Relationships between shallow-water cumacean assemblages and sediment characteristics facing the Iranian coast of the Persian Gulf

During two sampling campaigns carried out in August 1998 and November 2002, 232 cumeaeans from eight species belonging to the families Bodotriidae and Nannastacidae were collected. This paper presents the first ecological data on a shallow water tropical cumacean assemblage from the Persian Gulf where 5096 of the existing species were recently described as new for the science. Neither the environmental conditions (except for the sediment organic content) nor the cumacean assemblage descriptors differed between the two sampling periods. However, two different species dominated in each period (i.e. Eocuma travancoricum and Heterocuma inerme in 1998 and 2002, respectively) and the MDS analysis revealed differences in the assemblage composition between periods, particularly Or the deepest sampling stations. An increasing density together with the increase in gravel content, and a decreasing density together with the increasing silt content characterized the distribution pattern of both the whole cumacean assemblages and the two dominant species, the latter being also positively correlated with the mean grain size and negatively correlated with depth and organic matter (E. travancoricum) and with depth (H. inerme).