Van Wynsberge S. auteur aut IRD Andréfouët Serge auteur aut IRD Gaertner-Mazouni N. auteur aut IRD Wabnitz C. C. C. auteur aut IRD Menoud M. auteur aut IRD Le Moullac G. auteur aut IRD Levy P. auteur aut IRD Gilbert A. auteur aut IRD Remoissenet G. auteur aut IRD text journalArticle eng text/pdf reformatted digital access 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. specialized POLYNESIE FRANCAISE 040 036 12 1 e0170565 [20 p.] 2017 1932-6203 https://www.documentation.ird.fr/hor/fdi:010069309 10.1371/journal.pone.0170565 1932-6203 [F B010069309] https://www.documentation.ird.fr/hor/fdi:010069309 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/divers17-03/010069309.pdf IRD - Base Horizon / Pleins textes 2017-04-04 2023-07-11 fdi:010069309 fre