Bathymetric distribution of some benthic and benthopelagic species attracted to baited cameras and traps in the deep eastern Mediterranean

A series of baited camera and trap experiments in the eastern Mediterranean Sea between 1500 and 4264 m depth attracted a variety of opportunistic scavengers, with species composition changing with increasing depth. At the shallower stations (1500 to 1800 m), decapod crustaceans and fishes, dominated by elasmobranchs such as Hexanchus griseus, were attracted to and actively consumed the bait. Some of these species were observed at depths exceeding their previously reported ranges. This was believed to be a result of the absence of deep-water scavengers from the adjacent Atlantic due to dispersal barriers and elevated temperatures at depth. The diversity of bait-attending fauna declined with increasing depth. Elasmobranchs were not observed below 2500 m, and below 4000 m only the caridean shrimp Acanthephyra eximia and the macrourid Chalinura mediterranea were present; at this latter depth, bait consumption was negligible. This shift in species composition was reflected in changes in first arrival times. Increasing first arrival times of H. griseus suggested a decline in relative abundance from 1500 to 2500 m, whilst those of C. mediterranea indicated an increase in relative abundance from 1800 to 4264 m.