The University of Reunion Island organized in October 2016 one-week expedition in Rodrigues Island for exploring and sampling marine sessile organisms.
At the heart of the Indian Ocean, at latitude 19°43’ S and longitude 63°25’ E, Rodrigues Island stretches over a surface area of 108 km2 measuring only 18 km in length and 8 km at its widest point. It is the smallest of the Mascarene Islands and a dependency of Mauritius. Rodrigues is entirely surrounded by coral reefs offering a great marine biodiversity. The lagoon and coral reefs of Rodrigues are twice the area of the islands.
Rodrigues is a well-preserved island where people live simply. The particular charm of the island comes mainly from the calm and harmonious lifestyle of its inhabitants. English is the official language of the island, though French is widely spoken. Créole (a mixture of French and various African dialects), Indian and some oriental languages are also spoken.
Guided by a local diving club, a team of 5 divers (3 Professional divers and 2 Scientifics) has explored the lagoon for sampling sponges and their associated microorganisms. The objectives of such a sampling is first to have a better knowledge of the marine biodiversity and then to find bioactive marine natural products for important economic areas such as cosmetics and health, using relevant biological and chemical methods.
Prospection and sampling were conducted by scuba diving all around the coasts The sampling was performed following precise and standardized experimental protocols:
At the collection site, all available biotic and abiotic information such as coordinates of sampling site (with GPS), depth and date were recorded. Underwater, in situ photography were taken in order to give essential information concerning color and shape of the specimen.
The sessile animals (only those in abundant quantities underwater) were carefully levered off with a thin-bladed knife to prevent damage. For chemical investigation, each specimen (200 to 500g wet weight) was separately put in a bag with a specific number. For microbiological investigation, the same samples were put in a sterile tubes. Out of the water, each specimen was immediately frozen and kept at minus 20°C.
67 samples of sponges belonging to 20 different genera were collected and identified on a taxonomic point of view. The chemical and microbiological studies on these samples are ongoing.