Abstract

This study, realized in July 2014 in the eastern region of Madagascar, particularly in Toamasina allows analyzing the state of vitality of marine ecosystems facing human activities and investment projects. Few cases were studied, among other mining activities, tourism, port infrastructure. The eastern region was chosen as the site of study because it brings the typical cases of what is happening in the Big Island in terms of potential impacts of investment projects on coastal and marine ecosystems. Several indicators were assessed, such as: the percentage of coral coverage of the substrate and the existing of bio-indicator species, the concentrations of heavy metals in water, sediments and biota, and the availability of fishery resources. The results obtained during this intervention showed thatthere are two major types of ecological underwater formations in the vicinity of Toamasina. These are coral reef and non-coral formations. This last one is represented either by sandy-muddy bottoms, or by rocky outcrops. From this study, it has been also noticed that several factors are among others responsible for the gradual degradation of the marine and coastal ecosystem in this area. The reef flat tends to have more degradation comparing to the reef slope. So far, the analysis of the heavy metal component extracted and analyzed using sediment and biotas, showed that there is not yet a significant threat to the biodiversity, but rigorous monitoring should be put in place to be able to follow on time any potential changes.

Keywords

coral reef, mining project, heavy metals, coastal and marine infrastructures, Toamasina, Madagascar