Editorial Toward sustainable pearl-oyster culture, in a changing environment: Recent findings and issues from the POLYPERL project (2012e2015) The pearl industry, using the black-lip oyster, Pinctada margari-tifera, is a central economic issue for French Polynesia. Initially developed in the early 1990s, after a brief'golden age', the pearl industry faced a decade of decline. As described in Gueguen et al., several research programs were therefore conducted to better analyze the functioning of this industry and to attempt to identi-fyissuesrelated to the improving the quality of the pearls as well as the functioning of lagoons. To complete this knowledge, during a 4 year period, the POLYPERL project, funded by the French National Research Agency (ANR), was a federative initiative that focused, simultaneously and for the first time, on socio-ecological and economic aspects of the pearl industry. The originality of the POLYPERL project consists of successfully implementing an integrated and multidisciplinary research-action approach in close association with both pearl farmers and the Polynesian authority in charge of management of the pearl industry (Direction des Ressour-ces Marines et Mini eres de Polyn esie, DRMM). In the context of the global change, the vulnerability of the pearl industry represents a major concern. As emphasized by Le Moullac et al. a), the warming of the water will have a significant impact on the physiology of mother of pearl, inducing a metabolic deficit. The energy metabolism, ingestion, oxygen consumption and, hence, the scope for growth (SFG) were maximum at 30 C and dropped dramatically at 34 C. On the other hand, the influence of acidifica-tion (increase of pCO2) showed that the shell growth rate of the pearl oyster could be slowed without threatening the species, since the management of energy and reproduction functions appeared to be preserved (Le Moullac et al., b). These authors also found that the thermal optimum for biomineralization and for energy management was different. So with regard to the Intergovernmental Panel on Climate Change (IPCC) projections, pearl oyster stocks (wild and reared) could be severely threatened in the next decade due to water warming. This point is of particular importance, as environmental conditions prevailing in the water column can control the pearl industry in different ways. First of all, because pearl oyster production in French Polynesia only relies on natural spat collection, knowledge of the renewal of the pearl oyster resource in atoll lagoons is a key step towards the sustainable management of the industry. The variability of lagoon-scale connectivity patterns and recruitment potential was investigated by coupling a validated 3D larval dispersal model, a bioener-getics larval growth model following the Dynamic Energy Budget (DEB) theory and a population dynamics model (Thomas et al.). This approach results in a better understanding of how the spatial heterogeneity of trophic resources modulates larval growth, acting on the intra-lagoon connectivity. Analysis of the distribution and population structure of the wild stock of pearl oysters (Andrefouet et al.) revealed their potential contribution as a source of reproductive material released in the water column. On the basis of these findings, new management proposals were suggested, regarding the interest of establishing sanctuaries and installing mature females in suitable locations, which can be identified from connectiv-ity matrices. Secondly, the environment can have a direct effect on the size of pearls. Pearls are cultured using a pearl oyster (so called " mother of pearl ") by adding both a nucleus and a graft which is a piece of the mantle of another oyster (called the " donor " oyster) inside the mother of pearl. In their study, Blay et al. explore genetic versus environmental impacts on the size of pearls as well as the genetic  environment interactions. Their experimental grafting approach in two contrasting macrogeographical lagoons, highlighted a genetic effect for nacre weight and thickness for the two studied sites. A similar study, conducted at a larger scale (5 lagoons), clearly confirms the influence of temperature and trophic conditions (Le Pabic et al.). Moreover, recipient oysters regulate the gene expression in the pearl sac (originating from the mantle of the donor oyster used for the graft) at family and/or individual levels. The functioning of the pearl sac is controlled by the recipient oyster (e.g. mother of pearl) that provides energy, the supply of which is dependent on environmental conditions. The phenotypic expressions of the two biomineralizing tissues in the recipient oyster were consistent (mantle and pearl sac). Thirdly, interaction with the environment also means that cultivated oysters can directly impact the functioning of the lagoon ecosystem. Here, we point out that pearl oyster culture can stimulate nutrient cycling in the water column (Lacoste & Gaertner-Mazouni). The biological activity of reared communities (i.e. pearl oysters and epibionts) is directly responsible for inorganic N and P regeneration and contributes to the requirement of phyto-plankton for primary production. In such oligotrophic systems, nutrient regeneration due to aquaculture is higher in the water column than at the sediment interface, since depth probably limits the benthic-pelagic coupling. Innovative practices in pearl farming were also explored as they could constitute a way to improve sustainability, through improvement of the cost-effectiveness of the pearl industry. Investigated in Latchere et al., the potential effect of electrolysis on the biominer-alization capacities and growth rate of juveniles of Pinctada Contents lists available at ScienceDirect