How are coral reefs created?
Polynesian islands are born of a series of under water gigantic volcanic eruptions. Each island was originally created by a “hot spot” located just below the earth’s crust.
Regularly, at a range of several million years, the hot spot comes to life and creates a news volcano that shoots through the ocean’s surface and becomes, once extinct, a high rising island. The presence of these new supports in waters, gathering all the necessary conditions for life, allows the reef to grow.
As the millenniums go by, the high rising island slowly sinks in the ocean because of its own weight while it is eroded by the rain and wind. In the mean time, the coral reef that surrounds it is still growing. The deeper the island sinks, the larger the lagoon grows.
Ultimately, the volcanic tip of the island vanishes under the ocean’s surface leaving only the coral reef to emerge, thanks to the corals activity. This particularity makes these organisms the biggest known building constructors of the living world. Atolls represent the last stage of our islands evolution, making them the oldest islands of all.
Lagoons truly are oasis of life in the deep-sea desert. Shelter for the prey, hideout for the hunter, nursery, food source, nesting area, coral meets many uses for the diverse and abundant life that relies on it. But it is also a very fragile environment. Hurricanes, coral eating starfish (Acanthaster planci) infestation, embankments, urbanisation, pollution and also direct destruction of the coral are the many threats capable of weakening or progressively destroy our coral reefs.
Creation of Underwater trails
Along the trail: visiting the underwater world…
An underwater trail is a subaquatic itinerary, accessible to all, to discover what is hidden under the surface of the lagoon. The visitor is usually equipped with fins, mask and snorkel. Along the itinerary, the visitors follow buoys and can read information on special submerged boards.
Convinced that underwater trails serve its conservation and education mission, te mana o te moana decided to develop this activity in French Polynesia.
Te mana has developed a know-how concerning every step of the creation of a new underwater trail: checking the richness of the area, defining the itinerary, installing the beacons, creating the educational tools and information leaflets, etc…
In French Polynesia, the first underwater trail was created within the hotel InterContinental Moorea Resort & Spa, in an artificial lagoon that was digged at the time the hotel was constructed. The lagoon’s fauna and flora being rather poor, the first step was to enrich the marine life in the lagoon (see below: creation of Moorea’s Coral Garden at the InterContinental Resort and Spa), prior to creating the ReefQuest underwater trail.
The Underwater trail is accessible for free for visitors equipped with their own mask. Two posters (corals and fishes) are displayed at the Fare (lagoon’s entrance), and information booklets (fishes, algae, invertebrates) are available.
In March 2009, students involved in the sea class of the Moorea sailing school were the first to discover the Mareto underwater trail.
This underwater trail located in the Opunohu bay in Moorea offers to students an unforgettable visit of the underwater world. It will be a new activity for children who practice sailing in the Moorea sailing school.
Developed and installed by te mana o te moana, it is composed of 5 stations with submerged information boards on coral reef ecosystem. Te mana o te moana has been previously involved in raising children’s awareness on marine environment protection within the SAGA project.
The trail complies with local legislation of lagoon protection and management (PGEM). The information boards are removed after each visit.
Maupiti’s underwater trail was created by te mana o te moana in August 2008. Initially, it was Ronald Le Piniec who wished to open a diving Club on Maupiti (Leeward Islands), and also wanted to diversify the activities proposed to the clients.
He therefore asked te mana o te moana to create an underwater trail. This included:
– studying the area to determine the best potential location
– description of the fauna and flora present in the area
– definition of the itinerary
– creation of submersible factsheets and other documents for the visitors
– training of accompanying guides
The underwater trail includes five stops, offering to the visitor great opportunities to discover marine fauna and flora, and to raise awareness on marine conservation.
Download the 4 submersible fact-sheets (in French): fiches immergables du sentier sous-marin de Maupiti
Download the Study for the creation of an underwater trail on the island of Maupiti (final report, in French): Rapport étude sentier sous-marin Maupiti
Creating Coral Gardens consists in enriching artifically poor or degraded areas in order to create a new coral reef and to attract various species of fauna and flora that will naturally colonise the area.
This operation requires special techniques, such as coral restauration, transplantation and fixation of cuttings. It is usually monitored by a scientific survey.
Moorea’s Coral Garden at the InterContinental Resort and Spa
This is the Coral Garden where the ReefQuest Underwater Trail was created (see above: creation of the ReefQuest Underwater trail on Moorea island). This work was started in 2004 and done by the CRIOBE (a local research institute).
First of all, basalt blocks were immerged in the lagoon, then corals were transplanted and fixed on these rocks. Scientific monitoring checked the good health of the corals, and soon revealed that various fish species settled naturally in this brand new coral reef area. Good news!
In 2007, te mana o te moana introduced new corals and fishes to increase diversity along the underwater trail. In 2010, new developments have been added to improve the area.
Some 80 species of fish and many algae and invertebrates now live in the corals, rocks and sandy areas of the underwater trail.
InterContinental Resort and Thalasso Spa Bora Bora started a collaboration in February 2009 with te mana o te moana, aiming at creating a coral garden and a ray feeding area in the hotel channel.
The first stage of the project comprising coral transplantation and creation of a coral garden was completed in April 2009.
More than 700 coral colonies were transplanted. Regular scientific monitoring has been conducted in order to study and observe transplanted corals.
The objectives of the coral garden are to create a living habitat for various marine species and to raise awareness on marine environment. Educational supports and guides are available for visitors for a better understanding of the underwater world.
Download the Final Report (in French): Rapport final d’activités – Création d’un Jardin de Corail – InterContinental Bora-Bora
Download the Underwater mini-guide to Coral Garden – Bora-Bora
As part of the environmental concern expressed by the hotel InterContinental Tahiti, te mana o te moana has been requested to initiate and coordinate an activity aiming at restoring the “Fare I’a” reserve. Also called “the lagoonarium”, this artificial area includes an underwater landscape layout with coral garden and marine animals.
After confirmation by the technicians of the hotel of the good quality of the water and perfect functionning of the new water pumps, Te mana o te moana planned the layout during the months of July and August 2011, the best period to ensure survival of transplanted coral reefs.
Te mana o te moana worked in partnership with BoraEcoFish company, which is specialized in post-larva fish breeding and collecting and on reef layout. Additionally, 104 giant clams (Tridacna maxima) from the aquaculture company Tahiti Marine Aquaculture, were reintroduced on two sites.
This project reintroduced 800 coral reef colonies and aroud 100 clams. Monthly monitoring is done by BoraEcoFish. Thanks to the variety of coral colonies reintroduced, and of the new marine landscape created, life is back in the Lagoonarium, which has become a rich and secure place to discover coral reefs.
Download the Final Report (in French): Création d’un jardin de corail au sein du Lagoonarium de l’hotel InterContinental Tahiti – Rapport final d’activités
This post is also available in: French