Sant Josep de sa Talaia has completed a new round of scientific monitoring of Posidonia oceanica meadows around es Vedrà and the Freus between Ibiza and Formentera, as part of the Balearic Islands' Posidonia Monitoring Network.

The latest fieldwork took place on September 25 and 26, with 18 volunteers and technical staff collecting data at monitoring stations near es Vedrà and the islet of es Caragoler.

Monitoring the health of the seagrass

The Posidonia Monitoring Network, promoted by the Balearic Government, carries out annual surveys to track how Posidonia oceanica meadows change over time.

At each monitoring station, researchers and volunteers examine several indicators of the condition of the meadows. These include the density of Posidonia shoots per square metre and the coverage of the seabed, together with the presence of flowers and fruit, invasive species and noble pen shells, or nacra.

The programme is designed to provide consistent scientific data that can be compared over time and used to identify changes in the conservation status of the meadows.

Seven monitoring stations funded by Sant Josep

The latest campaign covered two official monitoring stations located at es Vedrà and near es Caragoler.

Sant Josep also finances monitoring at five additional stations across its coastline: sa Xanga, Porroig, Cap Llentrisca, Cala d'Hort and Conillera.

The additional monitoring is carried out in collaboration with the GEN-GOB Marine Area, extending the amount of information available about Posidonia along the municipality's coastline.

Other organisations also contribute to monitoring the wider network. Salvem sa Badia and IbizaPreservation support work at stations in Cala Bassa and Cala Vedella.

The municipality covers the diving equipment and maritime resources required for the monitoring campaigns at the stations it supports. The September fieldwork also involved the diving centres Orcasub in Cala Tarida and Anfibios in Platja d'en Bossa.

What the latest results show

The September fieldwork produced new data, but Sant Josep has not yet published the results from these latest dives.

The most recent published results from the Balearic Government cover the 2025 monitoring campaign. Those results showed that 56% of the monitored points were classified as being in good or very good condition, 27% were considered moderate and 17% were classified as deficient or poor.

The 2025 results represented an improvement in the proportion of points classified as deficient or poor, which fell from 25% in 2023 to 21% in 2024 and 17% in 2025. The Government described the overall condition of the meadows across the Balearic Islands as largely stable or improving.

However, the regional data also showed areas requiring continued attention. At deeper stations, Posidonia density decreased in 40% of cases, while additional monitoring of particularly degraded meadows in southwest Ibiza found 56% of those points in deficient or poor condition.

Monitoring remains important as sea temperatures rise

The Balearic Government has also highlighted water temperature as an important factor in the ongoing monitoring programme.

The 2025 records from June and July showed higher water temperatures than in 2023 and 2024. The Government noted that additional temperature information was still required, particularly for August, when marine heatwaves can be more intense.

The 2026 monitoring programme is therefore intended not only to track the condition of Posidonia meadows but also to build a longer-term dataset that can help scientists identify areas showing deterioration or improvement.

Why Posidonia matters to Ibiza

Posidonia oceanica is a Mediterranean seagrass species that plays an important role in marine biodiversity and coastal ecosystems.

The Balearic Government's monitoring network was established to assess the conservation status of these meadows and their long-term evolution, while also raising awareness of the importance of protecting them.

The waters around es Vedrà form part of the protected natural area of the Reserves Naturals des Vedrà, es Vedranell i els illots de Ponent, where Posidonia meadows are among the marine habitats found in the reserve.

For Sant Josep, continuing the monitoring programme provides a way to track the condition of these important underwater habitats across different parts of the municipality and identify areas where further conservation work may be needed.

The September campaign is now complete, with the newly collected data expected to contribute to the continuing scientific assessment of Posidonia in Ibiza's waters.