Five main marine communities
• The algae are separated into three groups: the macroalgae, the filamentous algae that constitute a seagrass and the coralline encrusting algae.
• The hard corals encompasses the order of the Cnidarians that build a hard skeleton which consists of the Hydrocorals (class of Hydrozoans) et the Madreporaria (class of Anthozoarians).
The other orders of hard corals such ass the Sylasteridae (class of Hydrozoans) our the Anthipatharia (class of Anthozoarians), for instance, do not occur in the working zone (neither in the lagoon nor on the outer slope).
The Helioporidae and the Stoloniferia (class of Anthozoarians) do not occur in French Polynesia.
• For the molluscs and echinoderms, all the species that are above ground of size bigger than five centimeters are taken into account. The species that live under ground are not sampled.
Examples of counted species: Diadema, Echinometra mathaei, White Echinothrix, Notched Echinothrix, Black Echinothrix, Bohadschia argus, Microthele nobilis, Arca ventricosa, Chama imbricata, Spondilus sp, Tridacna maxima, Anemone, Commercial top shell, Cots.
• The fish are separated in three age categories estimated "in situ" from their size: the juveniles of the year, the juveniles of the previous years and sexually matures adults. The fish are assembled in two sets : the juveniles of the year and the rest of the population is named adults by convention.
Amon the five studied communities, three of them are down to the species level: the molluscs, echinoderms and fish. The algae and hard corals are studied down to the genus level.
|Studied communities||Taxonomic level||Quantitative descriptor||Unit|
|Algal turf (1)||-||Cover||Percentage|
|Coralline encrusting algae (2)||-||Cover||Percentage|
|Molluscs||Species||Species richness and density||Number of species and individuals per 100 m²|
|Echinoderms||Species||Species richness and density||Number of species and individuals per 100 m²|
|Fish||Species||Species richness and density||Number of species and individuals per 100 m²|
(1)The sea grass are mostly Rhodophyceans
(2)The coralline encrusting algae (Rhodophyceans) are mostly of the genuses Lithothamnion and Porolithon
Quantitative descriptors (for the barrier reef and the outer slope)
>the percentage of coverage
>the species richness (number of species for 100 m²)
>the density (number of individuals for 100 m²)
Category of the trophic diet for adult fish (for interannual variations)
4- Diurnal carnivorous
5- Nocturnal carnivorous
|Rubble (R)||All free hard coral fragment between 0.2 and 15 cm.|
|Sand (S)||Sendiment which fragments of size less than 0.2cm and do not stay in suspension when stirred.|
|Live coral (C)||All living hard coral|
|Turf (T)||All thin turf|
|Coralline encrusting algae (P)||All the coralline encrusting algae|
|Macroalgae (A)||All non coralline algae easily indentified.|
|Other (O)||Any other organism (anemone, shell, waste, soft coral,...).|
|Pavement (D for dalle in French)||All the hard an compact surfaces without encrusting algae nor turf nor macro algae. NB. this category remains scarce.|