Underwater Natural Heritage

Preserving the natural heritage of underwater ecosystems has become a prominent movement in society that has brought the diving community and scientific organizations closer together. This collaboration, also known as participatory science or citizen science, is aimed at promoting knowledge and preservation of biodiversity and habitats.

The "Natural Heritage" division within the CMAS scientific committee is dedicated to participating in scientific projects that manage knowledge about biodiversity through partnerships and alliances with public and private scientific organizations such as research institutes, naturalist networks, managers of natural areas, museums, and others. The goal is to share knowledge about plant and animal biodiversity and their ecosystems, so that society as a whole can take nature into account. This includes identifying and cataloging marine and freshwater species and habitats, invasive alien species, as well as protected or regulated species, and their temporal distribution.

Thanks to CMAS training in marine biology for divers, the committee has established a network of observers who can contribute to scientific programs and raise awareness among the diving community about the preservation of natural heritage.

Whale Shark

Whale Shark whale shark, (Rhincodon typus), gigantic but harmless shark (family Rhincodontidae) that is the largest living fish. Whale sharks are found in marine environments worldwide but mainly in tropical oceans. They make up the only species of the genus Rhincodon and are classified within the order Orectolobiformes, a group containing the carpet sharks.

Manta Ray

A manta ray swimming in the ocean Manta rays are large rays belonging to the genus Mobula (formerly its own genus Manta). The larger species, M. birostris, reaches 7 m (23 ft) in width, while the smaller, M. alfredi, reaches 5.5 m (18 ft). Both have triangular pectoral fins, horn-shaped cephalic fins and large, forward-facing mouths. They are classified among the Myliobatiformes (stingrays and relatives) and are placed in the family Myliobatidae (eagle rays). They have the largest brains and brain to body ratio of all fish, and can pass the mirror test.

Coral Reefs

Underwater Coral Reefs are underwater structures built by tiny sea animals. Their beautiful shapes and colors are a magnet for divers. They also provide an excellent home for thousands of marine creatures, including fish we love to eat.


Corals, anemones and jellies are related and all classified in the phylum Cnidaria or “stinging needles.” The animals in this group are aquatic, possess stinging cells within their tissues and have a body plan characterized by radial symmetry, which allows all parts of their bodies to be equally receptive and responsive to predator and prey. These animals have a single opening that serves as both the mouth and the anus. Tentacles with stinging structures
In biology, any group of fish that stay together for social reasons are shoaling, and if the group is swimming in the same direction in a coordinated manner, they are schooling. In common usage, the terms are sometimes used rather loosely. About one quarter of fish species shoal all their lives, and about one half shoal for part of their lives. Fish derive many benefits from shoaling behaviour including defence against predators (through better predator detection and by diluting the chance of individual capture), enhanced foraging success, and higher success in finding a mate. It is also likely that fish benefit from shoal membership

Pinna Nobilis

Pinna nobilis, whose common name is the noble pen shell or fan mussel, is a large species of Mediterranean clam, a marine bivalve mollusc in the family Pinnidae, the pen shells.  It reaches up to 120 cm (4 ft) of shell length. It produces a rare manganese-containing porphyrin protein known as pinnaglobin. The noble pen shell has been listed as an endangered species in the Mediterranean Sea. The European Council Habitats Directive 92/43/EEC, on conservation of natural habitats and the wild fauna and flora, proclaims that P. nobilis is strictly protected (by the Annex IV of EEC, 1992) – all forms of deliberate capture or killing of fan mussel specimens are prohibited by law.

Symbiotic Relationship

The symbiotic relationship between an anemone (Heteractis magnifica) and a clownfish (Amphiron ocellaris) is a classic example of two organisms benefiting the other; the anemone provides the clownfish with protection and shelter, while the clownfish provides the anemone nutrients in the form of waste. 

Sea Anemone

A typical sea anemone is a single polyp attached to a hard surface by its base, but some species live in soft sediment, and a few float near the surface of the water. The polyp has a columnar trunk topped by an oral disc with a ring of tentacles and a central mouth. The tentacles can be retracted inside the body cavity or expanded to catch passing prey. They are armed with cnidocytes (stinging cells). The picture was taken near a shipwreck in Cyprus.