Abstract Summary
In response to the ongoing damage to coral reefs and the consequences on sand erosion, hotel industries in Mauritius have started to engage on beach and lagoonal rehabilitation works as well as coral farming as being a major part of conservation strategies. The project consisted of two parts. First, corals and marine organisms were removed along three (10m by 10m) area labelled Reef 1, Reef 2 and Reef 3 to accommodate Permeable Submerged Breakwaters (PSBs) made of basaltic rocks inside the lagoon. The marine organisms were displaced outside the working zones while corals were fragmented as well as whole corals colony removed. Hard corals were removed by fragmentation and loosening the whole colonies from their natural substratum. Line intercept transect (LIT) method was used to assess the percentage coral cover prior to removal process. They were placed on table nurseries and were carefully monitored for 1 month before transplantation. The second part involved the transplantation of corals on artificial structures placed next to the PSBs. One of the major aspects of this project has been to demonstrate the sustainable approach towards placement of artificial structures to prevent sand erosion while incorporating the ecological criteria. The present study investigated the culture of corals and success of coral farming before and after a beach and lagoonal rehabilitation work along with biodiversity regenerations over time after placement of these PSBs. Overall, number/unit of organisms removed were as follows: 1146 at Reef 1, 101 at Reef 2 and 970 at Reef 3 which comprised of molluscs, crustaceans and hard & soft corals. The overall percentage survivorship so far has been 95% with very few bleaching. Salinity, pH, DO, Temperature, Total Suspended Solids, nutrients (nitrates and phosphates) and Feacal Coliforms were monitored. In most of the experimental treatments the physico-chemical parameters were higher during construction activities and returned to normal range after construction as per the coastal water quality guidelines of Mauritius. These results are indicative that engineering solutions towards beach and lagoonal rehabilitation along with active restoration measures can be made possible.
