Evidence of seismic blasting's harms are clear, but policy has not caught up

Far offshore, out of sight of most Australians, relentless industrial noise is echoing throughout our oceans.

Every 10 to 15 seconds, exploration vessels fire explosive bursts of compressed air into the water, searching for oil and gas deposits beneath the seabed. These seismic airguns operate around the clock for weeks and months at a time, generating sound levels that can exceed 250 decibels underwater, among the loudest human-made noises in the ocean.

To the fossil fuel industry, seismic blasting is a standard surveying technique. To marine life, it can be devastating.

A growing body of scientific research shows seismic blasting seriously harms marine ecosystems from the smallest plankton to the largest whales. The impacts are not isolated; they ripple through the entire ocean’s food web.

Whales and dolphins rely on sound to survive. They use it to navigate vast distances, find food, communicate with their pods, and locate mates. Intense acoustic shockwaves from seismic blasting airguns drown out those signals, disrupt migration routes and feeding behaviour, and have been found to cause hearing damage and even death.

Scientists have observed whales altering their songs and abandoning feeding and breeding grounds during seismic blasting surveys. For species already under pressure from climate change, ship strikes, overfishing and entanglement in fishing gear, these disturbances can be significant.

But the effects extend far beyond marine mammals.

Research from the Institute for Marine and Antarctic Studies, led by Ryan Day, shows seismic blasting can kill zooplankton – including krill and copepods – more than a kilometre from the source. These microscopic organisms underpin the entire marine food web. Krill feed whales. Zooplankton feed fish. Remove them, and the stability of an entire ecosystem begins to unravel.

Other studies have found seismic blasts can kill scallops, weaken crustaceans by affecting their immune systems, and disrupt the behaviour of fish and other marine species. Many animals – including octopus and fish – spend their earliest life stages drifting as fragile larvae in the water column, making them particularly vulnerable to acoustic shockwaves.

This is why seismic blasting is not just a wildlife issue. It is an ecosystem issue. It affects fisheries, coastal economies, and the long-term health of the ocean itself.

Yet despite these risks, seismic blasting remains routine because it sits at the beginning of the fossil fuel extraction process.

Before any offshore oil or gas field can be drilled, companies first blast the seabed to map geological structures. Seismic surveys are therefore embedded in almost every stage of fossil fuel exploration.

The same technology is also increasingly proposed for offshore carbon dumping, Carbon Capture and Storage (CCS) projects. Seismic surveys are used to identify potential storage formations and are repeated – on average, every five years – to monitor underground carbon dioxide reservoirs for any leaks or ‘migrations’.

The expansion of CCS in our ocean risks extending the same acoustic footprint already linked to fossil fuel exploration and harm across marine ecosystems.

Communities around the country are pushing back.

In south-eastern Australia, coastal residents, fishers, scientists and Traditional Owners united in a campaign to stop multiple large-scale seismic blasting proposals in the Otway Basin. One project would have covered over seventy thousand square kilometres of ocean between Victoria and Tasmania, including habitat used by endangered pygmy blue whales.

A similar movement is now emerging in Western Australia, where communities around Dongara and the Mid-West coast are raising concerns about offshore exploration proposals that could involve seismic blasting.

The political debate around seismic blasting in Australia did not begin recently. It has been building for years.

In 2018, Tasmanian Greens senator Peter Whish-Wilson successfully pushed for a Senate inquiry into seismic testing for offshore oil and gas. The inquiry heard extensive evidence from scientists, fisheries, and conservation groups about the impacts of seismic blasting on whales, fish stocks and plankton.

It found growing evidence that underwater noise pollution can disrupt behaviour, damage hearing, and harm early life stages of marine species – underscoring the need for far stronger protections.

Six years later, in 2024, Kooyong independent MP Monique Ryan introduced the Abolition of Special Prospecting Authorities (Ocean Protection) Bill 2024, seconded by Liberal MP Bridget Archer, to end the issuing of seismic blasting Special Prospecting Authority permits. These permits allow speculative and repeated exploration of vast ocean areas. This bill was put forward as part of efforts to declare a moratorium on seismic blasting for fossil fuels, and to put an end to offshore fossil fuel approvals.

Taken together, the inquiry and the bill tell a clear story. The science has been heard. The policy response has been proposed.

What remains is political will.

Australia already possesses decades of geological data from previous surveys, much of it held by Geoscience Australia. Our offshore basins are among the most extensively mapped anywhere in the world.

Continuing to blast vast areas of ocean in search of new fossil fuel reserves is increasingly difficult to justify, particularly as Australia moves toward cleaner energy.

Our oceans are under immense pressure from climate change, warming waters, coral bleaching, overfishing and pollution. Adding relentless underwater explosions to that list only compounds the damage.

Now is the time to act: revive and implement the reforms proposed in Dr Ryan’s bill, heed the warnings of the Senate inquiry and end seismic blasting of our oceans.

The ocean does not need more blasting. It needs protection.