Maërl subtidal beds are big vegetable formations composed of an accumulation of calcareous red algae which grow slowly and have no subjection to the substrate. These algae form an ecosystem of high ecological value, and are home to a wide variety of organisms, both plant and animals, which use them as refuge and breeding area, some of them being of high interest. This makes it one of the most productive ecosystems on the coast of Spain.

Maërl subtidal beds grow mostly in areas where there is an important flow of tides and currents, or where wave action is strong enough to take and remove fine sediments, but not enough to break algae interlocking branches. In the case of the Galician Rias, maërl subtidal beds are vital to the ecological balance of marine ecosystems, as well as for the local economy of fish and shellfish.

Maërl is protected under Appendix I of the Habitats Directive. Furthermore, two of the species that form these meadows, Lithothamnium corallioides and Phymatolithon calcareum, are listed in Annex V of that directive. This submarine community is also included in the Nature Network 2000.

Watch the final report in PDF format:

Informe sobre la experiencia (IN SPANISH) [Size 460 kb]