April 2026

Marine life in the Mediterranean is under immediate threat from seismic surveys and hydrocarbon drilling

A new scientific study reveals the serious threats facing marine mammals due to oil and gas extraction activities near Marine Protected Areas (MPAs) in the Mediterranean, including Greece.

The article, published this month in the prestigious scientific journal “Ethics in Science and Environmental Politics” by distinguished marine biologists from around the world, demonstrates that the impacts on marine “megafauna” (particularly on whales and dolphins) from seismic surveys and hydrocarbon extraction are numerous and catastrophic and include physical injuries (e.g., hearing damage, chronic stress, hormonal changes), behavioral changes (e.g., changes in feeding and resting patterns), as well as potential cetacean strandings and deaths.

Seismic surveys, which are initially conducted to map the seabed prior to the implementation of oil and gas extraction projects, require the use of so-called air guns that produce extremely loud low-frequency sounds with a range of up to 4,000 kilometers. Cetaceans’ navigation, communication, foraging, and overall survival literally depend on sound. Furthermore, the displacement of populations from their habitat is a highly problematic scenario, since species such as the fin whale avoid noisy areas for days on end.

As a result, this process is one of the most harmful and dangerous activities for marine life, as the sounds it produces are among the loudest in the ocean—louder than any known biological sound.

The formal complaint to the European Commission

Two of the three cases examined in the report are the subject of pending legal proceedings initiated by ClientEarth, WWF Greece, and Greenpeace Greece. The three organizations filed a formal complaint with the European Commission in 2023, pointing out that oil and natural gas exploration and exploitation projects were being approved in the ecologically significant area of the Hellenic Trench, in close proximity to protected areas, despite the clear risks they pose to marine species and in violation of EU nature protection law.

Francesco Maletto, a lawyer at ClientEarth, said: “The devastating impact of fossil fuels on the climate is widely known, especially in Greece. However, this new research reveals the scale at which this industry is wreaking havoc on ecosystems at every level. The Hellenic Trench is one of the most biodiverse regions in the entire Mediterranean. Yet, the widespread noise caused by hydrocarbon exploration and extraction is devastating for marine mammals. Will the Commission stand idly by while this happens—in direct violation of EU law—or will it intervene to protect some of Europe’s most endangered marine species?”

Anna Vafeiadou, head of the legal department at WWF Greece, stated: “Greece’s seas are still among the healthiest in Europe, precisely because of the absence of destructive activities such as oil and gas drilling. We are sleepwalking toward an environmental disaster if these drilling plans go ahead. This scientific article published today highlights the serious risks to our seas and marine life posed by oil and gas projects. The science is clear: the measures that can be taken to mitigate the impacts of hydrocarbon exploration on the unique ecosystem of the Hellenic Trench are limited. We call on the European Commission to intervene and ensure the enforcement of European legislation before irreparable damage is caused.”

Costas Kaloudis, climate and energy campaigner at Greenpeace’s Greece, stated: “With 20% of Greece’s marine areas having been allocated for hydrocarbon exploration and an extremely weak institutional framework for protecting the marine environment, the future of the marine mammals we are trying to protect looks bleak. The Greek government’s promises of thorough procedures to prevent environmental damage and ensure that marine mammals are not negatively affected by hydrocarbon exploration and drilling appear to have fallen on deaf ears. It is time for the European Commission to step up pressure on the Greek authorities: future generations should also be able to enjoy thriving biodiversity in Greek waters.”

EU environmental legislation requires Greek authorities to fully assess the impact that such activities will have on threatened marine biodiversity in protected areas before giving the green light for their implementation. This scientific publication confirms the arguments put forward in the complaint: that the assessments for projects approved in the Mediterranean were inadequate and did not rely on the best available scientific knowledge, as required by EU law.

This publication raises critical questions regarding the validity of the findings that led to the approval of the projects, which appears to have been based on outdated, incomplete, and inaccurate data. It was also found that the assessments underestimated the serious risks posed by activities such as seismic surveys to endangered species, such as fin whales, based on unscientific assumptions, such as that the animals would simply “move away” from the source of the noise.

Following this publication, the three organizations reiterate their call on the European Commission to take action against the widespread violations of EU nature conservation legislation in the region.

Notes to editors:

The scientific study:

  • The article refers to research that demonstrated that low-frequency sound from seismic surveys can propagate across entire ocean basins and travel distances of up to 4,000 km (Castellote et al. 2012, Nieukirk et al. 2012).
  • Inadequate mitigation measures: The article also showed that a series of inadequate mitigation measures were taken during the seismic surveys. These included the decision to conduct seismic surveys during the winter in order to avoid impacts on the “reproductive processes” of cetaceans. However, the report found that despite these measures, a serious incident of mass stranding of three porpoises occurred during the surveys, 10 km from the Ionian Sea extraction field, a fact not mentioned in the environmental assessment.

Biodiversity and the local context:

  • The entire Hellenic Trench and the adjacent Ionian Archipelago are “areas of high biodiversity concentration” and key habitats for many endangered whale species (including pilot whales and the endangered Mediterranean bottlenose whales), as well as the loggerhead sea turtle (Caretta caretta) and the Mediterranean monk seal. For these reasons, they have also been designated as Important Marine Mammal Areas (IMMAs) by the International Union for Conservation of Nature (IUCN).
  • Human-induced noise has been linked to numerous strandings and dolphin deaths in the past. The study refers to seven known mass strandings during the 1990s, as well as the stranding of three porpoises in Corfu in February 2022, an unusual event that occurred while seismic surveys were being conducted in the area.
  • Noise from seismic surveys is not the only threat posed by the oil and gas industry to marine megafauna in the Mediterranean. From increased noise and shipping traffic to extraction activities, chronic toxic pollution, and the installation and decommissioning of infrastructure, these activities contribute to chronic, cumulative, and multi-level stressors and pressures, and exacerbate the pre-existing impacts of overfishing, climate change, and pollutants. The study argues that the impact of seismic surveys must be considered within this broader context.

The complaint:

  • The organizations ClientEarth, WWF Greece, and  Greenpeace Greece Greek  initially sent a letter to the European Commission in December 2023, requesting the initiation of infringement proceedings against Greece. The European Commission confirmed in late 2024 that it would proceed with an investigation.
  • View the map showing the new potential drilling sites here.
  • In their latest letter (April 2026), the organizations highlighted the findings of the new study regarding the inadequacy of impact assessments and compliance measures and, furthermore, in light of the ongoing expansion of offshore oil and gas activities in the region, reiterated the need for the Commission to take compliance measures against these systemic violations of EU law by the Greek authorities.
    • The concession contracts for four new mining fields located south of the Peloponnese and south of Crete have now been ratified by the Greek Parliament under Law 5287/2026. The report’s findings regarding shortcomings in the environmental impact assessment raise further concerns among the complainants that the new activities will be carried out in the same flawed manner as those covered in their complaint.
  • The multinational fossil fuel company Chevron and the Greek firm HELLENiQ Energy have officially expressed their interest in opening additional fields for oil and gas operations, and the Greek Ministry of Environment and Energy has accepted this, initiating the process for formal licensing. Chevron is the second-largest private hydrocarbon company in the world, headquartered in the U.S. and operating in more than 180 countries
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