Sparks, Conrad A.J.Gibbons, Mark J.2015-11-172015-11-172003Sparks, C. and Gibbons, M.J. (2003). Hydromedusae off the Orange River mouth, Southern Africa. African Journal of Marine Science, 25(1): 373-37602577615http://hdl.handle.net/10566/317A total of 242 zooplankton samples from the upper 100 m of the water column was collected discontinuously from March 1997 to January 1999 off the Orange River mouth on the west coast of southern Africa. Six species of hydromedusae were recovered at generally low abundance, of which Euphysa aurata, Leuckartia octona and Proboscidactyla menoni were dominant. E. aurata and L. octona showed evidence of seasonality in abundance. The low diversity of the fauna was remarkable and it is hypothesized that this might be attributable in part to sedimentation from the Orange River, and in part to locally weak circulation and the wide extent of the continental shelf.enThe South African Journal of Marine Science (now African Journal Marine Science) is published by NISC (Pty) Ltd and Taylor& Francis and available online at http://www.tandfonline.com/loi/tams20. Publisher authorised author to deposit this file.HydromedusaeJellyfishSeasonalityBenguela upwelling ecosystemDiversityArticle