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Seismic Testing and the effect on our marine environment

24 September 2017
– 6 Minute Read


On April 2010, an explosion on the offshore oil-drilling rig the Deepwater Horizon killed 11 crew and ignited a fireball that was visible 64km away. The fire could not be extinguished and, 2 days later, the rig sank, causing the largest oil spill in United States waters.

In the wake of the Deepwater Horizon disaster, there is an intense awareness of the dangers of drilling into the ocean floor to extract oil.  But what many don’t realize is that just exploring the sea – bed for oil or gas can put underwater ecosystems at risk due to a process known as seismic testing.

Maritime Review Africa reported on 6 September 2017 that an agreement between PetroSA, the oil and gas corporation of South Africa, and Rosgeo, geological exploration company of the Russian Federation, was signed at the 9th annual BRICS Summit to explore offshore oil and gas opportunities off the coast of South Africa.

The statement from PetroSA to Maritime Review Africa reads: “Within the framework of the agreement, Rosgeo is supposed to conduct a considerable volume of geological exploration work. It is planned to carry out more than 4 000 square km of 3D seismic operations and over 13 000 km of gravity-magnetic exploration works, as well as the drilling of exploratory wells. The estimated volume of the investment is about US$400 million”.

While the initiative is being lauded for the economic benefits to the country, at what expense will this be to our marine environment?

I recently attended the Maritime Law Association conference held from 1 – 3 September 2017 where Dr Jennifer Olbers, a marine ecologist at KZN Wildlife’s Scientific Services, gave an eye – opening presentation on seismic testing and its effect on the marine life.  

Seismic testing is the process used for mapping the ocean floor to determine where oil and gas is located so that the sea- bed can then be drilled and the resources extracted. The process involves Seismic air-guns sending compressed air streams or focused sonic waves – in simple language, loud booms – towards the ocean floor in order to gauge the depth, location and structure of the oil or gas resources.

The Oceana website reports that blasts from seismic air-guns, towed behind ships, are repeated every ten seconds, 24 hours a day, for days and weeks at a time.

Sound travels more easily under water than through the air and the noise from a single seismic survey can travel tens of thousands of square kilometres. An article in the Canadian Journal of Zoology reports that seismic surveys increase noise levels to twice the normal level, and impact marine life. Such surveys disturb the communication, navigation and eating habits essential to the survival of marine wildlife. These sonic waves can also damage fish with air bladders, destroy marine wildlife eggs and larvae, and cause fish and other marine species to temporarily migrate away from the affected area.

The effect of these blasts of sound on marine life is disturbing and can have catastrophic results: Seals have been found to display dramatic avoidance behavior, a slower heart rate, ceasing feeding and hauling out of the ocean. Turtles have shown reduced hearing sensitivity at a distance of 1km from the blasts. There have been damage to fish ears at distances of 500m to several kilometres, a reduction of 40 – 80% of catch rates in the North Atlantic and increased embryonic mortality.

Zooplankton, which are essential for the health and productivity of global marine ecosystems have suffered significant mortality and the impact has been observed at a range of 1,2km from the blasting sites.

Impacts include temporary and permanent hearing loss, abandonment of habitat, disruption of mating and feeding, and even beach strandings and death. For whales and dolphins, which rely on their hearing to find food, communicate, and reproduce, being able to hear is a life or death matter. Whales simply stop “talking” to each other.  

What safeguards does South Africa have in place to prevent harm to our marine life? The Mineral and Petroleum Resources Development Act 28 of 2002 affirms in its preamble the State’s obligation to protect the environment for the benefit of present and future generations, to ensure ecologically sustainable development of mineral and petroleum resources and to promote economic and social development.

On their website, PetroSA recognize the potential environmental impact that accompanies seismic surveys and states that no exploration can take place without the necessary permits, which in turn requires an environmental management programme (EMPR). An EMPR requires a full consultation with concerned parties and a comprehensive assessment of the environmental impact of the proposed activities.

There are also several mitigation methods that must be adhered to: no surveys are allowed within protected areas such as nature reserves and breeding colonies and buffer zones must be established around these delicate areas.

When surveys are carried out at night or when visibility is not optimal, the use of Passive Acoustic Monitoring is needed or else no surveys may be carried out.

Trained Marine Mammal Observers are also required to be on board the exploration vessels and they are required to scan the area for at least 30 minutes in order to determine if any mammals are close by. If so, the survey must be delayed. A soft – start procedure is also employed for at least 20 minutes to allow the marine mammals to move away from the area.

Any non – compliance with the EMPR is a violation in terms of the Mineral and Petroleum Resources Development Act 28 of 2002.

The Department of Environmental Affairs states that Operation Phakisa represents that new spirit of moving faster in meeting government’s targets. The government’s starting point was that South Africa is surrounded by a vast ocean with untapped resources. The oceans have the potential to contribute up to 177 billion rand to the gross domestic product (GDP) and create just over one million jobs by 2033. That said, the value of preserving our marine life for generations to come is equally important and our government would be failing in its duty if it did not adhere strictly to environmental stipulations as legislated.

Article by: Anisa Govender, senior associate in our Shipping Practice.