SPRING ZOOPLANKTON DISTRIBUTION AND PRODUCTION OF THE COPEPOD EUTERPINA ACUTIFRONS IN MARENNES-OLERON BAY (FRANCE)

Short term variations of zooplankton populations were studied during a n algal spring bloom in two characteristic areas of the Marennes-Olero n Bay (France). The sampling sites were chosen in the north of the bay , one close to the neritic zone, the other close to the estuarine zone . Five distinct zooplanktonic communities were observed: two typical n eritic and estuarine assemblages, two eurytopic groups (linked to neri tic or estuarine water masses) and an autochtonous community, widely d istributed in the north of the bay. The copepod Euterpina acutifrons d ominated the zooplankton community during this period of the year in t erms of abundance (up to 83% of the zooplankton community). Its produc tion differed between water masses: the highest production occurred at the estuarine station (3.48+/-0.65 mg C m(-3) d(-1)), where nauplii a ccounted for a large part of these high values. Its P/B ratio was simi lar at the two stations (0.196 and 0.209 d(-1)).