Geoscience and energy exploration industry body EnerGeo Alliance has said there is no evidence to suggest that seismic surveys are irreparably damaging to marine life.

Rather, it argued, seismic survey vessels often contribute to efforts to restore and recover marine life including by untangling animals that are trapped in nets.

Seismic surveys are a crucial part of energy source discovery, especially as the world moves to exploit more alternative energy sources which require seabed mining or natural gas extraction, for example.

Seismic surveys use sound to estimate the properties of the Earth’s subsurface from reflected seismic waves.

In a media briefing hosted on December 13, EnerGeo unpacked the process of seismic surveying and affirmed that geological scientists continuously research the effects of seismic surveys on marine life to understand and mitigate the impacts thereof.

EnerGeo scientific director and marine biologist Alex Loureiro said there were some situations where scientific literature was not necessarily representative of actual survey operations. For example, laboratory results often exaggerate the amount of time and proximity of exposure of hydrophones to animals, which are not applicable to realistic exposures throughout the course of a seismic survey.

She said there was sometimes the perception that, because seismic research is privately funded, it is tainted or influenced, but this is not the case, as industries want to understand the potential effects of activities and respect scientific integrity.

Responding to a question of why organisations would oppose seismic surveys if they are not damaging to the marine environment, Loureiro said there were cases where not enough information was being shared or not enough consultation was being undertaken by the parties involved.

“The impact of underwater noise is a global challenge, not just in South Africa. EnerGeo works with many stakeholders, including local fisheries, to proactively understand what are some of the risks in the area intended for exploration,” EnerGeo environmental consultant Ross Compton stated.

He shared a presentation showing how EnerGeo and its member companies span more than 50 countries and together advance the safe discovery, development and delivery of mainstay sources of energy, alternative energy and low-carbon energy solutions.

EnerGeo members include offshore and onshore survey operators, data providers and energy companies.

The principal role of the alliance is to work with regulators and other stakeholders in developing best practice guidance for the geoscience sector, based on best available science.

Compton said exploration is critical to meeting energy demand and that, with geophysical exploration, particularly seismic acquisition, the alliance makes sure safe, proven and efficient means are used to determine resource potential on land and offshore.

He explained that geophysical innovation has led to increased discoveries and that most data being collected at the moment is based on three-dimensional (3D) modelling, which uses historical two-dimensional (2D) data to target smaller areas for detailed mapping.

Compton said 3D mapping ultimately has a much smaller footprint, in the tens of kilometres, compared with 2D mapping spanning hundreds of kilometres.  

While seismic acquisition technology has been used worldwide for the last 100 years, more rapid advancements have been made in technology and processing in the last 50 years, with improved seabed imagery as a result.

Compton said a 3D seismic vessel is typically 100 m long and 30 m wide. The vessels travel at a speed of four to five knots while exploring. The ship crew involves 20 to 25 people while the seismic crew generally has between 25 and 30 people.

The EnerGeo environmental-impact assessment (EIA) guidance has been formulated with unique challenges of the seismic industry in mind and encompasses all aspects of the EIA process from preparation through to stakeholder engagement. It is designed to establish best practice for EIAs using seismic surveying globally.

Compton affirmed that the EIA process should include identification of affected resources, analysis of direct and indirect impacts on each resource and proposals towards mitigation to reduce impacts.

In this regard, stakeholder engagement was vital and needed to be tailored to groups of stakeholders appropriately.

Loureiro agreed, adding that stakeholders needed to access the resources through appropriate media and in ways that were comprehensible to them.

She stressed that seismic surveys always took unique considerations of the area into account, including breeding habits of rare species and seasonal factors.

Seismic surveys are also practically influenced by weather, human safety considerations with longer durations at sea and by costs and benefits of the exploration.

Loureiro said the detection of sound did not automatically mean impact on sound and responses to sound disturbance vary between all animals.

Responding to what seismic vessels do to help preserve marine life, Loureiro said there was an estimated 640 000 t of abandoned nets in the ocean worldwide, comprising 10% of marine litter.

The nets not only often entrap animals but also decompose into microplastics over time. The seismic vessels often remove the nets in the environments they operate in, as well as many of the 13-billion hooks, 900 000 fishing lines and 25-million lobster traps that are lost at sea every year.

Survey crews are also highly trained on best practice to assist entangled marine life, since animal specialists are not easily sourced in remote areas where seismic vessels regularly operate.

While many organisations have opposed the seismic surveying activity of oil and gas companies such as Shell, EnerGeo maintains that there is lack of evidence to suggest marine life is negatively impacted on by seismic acquisition that is done according to best practice.

Environmental organisation The Green Connection (TGC) regularly opposes activities that are aimed at finding and exploiting fossil fuels under the seabed, including seismic surveys, since many communities depend on the ocean for their livelihoods.

TGC is one of the organisations opposing the activities of Shell on South Africa’s Eastern Cape coastline.

The Eastern Cape High Court in September 2022 ruled that not enough is known about the cumulative impacts of seismic surveys and consequently found that government should not have granted an exploration right to Shell.

The High Court decided that the authorisation be set aside as there was no consultation with affected communities who live on the coastline and that stakeholder engagement was overall insufficient.

The appellants, including Shell and the Minister of Mineral Resources and Energy argued why they should be granted leave to appeal the High Court judgment in November 2022.

Exploration on the Wild Coast had been approved by the then Minister in 2014.

The matter has since been delayed until 2024.