February 19th 2025

Archipelagos Institute Participates in Greek Parliamentary Committee Discussion on Lionfish Population Control

The Archipelagos Institute of Marine Conservation recently took part in a session of the Greek Parliament’s Subcommittee on Water Resources, under the Special Standing Committee on Environmental Protection. The session focused on strategies for managing the population of lionfish (Pterois miles) in Greek and wider Mediterranean waters.

Dr. Anastasia Miliou, Research Director of the Archipelagos Institute, was invited as a speaker, bringing insights drawn from over 25 years of continuous presence and scientific monitoring in the Greek seas and the northeastern Mediterranean. Archipelagos’ work includes research conducted at dozens of monitoring stations throughout the Aegean and close collaboration with local fishing communities and coastal societies.

Invasive Species: A Growing Threat

In discussing invasive species, Dr. Miliou highlighted a striking point: archaeological evidence from an Aegean cave inhabited 3,500 years ago shows that people were consuming nearly the same fish species as we do today. However, in just the past few decades, this balance has shifted dramatically. More than 1,000 alien species have been recorded in the Mediterranean, with over 650 having established stable populations, and more than 100 considered invasive, meaning they pose significant threats to biodiversity and ecosystem services.

While the migration of marine species is not a new phenomenon—it has occurred for thousands of years—the current scale of the issue is clearly driven by human activity, in addition to climate change. Key contributors include:

• The expansion and deepening of the Suez Canal, carried out without appropriate ecological safeguards or management plans.

• Ballast water discharge from international shipping, which continues despite existing international regulations. Thousands of tons of ballast water—along with the marine organisms it contains—are released into the Mediterranean from distant seas due to the lack of enforcement and infrastructure. This problem could be mitigated, as seen in regions like the Persian Gulf, where ships are required to exchange their ballast water before entering sensitive marine areas.

All of these are manageable challenges—if there is political will and real interest in addressing them.

The Bigger Picture: More Than Just the Lionfish

While lionfish deserve attention and tailored management, it’s essential to look beyond the species itself and focus on root causes, not just reactive measures. Climate change, invasive species, and inadequate prevention strategies must be addressed in an integrated manner.

One critical aspect largely absent from the committee’s discussion was overfishing. Even the two most problematic invasive species in the region—lionfish and pufferfish (Lagocephalus)—have natural predators among native fish species, especially in their juvenile stages. Healthy populations of native predators can serve as natural control mechanisms against invasive species and even jellyfish blooms.

For example, in a recent study, a predatory fish (known locally as “kynigos”) was found to have dozens of juvenile pufferfish in its stomach, demonstrating the potential of a balanced ecosystem.

However, ongoing overfishing in Greek waters continues to deplete native fish stocks, dismantling these natural defences. For years, Greece has neglected its fisheries sector, failing or refusing to implement effective management strategies. The result is the alarming decline of fish populations, the degradation of coastal livelihoods, and the erosion of marine ecosystem resilience.

Effective fisheries management and the reversal of overfishing must be a top national priority, even if decades overdue.

Targeted Lionfish Fishing: Helpful or Harmful?

While the committee explored possible measures to reduce the lionfish population, such as promoting targeted fishing, there is a danger that such efforts could become short-term, superficial solutions. For example, encouraging targeted lionfish fishing may help locally and temporarily, but it carries the risk of encouraging further overfishing, especially in a country with over 16,000 kilometres of coastline and thousands of islands and islets.

No matter how many fishing programs are subsidised, the problem will persist and worsen unless the underlying causes are addressed.

The Time for Action Is Now

There is no more time for theoretical discussions and inaction. Greece must finally adopt concrete, science-based measures to protect its seas. Only by doing so can we begin to effectively address challenges like the spread of invasive species and restore the balance of marine ecosystems.