Shell growth, reproduction, and natural mortality of the giant clam Tridacna maxima were characterized over a two-year-period in the lagoon of the high island of Tubuai (Austral Archipelago) and in the semi-closed lagoon of Tatakoto (Tuamotu Archipelago) in French Polynesia. We also recorded temperature, water level, tidal slope, tidal range, and mean wave height in both lagoons. Lower lagoon aperture and exposure to oceanic swells at Tatakoto than at Tubuai was responsible for lower lagoon water renewal, as well as higher variability in temperature and water level at Tatakoto across the studied period. These different environmental conditions had an impact on giant clams. Firstly, spawning events in the lagoon of Tatakoto, detected by gonad maturity indices in June and July 2014, were timed with high oceanic water inflow and a decrease in lagoon water temperature. Secondly, temperature explained differences in shell growth rates between seasons and lagoons, generating different growth curves for the two sites. Thirdly, local mortality rates were also found to likely be related to water renewal patterns. In conclusion, our study suggests that reef aperture and lagoon water renewal rates play an integral role in giant clam life history, with significant differences in rates of shell growth, mortality and fertility found between open versus semi-closed atoll lagoons in coral reef ecosystems.
Université de la Polynésie Française, UMR 241 EIO, Laboratoire d’Excellence CORAIL, Faa’a, Tahiti, French Polynesia;Institut de Recherche pour le Développement, UMR 9220 ENTROPIE (Institut de Recherche Pour le Développement, Université de la Réunion, Centre National de la Recherche Scientifique), Laboratoire d’Excellence CORAIL, Nouméa, Nouvelle-Calédonie;Institut de Recherche pour le Développement, UMR 9220 ENTROPIE (Institut de Recherche Pour le Développement, Université de la Réunion, Centre National de la Recherche Scientifique), Laboratoire d’Excellence CORAIL, Nouméa, Nouvelle-Calédonie;Université de la Polynésie Française, UMR 241 EIO, Laboratoire d’Excellence CORAIL, Faa’a, Tahiti, French Polynesia;The Pacific Community (SPC), Noumea, New Caledonia;Université de la Polynésie Française, UMR 241 EIO, Laboratoire d’Excellence CORAIL, Faa’a, Tahiti, French Polynesia;Ifremer, UMR 241 EIO, Laboratoire d’Excellence CORAIL, Taravao, Tahiti, French Polynesia;Ifremer, UMR 241 EIO, Laboratoire d’Excellence CORAIL, Taravao, Tahiti, French Polynesia;Ifremer, UMR 241 EIO, Laboratoire d’Excellence CORAIL, Taravao, Tahiti, French Polynesia;Ginger Soproner, Noumea, New Caledonia;Direction des Ressources Marines et Minières, Fare Ute, Papeete, Tahiti, French Polynesia
Recommended Citation:
Simon Van Wynsberge,Serge Andréfouët,Nabila Gaertner-Mazouni,et al. Growth, Survival and Reproduction of the Giant Clam Tridacna maxima (Röding 1798, Bivalvia) in Two Contrasting Lagoons in French Polynesia[J]. PLOS ONE,2017-01-01,12(1)