Reef benthos of Seychelles - A field guide

Abstract

During the 2019 First Descent Seychelles Expedition, a variety of underwater technologies were deployed to survey the benthic flora and fauna of Seychelles Outer Islands’ shallow to deeper reefs. Submersibles, remotely operated vehicles (ROVs), and SCUBA diving teams used stereo-video camera systems to record benthic communities during transect surveys conducted at 10 m, 30 m, 60 m, 120 m, 250 m and 350 m depths. In total, ~45hrs of video footage was collected during benthic transect surveys, which was subsequently processed using annotation software in order to assess reef biodiversity and community composition. Here, we present a photographic guide for the visual identification of the marine plants, corals and other common invertebrates that inhabit Seychelles’ reefs. It is hoped that the resulting guide will aid marine biologists, conservationists, managers, divers, and naturalists with the identification of organisms as seen in underwater footage or live in the field.A total of 188 morphospecies were identified belonging to Octocorallia (47), Porifera (35), Scleractinia (32), Asteroidea (19), Echinoidea (10), Actiniaria (9), Chlorophyta (8), Antipatharia (6), Hydrozoa (6), Holothuroidea (5), Mollusca (2), Rhodophyta (2), Tracheophyta (2), Annelida (1), Crinoidea (1), Ctenophora (1), Ochrophyta (1), and Zoantharia (1). This represents the first attempt to catalogue the benthic diversity of reefs to 350 m depth in Seychelles.

Keywords

• coral reefs
• mesophotic coral ecosystems
• benthos