It's understood Schlumberger Australia Pty Ltd have commenced a 100-day operation in a bid to find potential recoverable hydrocarbon - natural gas, oil and coal - in a 93,000 square kilometre area of the basin including off the entire south-west coast.

It comes after the coronavirus outbreak halted crayfish exports across the country.

Port Campbell cray fisherman Wayne Hanegraaf has thanked his lucky stars that he decided to sit this season out.

This is the second time he has seen seismic testing rock the region's cray industry, telling The Standard in an earlier interview that it nearly killed the industry altogether.

"The cray boys are going to have a hard time over the next six months, that paired with the virus," he said.

"The seismic testing is what really worries everyone, we've felt in the past that they've never really told us the true number of casualties and what they're killing.

"Out the back they use a different type of testing, much heavier, whereas in the shallows they're not as radical.

"They do it no matter what we say."

The operation, expected to wrap up in June, involves a seismic survey vessel M/V Nordic Explorer towing an array of air guns that release blasts of 259 decibels every 10 to 15 seconds, 24 hours a day, seven days a week.

Lisa Deppeler, spokeswoman for the Otways Climate and Environment Action Network (OCEAN), said the impacts on marine life could be devastating.

"At the moment there is a Senate Inquiry into the effects of seismic blasting because not enough is known about the negative impacts on marine life," she said.

"Studies have shown seismic blasting kills scallops and vast areas of krill and zooplankton. Whales and dolphins are impacted negatively but we don't know to what extent.

"Local fishermen report areas that are void of crayfish for years, post seismic testing.

"At a time when our country is burning and we should be transitioning away from fossil fuels, this vandalism of our marine environment is just crazy."

The exploration was approved by Australia's offshore energy regulator NOPSEMA and Resources Minister Matt Canavan.

Schlumberger describes itself as the world's leading provider of technology for reservoir characterisation, drilling, production, and processing to the oil and gas industry.

A statement on NOPSEMA's website claims marine mammal observers and passive acoustic monitoring observers will be on board the vessel to observe for whales.

Schlumberger failed to respond to The Standard's contact for comment.

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