Environmental impact assessment : coral frame project at Makunufushi, Kaafu Atoll

Abstract

The potential environmental impacts of the development of a coral propagation project on the island of Makunufushi operated by Cocoa Island Resort are assessed. The assessment exposes the solutions and preferred alternatives as well as mitigation measures to minimize any negative impacts whilst trying to derive the maximum positive impacts from the project. 2. It is important to be proactive in reef restoration. Therefore, the resort management wishes to enhance the aesthetic and recreational value of the property by propagating corals using a technique already demonstrated in the Maldives, the coral frames. 3. The coral frames will be deployed in the vilu, near the two northern jetties between 1 and 10 m depth and along the south-western jetty at about 2 m depth. Coral fragments will be attached by a marine biologist and these small fragments will develop into full colonies within a few years. Coral fragments from the house reef will provide a small number of fragments and the mother colonies will heal rapidly. Preference will be given to damaged colonies. 2000 frames of 1 m2 will be initially deployed, and after the first batch, the existing frames will provide fragments for transplantation in the future. The project will start as soon as approval is granted, and as this is a long term project, it could span several years before completion. 4. Makunufushi is a 620 m long island located on the south western part of the reef. The northern side of the reef is protected inside the lagoon, whereas the southern side is located in Kandooma Kandu, a major channel into the South Male’ Atoll. 5. In Kandooma Kandu, the strong current is incoming or outgoing depending on the tides. The diffracted waves from the oceanic swell reach the southern coast of the island and also the northern coast from a north-east direction. The wind waves lead to an extension of the eastern tip during the south-west monsoon and of the western tip during the north-east monsoon. 6. Photographic transects were used to assess the benthic cover of 10 sites, where 10 pictures in each transect is analyzed using 25 point randomly chosen to obtain quantitative substrate cover data of morphological characteristics of the reef community. The dominant substrate was rock (52.72±12.62%) followed by live coral (21.6±6.61%) and rubble (17.04±8.99%). The coral cover was significantly higher on the north side than on the southern part of the reef flat (27.0±7.30% vs 5.80±1.93%) and on the slope at 20 m (24.8±8.81% vs 2.4±5.54%). Furthermore, Acropora sp. seemed to dominate the northern reef (between 45 and 95% of relative coral cover) whereas Coral encrusting is the major coral category at south (between 48 and 64% of relative coral cover). 7. For the fish community survey, data was collected using the methodology outlined by FishWatch Maldives, where 3 x 15 minute fish counts were made at each site. Surveys were carried out at 4 sites. Thirty nine of the 76 FishWatch target species were recorded among 15 families. The species on the target list with the greatest density were as follows: Lutjanus gibbus (33.17%), Zanclus cornutus (8.35%) and Chaetodon collare (6.14%). On the northern side, Chaetodontidae (25%) and Serranidae (23%) were the most abundant families, whereas it was Lutjanidae (56%) and Chaetodontidae (15%) on the southern reef. 8. Disturbance to the sea bed will be minimal as coral frames will mostly be installed on a rocky substrate and will be elevated 6 feet. Coral frames are made of 12mm thin iron bars, which creates very little drag for water flow. 9. It has been noticed that coral frames attract and recruit a lot of fish life and increases the complexity of the reef. It is anticipated that this will also be the case in Makunufushi, the area eventually developing into a more productive reef. This work will directly improve the aesthetics and the reef complexity of the area, which will also improve the recreational value of the resort. 10. To avoid the loss of biodiversity among corals, a wide array of species will be tried out. The project will focus on Acropora sp. as it represents the most dominant coral family in the Maldives, but other families will also be transplanted such as Pocillopora sp., Psammocora sp. and Echinopora sp.. 11. If frames are not transplanted or pruned properly or the location is unsuitable, corals may die, though in majority of the previous projects, this has not been encountered, and the result has been found to be very positive. As possible death of fragments and donor colonies are the only problem that need to be mitigated, if necessary, they will both be monitored as part of the study. When choosing donors, priority will be given to those corals that have already been damaged by natural or anthropological activities, and eventually the corals grown on the frames will be used to provide fragments. 12. The do nothing scenario will probably lead to more decrease in coral cover, and the aesthetics of the reef will not improve. The resort may also lose some of its public relations benefits as they will not be seen as being proactive in its environmental restoration.