ZOOPLANKTON DISTRIBUTION IN THE COASTAL UPWELLING SYSTEM ALONG THE BANC-DARGUIN, MAURITANIA

In the framework of the Dutch Mauritania Expedition 1988, zooplankton was sampled in the beginning of the spring upwelling season at 44 stat ions along the Banc d'Arguin, Mauritania. Distribution patterns of oce anic and neritic copepod species and especially of the upwelling indic ator Calanoides carinatus (Kroyer) were analysed in search for direct proof of circulation of ocean upwelling water over the inshore banks. The vertical temperature distribution at the stations pointed to upwel ling in two different parts of the shelf area. According to the copepo d data the two upwellings were of a different nature. A restricted are a at the shelf edge near Cap Timiris appeared to represent a relativel y stable coastal upwelling situation. Upwelled water present near Cap Blanc was found to have traveled quite recently over a considerable pa rt of the shelf. In the central area between the two upwellings, 'Banc -water' extended from the shelf into the ocean. The possible impact of the observed circulation of ocean water on productivity of the shelf benthic system is discussed.