Surveying the marine environment around Denis Island

From the 19th-24th May GIF staff carried out marine surveys around Denis Island. The new Denis Island conservation team was given the opportunity to assist and learn the methodologies used by GIF staff. There are three key areas of importance surrounding  Denis Island consisting of the beaches and intertidal flats, the adjoining reef / sea grass flats to the north, east and south of the island and the area stretching along the western edge of the Denis Island plateau.

With these marine surveys (which involve coral, fish, seagrass bed, invertebrates and megafauna monitoring) GIF is establishing a baseline that allows for adaptive management of the marine areas around the island in view of the upcoming proclamation of the waters around the island as legally protected area.

Coral surveys were carried out to determine the percentage cover of benthic communities and diversity using Line Intercept Transects (LIT). Invertebrates living on the reef were also identified along the transect lines, whereas fish species were identified through fish point counts at several stationary points. 

The seagrass beds were surveyed through snorkelling and kayaking and all sightings of megafauna such as turtles, sharks and rays were recorded as well as schools of juvenile reef and mobile fish.  Baited Remote Underwater Video Systems (BRUVS) were deployed to investigate the presence of large predators and megafauna densities around the island.

Marine surveys are usually carried out once or twice a year to identify the presence and distribution of key species and monitor changes in the coastal marine habitats. Gathering data of Denis' relatively pristine marine ecosystems will not only help to better understand fish and coral communities but also to support the proclamation of a marine protected area around the island.This exercise was co-funded by the GEF-UNDP-GoS project ‘Strengthening Seychelles’ protected area system through NGO management modalities’.