The benthic Gammaridea (Crustacea, Amphipoda) fauna of Algeciras Bay (Strait of Gibraltar):: distributional ecology and some biogeographical considerations

The Gammaridea fauna of Algeciras Bay, located on the Mediterranean side of the Strait of Gibraltar, was studied with regard to the species composition, distribution and ecology. Of the 116 species identified, 13 are recorded for the first time along the Iberian Peninsula coast, 30 for the Spanish coast and 78 for the Andalusian coast. Two species, Apherusa bispinosa (Bate 1857) and Idunella nana (Schiecke 1973), were collected for the second time in the Mediterranean Sea; this represents the first record of I. nana since its original description. The abundances of the various species and their distribution in terms of bathymetry and type of substrate were analysed, as was the enlargement of the distributional range of some species in the Mediterranean Sea. With regard to biogeographical distribution, Algeciras Bay can be considered a typical Mediterranean locality despite being situated in the Strait of Gibraltar. This is in agreement with previous studies on the amphipod fauna of the Portuguese coast.