AN analysis has shown that a one-off pollution spill was not to blame for the death of thousands of fish and crustaceans in the Mar Menor.
On October 12 the beaches of Villanitos and La Mota (Lo Pagán) were covered in dead marine life, with three tons of fish having to be cleared away.
Initially it was feared that a spillage might have caused the environmental disaster but tests ordered by the Public Prosecutor have shown that it was caused by a lack of oxygen in the water.
The samples, which were taken by the Nature Protection Service of the Guardia Civil (Seprona) and environmental agents of the Confederación Hidrográfica del Segura, and analysed in the Laboratory of the Water Quality Area of the CHS, contain low levels of pesticides and metals-.
However, the CHS report draws attention to the reduced value of dissolved oxygen in water (less than one microgram per litre) and elevated levels of sulfides (6.5 mg/l). Sulfur acts to remove the oxygen dissolved in water in order to convert it into sulphate.
“The low concentration of dissolved oxygen in the waters is one of the most common causes of episodes of fish mortality that can occur in both marine and continental waters. So, and in view of the results, we have determined this is what happened in the episode observed on October 12, 2019 in the area,” says the CHS report.
The thousands of fish and crustaceans that came out of the water in Lo Pagán in search of oxygen last October 12 are just a reflection of the desert that the Mar Menor has become. A report by the Spanish Institute of Oceanography (IEO) commissioned by the Ministry for Ecological Transition states that the mortality of fish and crustaceans did not occur only on the beaches of Villanitos and La Mota, but in large areas of the lagoon.
IEO scientists found in a series of dives from September 25 a “massive mortality of species and populations of the lagoon bottoms greater than three to four metres”, which represents 80 per cent of the wetland.
In other words, the Mar Menor was already a fish cemetery before the images and videos that were flashed round the world were taken.
The environmental problems in the Mar Menor have become of increasing concern to the local population. Recently 55,000 people joined a demonstration in Cartagena calling for urgent measures to stop agricultural runoff and other pollution.