Effet des bungalows sur pilotis des hôtels en milieu corallien sur le peuplement ichtyologique

Increasing tourism in French Polynesia has encouraged resort development, especially on three islands of the Society Archipelago (Bora-Bora, Moorea, Tahiti). Although different resort stuctures have been developed, in 1993 there were 17 hotels consisting of bungalows built on piles along the fringing reef, and this kind of construction is becoming increasingly popular. Our study was designed to estimate the impact of such buildings on the local fish communities. Visual surveys were conducted by two observers at four resorts, under three bungalows built on piles and three adjacent control sites. Overall fish diversity and abundance was higher under the bungalows, with average increases of 10 % and 100 % respectively. A multifactorial ANOVA showed that observers produced consistent counts, so that the data could be reanalysed by a simpler two-factor model (bungalows, localities). Both terms were statistically significant and an interaction was detected. This occurred because one locality differs from the others. With the exclusion of this resort, which was the most modified site, the comparisons showed that bungalows have a strong positive influence on the local fish fauna. We attribute this result to the provision of food and shelter by these artificial structures which are generally located in otherwise simple habitats. While the benefit may be temporary for many species (i.e. providing suitable refuge space for juveniles but not adults), there was no evidence of any deleterious effect and recruitment to the local area may be enhanced through subsequent migration.