Overtourism and decades of intensive agriculture have resulted in the shocking sight of thousands of dead fish washing up on the shore at the biggest coastal lagoon in the western Mediterranean.

The 90km-long saltwater lagoon at Mar Menor in Murcia, Spain, is protected by a string of international conservation conventions and under EU nature and water laws the Spanish authorities are under obligation to protect and restore it.

Thousands of different species – including the only remaining world population of Pinna nobbilis, a large Mediterranean clam – were killed when the water body became toxic due to a sudden surge in sulphides – a relatively rare natural phenomenon.

But, marine life couldn’t cope with this natural event as the lagoon was so oxygen-depleted which caused them to – quite literally – rush to the surface to take their last breath.

Julia Martinez Fernandez, Executive Director of the New Water Culture Foundation, told META that NGOs have warned authorities of Mar Menor’s brewing “ecological collapse” for decades due to the “severe eutrophication caused by intensive irrigated agriculture”.

Eutrophication is a process linked to fertiliser run-off from intensive agriculture which lead to uncontrolled growth in plants and algae, depriving other life of oxygen.

Tourism has also put additional pressure on the lagoon. Infrastructure like ports for watersports and yachting, seafront promenades, and artificial beaches have all altered the lagoon’s natural processes.

Martinez Fernandez said that NGOs reported the dire situation in Mar Menor in 2016, 2017, and 2018 to the European Parliament Petitions committee.

The Murcia government has repeatedly claimed that the situation is under control.

According to the European Environment Agency (EEA), pressures such as pollution from agriculture and industry, over-abstraction, and hydropower have all rendered the majority of Europe’s rivers, lakes and coasts are unable to adequately support wildlife and provide the vital unsung contributions they make to communities such as flood protection. Only 40% of EU rivers, lakes and wetlands are in a healthy state.

Sergiy Moroz from the European Environmental Bureau said:

“The EU already has ground-breaking water laws in place to prevent incidents such as the horrendous death of marine life we have seen this week in Mar Minor, but these laws have not been properly implemented and enforced.”

Over 130 NGOs have backed the law, stating that it is essential to keep rules designed to protect and restore rivers, lakes, wetlets and other water environments.

Following a review of the EU’s water law this year, the new European Commission will decide on its future in early 2020. In March, 375,000 people called for the law to be upheld and for EU governments to properly implement and enforce it instead by taking action when there are clear breaches of the law.