Abstract

Coral mortality has been increasing over the last 30 years in the Caribbean, making coral recruitment critical for sustaining coral reef ecosystems and contributing to their resilience. Dynamics of coral communities is partly controlled by larval recruit-ment. However, the accurate identification of coral recruits remains difficult (size < 2 mm). Genetic markers permit to distinguish coral species commonly observed in Caribbean studies. The objective of the study was to examine the temporal variability in the recruitment of corals larvae from 2010 to 2012 in Guadeloupe Island. For that, twenty terracotta settlement plates were fixed on a grid and immersed every month at 5 m, 10 m and 20 m depth. COI and ITS region as a genetic marker were used for the identifica-tion of coral recruits. Larvae settlement was observed all year round and presented an important peak between March and June. Temporal variability in the density of coral recruits occurred at all depths. Among the 276 recruits collected, genetic identification revealed seven different species. The highest settlement was shown by Agaricia sp. and Porites astreoides at all depths followed by Favia fragum, Madracis sp., and other Porites sp. Settlement appeared to be inversely related to depth. The taxonomic composition of the recruits reflects the structure of juvenile but not adult coral communities. To conclude, the initial phase of the life cycle plays an important role in the establishment and survival of Scleractinian corals. The understanding of the mechanisms of post-settlement mortality of recruits could improve the knowledge necessary to maintain coral populations.

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