Conservation of marine sponges in the Mascarene archipelago

Sponges are ecosystems engineers that play important roles in marine ecosystems. Currently about 8, 000 species are recognised, but it is thought that because of their lack of obvious morphological characteristics, their... [ view full abstract ]

Sponges are ecosystems engineers that play important roles in marine ecosystems. Currently about 8, 000 species are recognised, but it is thought that because of their lack of obvious morphological characteristics, their global biodiversity is vastly underestimated with knock-on effects for including sponge biodiversity in conservation efforts. The situation regarding a lack of knowledge of sponge biodiversity is no different in the Indian Ocean than it is globally, with no studies on sponge biodiversity in the Mascarene region. Consequently, the three islands (Mauritius, Rodrigues and Reunion islands) forming the Mascarene archipelago were surveyed for sponges at depths ranging from 0 to 30m. A total 413 specimens were sampled and identified morphologically using spicule and skeletal analyses. Molecular analyses were carried out using CO1 and 28S markers at the Stellenbosch University. Preliminary results show three islands of different sponge faunas with numerous previously undescribed species observed. With information on sponge biodiversity coupled with phylogenetic and phylogeographical analyses, this study will provide the first baseline information on sponge biodiversity in the Mascarene region. The overall aim is to use data and information generated in this study to strengthen integrated conservation planning for marine sponges and to use the findings as an example for integrating genetic information into conservation planning.