Climate variability and massive mortalities challenge giant clam conservation and management efforts in French Polynesia atolls

Climate variability and massive mortalities challenge giant clam conservation and management efforts in French Polynesia atolls Andréfouët Serge auteur aut IRD Van Wynsberge S. auteur aut IRD Gaertner-Mazouni Nabila auteur aut IRD Menkès Christophe auteur aut IRD Gilbert A. auteur aut IRD Remoissenet G. auteur aut IRD text journalArticle eng text/pdf born digital access In 2004, the first no-take area (NTA) dedicated to the conservation of giant clams Tridacna maxima was implemented in Tatakoto Atoll, French Polynesia. This NTA protected a unique area worldwide, with extraordinarily high giant clam densities (up to 337 individuals per m(2) on 20-m transect). In 2012, a stock assessment survey revealed a dramatic decrease of the clam population. The reduced densities peaked at 38 ind m(-2) and the stock in the NTA decreased from 20.1 +/- 6.0 million to 1.9 +/- 0.55 million clams (mean +/- 95% confidence interval). Losses of similar proportions were observed throughout the atoll. Remarkably, the 83% overall loss of this natural resource used daily for consumption and for exports of clam meat to Tahiti Island went unnoticed by the local population. Field clues, including the size of live juveniles attached to the inside of dead shells, pointed to a massive mortality occurring about 3 years before the 2012 survey. Examinations of sea surface temperature satellite data identified a high range of temperature variations before March 2009. In agreement with past and recent events in other atolls, this anomaly is the most likely explanation of the massive loss of giant clams in Tatakoto Atoll, although the exact hydrological and biological secondary mechanisms that occurred in the lagoon remain unclear. The consequences of the massive die-off inside and outside the NTA require new long-term management strategies, by reinforcing the top-down national giant clam management arrangements and by setting flexible management objectives across a network of islands. specialized Tuamotu archipelago Tridacna maxima Fisheries management Community-based management CITES Top-down conservation Bottom-up conservation POLYNESIE FRANCAISE TUAMOTU GAMBIER 036 040 Biological Conservation 160 190-199 2013 0006-3207 https://www.documentation.ird.fr/hor/fdi:010060477 10.1016/j.biocon.2013.01.017 0006-3207 [F B010060477] https://www.documentation.ird.fr/hor/fdi:010060477 https://www.documentation.ird.fr/intranet/publi/2013/08/010060477.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2013-09-03 2017-08-23 fdi:010060477 fre