The East Asian shore crab Hemigrapsus sanguineus (Brachyura: Varunidae) in the Mediterranean Sea:: an independent human-mediated introduction

A single adult male specimen of the East Asian crab Hemigrapsus sanguineus (de Haan, 1835) was collected in August 2001 in the northern Adriatic Sea along the northwest coast of the peninsula of Istra. This is the first record of this genus and species from the Mediterranean Sea. Previously, Hemigrapsus sanguineus had been reported to invade the Atlantic coasts of North America and of western France, while the congeneric East Asian species, Hemigrapsus penicillatus (de Haan, 1835), has established breeding populations along the Atlantic coast of Europe. The current absence of Hemigrapsus sanguineus in southern Europe and the western Mediterranean suggests an independent human-mediated introduction of the Croatian specimen. Preliminary genetic analyses reveal that specimens from Istra, North America, and Japan have identical DNA haplotypes corresponding to the mitochondrial large subunit rRNA gene (16S mtDNA), while the homologous sequence from a specimen of Taiwan differs in two out of 525 nucleotides.