Scuba Dive Volunteers Needed for Marine Conservation Project

Posidonia oceanica is the world's oldest living organism. One seagrass meadow, formed by the process of cloning and classed as one organisim, was recently dated at between 80,000 and 200,000 years of age.

Posidonia oceanica, a habitat unique to the Mediterranean Sea, is a protected species and Posidonia beds are identified as a priority habitat for conservation under the European Union's Habitats Directive (Dir 92/43/CEE) as the seagrass meadows are a vital breeding and feeding habitat for hundreds of different species of fish and marine invertebrates.

In Catalunya trawler fishing over seagrass beds was banned many years ago. However, Posidonia oceanica faces many threats to its survival due to the growing pressures placed upon Mediterranean coastal ecosystems from development and tourism. As the Posidonia meadows are being destroyed the Posidonia pipefish, relative of the seahorse and so perfectly adapted to its habitat, is becoming harder to find.

The Posidonia pipefish, Syngnathus typhle, has evolved to perfectly resemble a blade of Posidonia seagrass. It is so well camouflaged that it is virtually impossible to see unless it happens to swim above or outside the seagrass beds, which is a rare occurrence. It is a poor swimmer and rarely ventures out of the safety of the Posidonia meadows, spending it's time head down within the Posidonia shoots searching for tiny shrimps to eat. It is totally dependent on this habitat for daily food and shelter, and as a seasonal breeding ground and nursery.

In Cala Montgó on the Costa Brava, where we have been diving and carrying out research for the past 12 years, we have witnessed an estimated 25% loss of Posidonia beds, mainly as a result of unregulated anchoring by pleasure boats each summer. Where there were once lush meadows of Posidonia teaming with marine life, we now see barren sediment, often littered with trash from tourist boats.

Without the presence of Posidonia oceanica we would not have the biodiversity that attracts hundreds of divers and snorkelers to L'Escala each year. Cala Montgó was included within the "protected zone" of the Medes Islands and Montgri coast two years ago but still no regulations have been agreed to provide practical protection for this important threatened species.

Petition:

We, the undersigned, wish to express our concern with the lack of regulations to protect Posidonia oceanica in Cala Montgó.

The continued uncontrolled anchoring by pleasure craft threatens this priority habitat and the biodiversity that it supports.

We therefore ask that regulations be introduced to prohibit anchoring over the Posidonia beds in Cala Montgó, and that anchoring be restricted to a designated area well away from the surviving seagrass beds.

Protect Posidonia! Sign our Petition.

Posidonia oceanica (L.) Delile is a seagrass species endemic to the Mediterranean Sea that forms dense and extensive underwater meadows with leaves that can attain 1 metre in height. These meadows provide important ecological functions and services and support a highly diverse community, including species of economic interest.

Over the last few decades, following increased coastal urbanisation and industrialisation; many P. oceanica meadows have disappeared. It is estimated that 46% of the underwater meadows in the Mediterranean have experienced some reduction in range, density and/or coverage, and 20% have severely regressed since the 1970s. P. oceanica beds are identified as a priority habitat for conservation under the European Union's Habitats Directive (Dir 92/43/CEE).

Current main threats to the habitat include: water and sediment nutrient enrichment (eutrophication), the disruption of the sedimentation/erosion balance along the coast and direct destruction by human modifications of the coastline, degradation by boat trawling and anchoring, salinity increase in the vicinity of water desalination facilities and the proliferation of invasive algal species.

Conservation management is mainly focused on protection from physical damage through the installation of artificial reefs and seagrass-friendly moorings for boats, which reduce the erosive pressure of otter-trawling and free anchoring in shallow meadows. The control of invasive species (Caulerpa taxifolia, C. racemosa) has also been performed recurrently in some P. oceanica beds.

There is a need to further develop regulations for activities that have a negative impact on P. oceanica beds (e.g. pollutants level limits and allowed minimum distances of impact sources to meadows) and to implement them through a vigilance system that is coordinated with the existing seagrass monitoring networks.

For more information read my articles on the Marbef Wiki:
http://www.marbef.org/wiki/Mediterranean_seagrass_ecosystem
http://www.marbef.org/wiki/Posidonia_oceanica_%28Linnaeus%29_Delile