Hydrographical characteristics and zooplankton distribution in the Mallorca channel (Western Mediterranean): spring 2001

The distribution of zooplankton in the upper 100m of the Mallorca channel (Balearic Sea) was investigated during the spring of 2001 and related to the main hydrographic parameters. Synoptic satellite images were examined and 29 stations were sampled by means of oblique hauls. The sea surface temperature, salinity, and chlorophyll a in the channel show the existence of a hydrological front related to the composition of phyto- and zooplankton. The main zooplankton groups revealed a horizontal distribution pattern related to the hydrographic features of the area. The highest zooplankton abundance, mainly due to copepods (78% of the total zooplankton), was found where the coolest and more saline waters were observed, i.e. in the northern part of the channel. The lowest abundance, mainly represented by siphonophores, chaetognaths, and doliolids, was in the south in the warmer and less saline waters, indicating the input of Atlantic waters into the channel. The spatial distribution of the main species and zooplankton groups was also examined in relation to the frontal system, suggesting their function as biological indicators of the upper water hydrography in the Balearic Sea (Western Mediterranean). (C) 2004 International Council for the Exploration of the Sea. Published by Elsevier Ltd. All rights reserved.