Coral reefs are home to 1/4 of all marine species,
and are vital to 275 million people in the world.
In these labyrinths of living limestone, scientists estimate that more than a million animal and plant species are associated with them and that they are home to more than 25% of all marine life.
They are also the basis for the formation of other ecosystems. In fact, the grazing of coral formations by hordes of parrotfish leads to the formation of very large expanses of sand; this, through the action of currents, leads to the formation of shallows, islands and above all, in favourable areas, to the formation of mangroves and other coastal forests.
Reefs occupy only a tiny part of the seabed: less than 0.2%. Yet they are found along more than 150,000 kilometers of coastline in more than 100 countries and territories.
Due to their massive formation between the surface and the first few dozen meters of depth, coral reefs form a barrier that absorbs the elements coming from the open sea in a very efficient way.
They absorb wave energy and contribute to the reduction of coastal erosion. They reduce damage in the event of storms, hurricanes and other cyclones, as well as, to some extent, the energy of tsunamis. In doing so, they protect both the ecosystems between the reefs and the coasts, such as lagoons with sea grass beds, as well as human settlements along the coast.
Their action is so effective that man imitates it by immersing concrete structures along some of our fragile coasts. Without this protective role, some countries located in atolls would no longer exist.
More than 275 million people live within 10 kilometers of a coastline and less than 30 kilometers from reefs. One eighth of the world’s population, about 850 million people, live within 100 kilometers of reefs and are likely to benefit from the ecosystem services provided by reefs.
A large proportion of these human populations live in developing countries and island nations and therefore depend to a large extent on food taken directly from reef waters and thus depend on the direct and indirect means of subsistence they can derive from them.
Reef animals are an important source of protein. Coral reefs provide about 10% of the fish caught worldwide. But this figure rises to 20-25% in developing countries, and 70-90% in Southeast Asian countries.
“Well-managed” reefs can yield between 5 and 15 tons of fish, crustaceans, molluscs and other invertebrates per square kilometer.
As a result of direct revenues from fishing, reefs provide a resource and services that are worth billions of dollars each year.
Millions of people around the world depend on reefs for food, protection and employment. These figures are all the more impressive because reefs cover around 1% of the earth’s surface.
According to an estimate, the total annual net benefit of the world’s coral reefs is $29.8 billion.
Tourism and recreation account for $9.6 billion, coastal protection for $9 billion, fisheries for $5.7 billion and biodiversity for $5.5 billion (Cesar, Burke and Pet-Soede, 2003).
Reefs are often the backbone of tropical regions’ economies, where they are generally located.
They attract divers, freedivers, recreational fishermen and lovers of white sandy beaches. More than 100 countries benefit from reef-related tourism and it contributes to more than 30% of export earnings in more than 20 countries.
Local economies benefit from billions of dollars, from visitors that come to admire their reefs to companies exploiting reef ecosystems. In many small islands, more than 90% of new economic development depends on this coastal tourism.
Reef tourism, if managed in a sustainable manner, i.e. respectful of reefs by limiting the destruction and pollution induced by this same tourism, especially when it comes to mass tourism, can provide alternative or complementary income resources for coastal communities in developing countries.
Deprived to a very large extent of any possibility of movement, corals have developed an arsenal of very effective chemical weapons to defend themselves and fight in the conquest of reef space.
Coral organisms are of great interest in the search for treatments for certain cancers or the aging of cells. Moreover, due to its nature that is very similar to our bones, the coral’s skeleton, used since 1970 for bone grafts, is a promising lead for bone regeneration.
Since only an infinitesimal portion of reef organisms have been sampled, analyzed and tested, the potential for new pharmaceutical discoveries is enormous.