ANIMAL COMMUNITIES AND HYDROTHERMAL ACTIV ITY ON THE EAST PACIFIC RISE BETWEEN 17-DEGREES-S AND 19-DEGREES-S (NAUDUR CRUISE, DECEMBER 1993)

70 hydrothermal sites were observed during the 23 dives of the French submersible Nautile (''Naudur'' cruise, December 1993), at 17-degrees- 19-degrees-S on the East Pacific Rise. Large vent-animal communities a re present around these sites. The zoological composition of these com munities is the same as that of the communities at 11-degrees-13-degre es-N and 21-degrees-N on the East Pacific Rise. However, the distribut ion of the species on the sites is different from all the other hydrot hermal communities; large anemone fields of several hundred square met res, associated with colonies of Bathymodiolus and Calyptogena, have b een observed. Fresh lava areas seem to bear the most important biologi cal activity.