ИСТИНА

Coral reefs shallow waters of La Réunion (South-West Indian Ocean) were investigated for medusae for the first time. The study was done during a whole year, from November 2005 to October 2006, on eight stations of the west coast. Each station was sampled twice a month by vertical samplings at 10 and 50 meters depth with a plancton net of 55 microns mesh. To increase chances to catch medusae for inventory, additional samples were done (i) by doing horizontal trawls (ii) by visual catching near the surface. Fortyeight medusae species were recorded. The most diverse and abundant are Hydrozoa medusae (44 species), Scyphozoa are presented by two species (Thysanostoma thysanura Haeckel, 1880 and Atolla wyvillei Haeckel, 1880). Two findings of Cubozoa (Caribdea sp.) and the first record from La Réunion of Stauromedusae were registered. Among Hydrozoa, 50% of the species belong to Anthomedusae, 25% to Leptomedusae and 25% to holoplanktonic Automedusae. As in other parts of the world ocean, the last one dominates in all samples (Aglaura hemistoma (Péron & Lesueur, 1809), Solmundella bitentaculata (Quoy & Gaimard, 1833) and Liriope tetraphylla (Chamisso & Eysenhardt, 1821)). The first record of Zanclella diabolica Boero, Bouillon & Gravili, 2000 and Cnidocodon leopoldi Bouillon, 1978 for La Réunion was made. Reverse developing of Turritopsis nutricula and Laodicea sp. medusae was observed.