Informing conservation planning in a tropical insular system using decision support tools: application to the management of giant clam resources in French Polynesia

Giant clams are an endangered natural resource of important nutritional and economic value for remote islanders of French Polynesia. Despite the highest densities of the species Tridacna maxima worldwide having been recorded in Tuamotu Archipelago atolls, exploitation and international exports from these atolls remain dependent on stock management measures. In particular, rare but consequential mass mortality events have affected clam populations in several atolls in the recent past. This calls for new conservation actions designed to limit risks for individual atolls and based on decisions considering a network of atolls. Systematic conservation planning (SCP) offers an efficient approach to explicitly prioritize the protection of areas in such a multi-atoll space. In this study, we integrated stock, density and population structure data with socio-economic data on fishers’ habits to find compromises between meeting targets of stock representation within marine protected areas (MPAs) while minimizing the cost of conservation to fishers. In addition, zones less likely vulnerable to mass mortality were included in marine protected areas in priority. Eventually, a potentially adequate network of MPAs was selected among a portfolio of possible solutions constrained by different conservation objectives and cost functions. The selected MPA network reached several targets of stock representation (e.g. 30% of the overall stock and high density areas), while maximising equity among atolls in terms of their contribution to protection and incurred costs. The value of this approach is discussed, as well as the interest of further research. For this project, we used geographic information systems and the SCP software Marxan.

Promotor(s) & Supervisor: Serge Andréfouët, Roger Laroque, Anse Vata, Baru Perancak
Thesis Institute: Institut de Recherche pour le Développement (IRD)

ISCED Categories

The highlighted icons, represent the fields of education (in compliance with ISCED Classification) engaged during this course/programme.

0511 - Biology", "0521 - Ecology", "0522 - Conservation and environmental management", "0312 - Policy and governance