Abstract

Mauritius is strategically located in the Indian Ocean and its marine environment plays a vital role in the national economy. Over the past few years Mauritius has seen rapid development and the tourism sector has been one of the main pillars for the flourishing economy. Tourism has brought a lot of foreign direct investment leading to the construction of several high class hotels and these have provided for numerous direct and indirect employments within the sector. These hotels have several requirements in view of ensuring quality and luxury of the establishment and amongst those would be nice sandy beaches adjacent to an appropriate lagoon. Considering the size of the island and the little space available along the shore, the hotels are now being constructed in areas with previously no sandy beaches and thus provisions had to be made for beach improvement work and lagoon rehabilitation. These works have to include methods for the implementation of sustainable beaches as sand remains costly. Various methods have been applied locally and the most promising being the Permeable Submerged Breakwater (PSB) whereby heavy basaltic rocks are laid within the lagoon to minimize the effect of waves and current reaching the shore. In addition, these PSB is found most appropriate as substrate for coral recruitment and coral transplant. This research investigated the colonization of various species in 3 Stations and the PSB in the north-west region. These structures have created habitats not only for corals but fishes and other organisms whether natural reefs structures were present or absent. Biodiversity around the PSB have increased rapidly with different coral species. Coral recruitment (<2mm) were 2.0 ± 1 recruits/m2 (mean ± SD) on Station 1 (Control), 3.0 ± 1 recruits/m2 (mean ± SD) Station 2 and 3 ± 1 recruits/m2 (mean ± SD) for Station 3. The number of coral recruits over the PSBs, 3.0 ± 1 recruits/m2 (mean ± SD) and 40% survival rates over a 10-months period clearly shows that corals are adapting to the environment but a lack of proper substratum may be the cause for reduced recruitments in certain reefs. These results are indicative that there is a need for active management of the current environment and habitat degradations has been the main source for coral depletion and biodiversity lost.