Overexploited for the Asian market, white sea cucumbers(Holothuria fuscogilva) are now recognized as vulnerable (IUCN Red List) and listed in CITES (Appendix II). To participate in the conservation of this species, it is essential to understand the animal’s behavior in the wild, its distribution and its stock. The study is taking place in Vairao (southwest coast of Tahiti), where the holothurian hatchery is based. Underwater assessments have identified 10 sites suitable for the aggregation of the species. These sites represent 15% of the lagoon’s total surface area and are categorized into 3 types of geomorphological zones: pass approaches, deep channels and the lagoon’s inner slope. The results show a density of 53 ind./Ha in the pass approaches, 41 ind./Ha in the channels and 125 ind./Ha on the inner slopes, i.e. an average density of between 65 ind./Ha (low estimate) and 73 ind./Ha (high estimate).