Zooplankton composition, distribution and abundance in the Bay of Biscay and adjacent Atlantic waters from a cetacean sighting survey

Abstract

In 1989 a Spanish shipboard sighting survey was carried out as part of a combined international cetacean's survey in the North Atlantic ( NASS-89). The cruise had taken place during July- August covering the Bay of Biscay and adjacent Atlantic waters between 42º- 52º N and 25º W. Zooplankton samples obtained during that cruise have recently being processed and analysed. Due to the relative scarce information available about the zooplankton of the area surveyed it was considered useful to present now this information. Data about the composition, distribution and abundance of the zooplankton fraction between 200 μm and 2 mm were obtained. The dominant groups in the oceanic area were Acantharia, Radiolaria and Amphipoda. In some stations these groups represented more than 50% on the plankton community. In the Bay of Biscay, apart from the groups found in the oceanic area, they also appeared Doliolida and the copepod Calanoides carinatus (Krøyer, 1848). Abundances had range between 2 and 27 785 ind. m-3 due to the wide extension and different thermohaline characteristics of the area sampled. The groups with more than 500 ind. m-3 were the Radiolarian, Acantharia, Chaetognatha and the copepod Calanoides carinatus. The last two groups were more abundant in the coastal zone.