The Balearic Islands record an overall improvement in the state of posidonia in 2025

The Department highlights that sites in a “deficient” or “poor” condition have dropped from 25% in 2023 to 17% in 2025.

During 2026, monitoring will be strengthened at sites with less favorable results, and temperature data will be completed to assess the impact of heatwaves.

The Government has released the results of the 2025 campaign of the Balearic Islands Posidonia Monitoring Network (Red Posidonia), which show a largely stable situation and an improvement in the condition of Posidonia oceanica meadows across the archipelago, confirming the effectiveness of continuous scientific monitoring. It should be noted that Red Posidonia, a project of the Species Protection Service of the Department of Agriculture, Fisheries and Natural Environment, carried out by Tragsatec, aims primarily to determine the conservation status of the meadows and analyze their long-term evolution using consistent scientific indicators.

Monitoring is carried out with the participation of various partner organizations and volunteer divers. In 2025, data were collected at 34 of the 46 stations that make up the network, distributed throughout the archipelago. At each site, the density of leaves per square meter, microcoverage, linear coverage of living posidonia, the proportion of dead posidonia, the presence of invasive algae, and water temperature through continuous recordings were analyzed.
Fifty-six percent of the analyzed sites were classified as being in “good” or “very good” condition, 27% as “moderate,” and the remaining 17% as “deficient” or “poor.” In 2024, this “deficient” or “poor” percentage was 21%, while in 2023 it was 25%, demonstrating the positive trend in the condition of the meadows.

Overall, the data reveal that stability or increases in posidonia microcoverage and density predominate at stations shallower than 25 meters, although at deeper stations density decreased in 40% of cases. Linear coverage, which reflects posidonia cover on a larger scale, showed negative trends at only 15% of study sites and remained stable elsewhere.

In this regard, Minister Joan Simonet highlighted that “the 2025 data confirm that almost six out of ten stations show a good or very good conservation status and that, at most sites, posidonia remains stable or improves on a small scale. In addition, the percentage in poor condition has also decreased.”

The minister emphasized that sites with negative trends help identify priority areas for action: “We will continue working to consolidate the trend of stability and improvement of the meadows across the Balearic Islands, with rigorous scientific monitoring to ensure the conservation and protection of one of the main environmental assets of our archipelago,” he stressed.

Another positive aspect is that the frequency and diversity of invasive algae continue to decline. The species Caulerpa cylindracea, common in previous years, was detected at only one sampling point. As for flowering, seven inflorescences were located sporadically, all in Ibiza during October.

On the other hand, water temperature records at the stations in June and July 2025 exceeded those of 2023 and 2024. However, data for August are not yet available, the month when the most intense marine heatwaves can occur. This information will be completed next year.

As in previous years, monitoring also included 18 additional points of particularly degraded meadows in southwest Ibiza, assessed by the Marine Area of GEN-GOB since 2019 using an equivalent methodology. Temporal trends at these stations were more unfavorable, although stability still predominates.

At these points, 44% are in “moderate” condition and the remaining 56% in “deficient” or “poor” condition. At deeper stations, maximum density decreased in 40% of cases, while microcoverage remained stable or increased. In general, above 25 meters depth, posidonia remains stable or increases on a small scale, while at larger scales it remains stable with occasional declines. This monitoring in these specific areas provides detailed information to guide recovery and management policies.

In 2025, a total of seven volunteer diving clubs and centers took part, with 78 participants including divers, boat skippers, and organizers. Around twenty organizations and administrations also collaborated: the Menorca Socio-environmental Observatory; the Marine Area of GEN-GOB (funded by the Sant Josep de Sa Talaia Town Council and IbizaPreservation); the Government’s Posidonia Surveillance Service; Aquadiving (funded by the Santa Eulària des Riu Town Council); Anfibios (funded by the Sant Josep de Sa Talaia Town Council); the Ministry for the Ecological Transition and the Demographic Challenge’s Service for Conservation Actions, Marine Knowledge Improvement and Environmental Protection of Marine Habitats, Species and Protected Marine Areas; Salvem sa Badia de Portmany; Calvià Town Council; and the Llevant de Mallorca Marine Reserve – Cala Rajada (managed by the General Secretariat for Fisheries of the Ministry of Agriculture, Fisheries and Food and the Government’s Directorate-General for Fisheries).