Seagrasses, also call Thalassia Prairies, are distributed throughout all the Caribbean Sea. There are seven species in this ecosystem of which Turtle grass (Thalassia testudinum) is the most common. Thalassia Grasslands develop in the gaps formed between coral reefs and sandy beach or in low of more protected areas such as bays or estuaries. Require for their development of soft or muddy soil, clear sea water without sediment, salinity ranging between 20 to 45 parts per million, be proteguidas from direct wave action, they can be developed to depths of 20 m, reproduce by rhizomes and are very delicate in their root system and its deterioration completely stops their growth.

In the sandy bottoms in the Thalassia Prairies the patches can be larger or smaller and with other benthic algae provide shelter for many marine species of fish, mollusks as the great Botuto, crustaceans such as lobsters, sponges, etc. and even the Green Tortoise and Hawksbill turtle.

Thalassia Grasslands maintain many species of herbivorous animals such as the manatee (Trichechus manatus), Green Tortoise (Chelonia mydas), parot fish (Sparisoma radians).

Among the many resident species and visitors of the Thalassia (Strombus gigas), la Ceritia de la hierba (Bittiolum varium), and the Starfish (Oreaster reticulatus).

The white urchins (Tripneustes ventricosus) and the long spines (Diadema antillarum) with fire coral .

On the other hand, the greatest diversity of wildlife is found in the tiny plankton in suspension, whith the dominant dinoflagellates which often exhibit the phenomenon of luminescence, night show at the sea of ​​unforgettable beauty where any movement of the sea this is lit with the phosphorescence of these organisms.

Reference: Playa Arenosa, Dunas y Praderas de Yerbas Marinas