Art / Documentaire

This documentary traces the implementation of a marine scientific program on invasive plants in the Mediterranean Sea. 


Plastics, invasive algae, posidonia are frequently associated with the Mediterranean, a space almost always threatened by human action, even more so at a time of tourist saturation. The sea suffers, but it has some notable allies. Scientists based in Mallorca are always vigilant in detecting anomalies and sounding the alarm.

IMEDEA scientist Fiona Tomas campaigned on Cabrera this week collecting samples of invasive algae, her area of research. Of particular concern is the introduction of Halimeda incrassata. “It is a dangerous species. It is capable of smothering posidonia, which is an endemic species of the Mediterranean. It is capable of enveloping a nacre and smothering it. We think it has a tropical origin,” says Fiona Tomas.

An anchor or an invasive algae, which of them is more harmful to seagrass? “It’s different. The anchor causes a very strong, very local impact that results in very high immediate mortality. With invasive algae, the mortality is slower, but the impact is multiple. They weaken you and the ability to recover decreases a lot. An anchor, at least, we can regulate it,” says the scientist.


The sea has extraordinary connectivity. Species that pass through the Suez Canal from the Red Sea can end up settling in the Balearic Sea, with traumatic and irreversible consequences for an ecosystem as fragile as the marine environment. “The big problem with invasive species is that by the time you detect them, they have already established themselves. Eradication is impossible, and it’s also very expensive,” laments Fiona Tomas.


The researcher calls for greater public awareness. “People need to know that if they drop anchor in Sicily, they can introduce an invader into the system when they return to Majorca. It is prevention that makes the difference,” warns the researcher, who invites people to visit, an informative project that offers guidelines to identify these algae and prevent their expansion.