Spatial and temporal variation of echinoderm assemblages from soft bottoms of the Çanakkale Strait (Turkish Strait System) with a taxonomic key of the genus Amphiura (Echinodermata: Ophiuroidea)

Th is study deals with the structure of echinoderm assemblages and their relationships with the biotic and abiotic conditions in the Çanakkale Strait in 2006 and 2007. A total of 25 echinoderm species were found, 4 species of which [Amphiura securigera (Düben Koren, 1846); Amphiura lacazei Guille, 1976; Amphiura cherbonnieri Guille, 1972; and Th yone fusus (O.F. Müller, 1776)] were new records for Turkish fauna; 1 species [Ophiopsila annulosa (M. Sars, 1859)] was new for the Turkish Strait System; and 22 species were fi rst reports for the Çanakkale Strait. Echinocyamus pusillus (O.F. Müller, 1776), Amphipholis squamata (Delle Chiaje, 1829), and Ophiothrix fragilis (Abildgaard, 1789) were the most important species, representing 71% of the total abundance. Ophiuroids were found to be the dominant group, but asteroids also played a signifi cant role in the echinoderm community structure. No seasonal diff erences were found, while fi ner sediments and the percentage of organic carbon (TOC) seemed to encourage echinoderm behavior. Hydrodynamism seems to be the factor regulating benthic assemblages’ structure and distribution in the Çanakkale Strait. An identifi cation key to the Mediterranean species of the genus Amphiura is provided.