frequencies may be most damaging to marine animals.
The techniques have also been applied at different distances – directly above the scallops and lobsters, and at 500 and 1000 metres distance – because research shows that seismic impacts on marine animals vary with distance.
“If we can provide survey operators with a 500 or 1000-metre range, that at least gives them something to work on,” he says.
Evaluating seismic impacts on marine animals is a complex, multidisciplinary task, and Ryan says there are a lot of questions requiring answers.
“When we first started in this field of research, we concentrated on the intensity of the pressure wave that is created. But in recent years, we’ve started looking at another characteristic of seismic waves, known as particle acceleration, which is how, over short distances, the wave is moving water or anything else,” he explains.
“In our earlier work on scallops, we think that the shaking of the ground as a result of an air gun was what caused the damage, and that’s something we’re just starting to get a handle on measuring and evaluating,” he says.
Earlier research has already observed general indicators of damage to scallops and lobsters, and the new project is starting to delve a little deeper into those impacts. This includes more sophisticated measures such as oxidative stress indicators, DNA damage and immune function.
The researchers also know that impacts vary over time. After being exposed to seismic waves in Bass Strait, the scallops and lobsters have been taken back to the IMAS research facility in Hobart and put in tanks to be analysed three months after exposure and again six months after exposure.
“When we did our first scallop study, we noticed increasing mortality over time, particularly at the highest level of seismic exposure,” says Ryan.
Commercial Scallops exposed to seismic surveys are monitored in tanks at the University of Tasmania. Photo: Davis Huson
That also ties in with anecdotal reports by scallop fishers, according to Andrew Sullivan, the Executive Officer of the Bass Strait Scallop Industry Association.
“Going back over a decade ago, a few months after some seismic surveys, scallop fishers started dredging up dead scallops east of Flinders Island, but we weren’t able to gather the scientific evidence at the time to prove a link,” he says.
“Ten or 12 years ago, there wasn’t a recognition that seismic surveys could have that impact on scallops. In the meantime, I think it’s fair to say, there’s probably been a lot of angst between the commercial fishing industry and oil and gas companies because of conjecture over the impacts,” Andrew adds.
Beach Energy is assisting with vessels and technology to assess the impact of different survey technologies. Photo: Davis Huston
“Ten or 12 years ago, there wasn’t a recognition that seismic surveys could have that impact on scallops. In the meantime, I think it’s fair to say, there’s probably been a lot of angst between the commercial fishing industry and oil and gas companies because of conjecture over the impacts.” Andrew Sullivan
He says his members don’t oppose oil and gas exploration because they rely on the end products but they believe the most effective way to limit damage is to find the technology that is least damaging.
Andrew says that, while legislation requires seismic surveys to have impacts as low as reasonably practicable, without research to find lower impact methods the benchmark won’t change from current industry standards. “If we know that one seismic method has a lower chance of impact and still delivers the level of information the oil and gas companies need then, straightaway, we can say ‘let’s use that’.
“My view is that the fishing industry needs to base its engagement with the oil and gas companies on better data. To Beach Energy’s credit, they have been extremely supportive of that approach by helping to fund this research project,” he says.
The research project runs until September 2023. f
More information
Ryan Day - ryan.day@utas.edu.au
