Intertidal habitats and decapod (Crustacea) diversity of Qeshm Island, a biodiversity hotspot within the Persian Gulf

Abstract

Qualitative rapid assessments and taxonomic surveys of decapod crustaceans were carried out along the entire coastline of Qeshm Island in the Persian Gulf. Shore morphology and habitat distribution were examined. Simultaneously, decapod samples were collected from 40 selected sites. In total, 131 species from five different infraorders were identified, of which 61 were recorded for the first time from Qeshm Island and 18 species were new records for the Persian Gulf. The Brachyura possessed the highest species richness (73 species, 56 %) within the different infraorders. Among the surveyed habitats, the combined habitat “rocky/cobble”, occurring mainly along the south coast, had the highest species diversity. Rocky shores were dominated by Grapsus albolineatus, Metopograpsus messor, and Eriphia smithii. Cobble beaches were dominated by Leptodius exaratus, Epixanthus frontalis, Clibanarius signatus, Nanosesarma sarii, Petrolisthes spp. and Alpheus lobidens. Mudflats and mangrove forests, typical habitats of the north coast of Qeshm Island, were bordered along their landward fringe with Nasima dotilliformis and Uca sindensis, which were accompanied by Uca iranica in some places with coarser sediments. On muddy substrate and among mangroves, Metopograpsus messor, Parasesarma persicum, Eurycarcinus orientalis, Macrophthalmus depressus, Metaplax indica, Ilyoplax stevensi, Manningis arabicum, Opusia indica and Alpheus lobidens were the most common species. Exposed sandy beaches, mainly found on the south coast, were inhabited by Ocypode rotundata and Coenobita scaevola in high-intertidal and supralittoral zones, respectively. Emerita holthuisi occurred slightly lower in the mid-intertidal zone of relatively steep beaches where Diogenes avarus and Ryphila cancellus were found whenever the sandy beach was relatively flat. Intertidal habitats of the island are generally in relatively good condition compared with the other Persian Gulf states.