Résultats biologiques de la campagne Polymède IV. - Micronecton en Méditerranée occidentale et proche Atlantique : données quantitatives et comparaisons

The authors study and compare the biovolumes of 69 samples collected with an Isaacs-Kidd trawl during the Polymède cruise of the R.V. Jean Charcot (May and June 1970) in the eastern Mediterranean Sea and around the Cap Finisterre. Based on these quantitative bases, along the 5° East meridian, two basins can be distinguished in the eastern Mediterranean Sea: - one located north of the Balearic insular arc, - the other located south of the same arc. The comparison between these two basins shows a greater "richness" of the northern area. This is especially remarkable for Euphausiacea (ratio of 1 to 30). At this time of the year and at this trophic level, no specific influence of the North-African Atlantic current can be found. A similar sample collection off the Cap Finisterre enabled the comparison of this Atlantic area with the Mediterranean basins. As a consequence, it appears that the different taxonomic units have a more distinct bathymetric zonation in the Atlantic Ocean. In addition, the different biovolumes collected in both seas remained similar.