Takara Tabu Marine Reserve, Vanuatu — Trochus Density Rises Locally, Reserve-Wide Gains Not Yet Significant After Three Years

In North Efate, Vanuatu, the village of Takara established a 0.2 km2 customary marine reserve (tabu) over fringing reef in 2008 under the Vanuatu Fisheries Department's community-based fisheries management programme, closing the area to harvest of trochus (Tectus niloticus), a heavily targeted shell fishery used for both food and the mother-of-pearl button trade.

In December 2011 - three years into closure - Dumas et al. (Vanuatu Fisheries Department / Institut de Recherche pour le Developpement) surveyed trochus density, biomass and shell size inside and outside the reserve, splitting the reserve into northern and southern zones to test whether trochus, a mobile species that actively searches out suitable habitat, concentrated unevenly.

Harvestable trochus density was ten-fold higher in the reserve's southern zone than its northern zone (110 vs 8.33 individuals/ha), with total biomass thirteen-fold higher there. Shells were on average about 19% larger inside the reserve overall (mean diameter 113.5mm vs 95.2mm outside). But comparing the full reserve against paired outside sites, the density difference (90.6 vs 62.0 indiv/ha) was not statistically significant after three years - evidence that a mobile species' own habitat-seeking behaviour, not protection alone, can drive locally uneven benefits.

A companion study on neighbouring Emau island (Dumas et al., Environmental Conservation, 2010) found trochus abundance responded strongly only within an older, larger tabu area after four years of closure, while a co-managed green snail (Turbo marmoratus) population had already collapsed beyond recovery despite protection. Together the studies, carried out under Vanuatu's national EFITAV project on tabu-area effectiveness, show that customary reserves can produce real, measurable gains for shellfish, but that results depend on reserve age, size and species mobility, and take years of sustained village enforcement to become statistically robust.

Read the full analysis: https://www.academia.edu/50551637/Efficiency_of_tabu_areas_in_Vanuatu_EFITAV_project_PROJECT_REPORT

Read the full analysis: https://www.academia.edu/50551637/Efficiency_of_tabu_areas_in_Vanuatu_EFITAV_project_PROJECT_REPORT