efe-epaValencia (Spain)

The European Union on Monday proposed using a species of sea turtle as an indicator of the level of environmental pollution in the Mediterranean Sea based on research conducted by a Spanish university.

The EU's Marine Strategy Framework Directive draws on the long-term study conducted by the Marine Zoology Unit (UZM) at the Cavanilles Institute of Biodiversity and Evolutionary Biology of the University of Valencia – located in the eastern Spanish port city of the same name – that analyzes the plastic waste ingested by loggerhead sea turtles (Caretta caretta).

"The consideration of the loggerhead turtle as omnivorous, which implies a higher probability of ingesting waste, makes this species an excellent candidate to monitor sea litter," read a statement by the university.

"This species feeds on many invertebrates and vertebrates such as jellyfish, pelagic tunicates and different fishes and cephalopods rejected by fishermen," it quoted UZM researcher Jesús Tomás as saying. "Almost any element found in the water column can be considered as a potential prey for the loggerhead turtle, including, of course, floating waste."

The latest data collected by the research team showed that the turtles' intake of macroplastics has slightly dropped over the last decade along the coast of the Valencia region.

"This could be caused by a change in their habitat and diet – since they have started to frequent coastal zones – rather than a real decrease of sea waste," explained Frances Doménech, who authored an article published in the scientific journal Environmental Pollution.

The UZM painstakingly counted the levels of waste material ingested by hundreds of loggerhead turtles that were captured over a period of 20 years (1995-2016) in order to obtain the figures that the EU was now set to use as a pollution indicator through an amendment to the Marine Directive, which was first adopted by the European Commission in 2008.

"The Directive enshrines in a legislative framework the ecosystem approach to the management of human activities having an impact on the marine environment, integrating the concepts of environmental protection and sustainable use," the Commission said on its website.

With the aim of improving the environmental health of the European seas, the Directive urges member states to develop an up-to-date strategy to deal with threats such as plastic waste.

Crucially, this involves an accurate assessment and monitoring of the actual pollution levels of the continent's marine waters; which is why the bloc has decided to try out the revolutionary approach of using sea turtles for this task.

Plastic waste derived from human activity is, unquestionably, one of the main threats to marine ecosystems throughout the planet.

Sea turtles often ingest plastic that they mistake for food, which can lead to severe health problems, since the waste often blocks or damages their digestive systems, causing a painful death.