Consumption of large carcasses by scavenger assemblages in the deep Arabian Sea: observations by baited camera

During cruise no. 118 with RV 'Sonne' to the Arabian Sea (31 March to 10 May 1997), 2 large food fall experiments were carried out in order to study the composition of the scavenging fauna of the deep western Arabian Sea. Two shark carcasses were deployed at the sea floor at 4040 and 1900 m depth and monitored by a time-lapse camera for 11 and 5 d, respectively.. At 4040 m, zoarcid fish dominated during the whole deployment period, accompanied by decapod shrimp. Decapods reached the carrion within 20 min, and during the period monitored 1 to 4 decapods regularly occurred on or near the carcass. Single zoarcids were first observed after 5 h, their number rising to 50-60 during the initial 48 h, then remaining constant at this level. At 1900 m, 3 individually identifiable deepsea stone crabs were alternately feeding on the shark carcass for most of the observation period. Fish appeared rarely and never stayed at the carcass for long. Most strikingly, giant scavenging amphipods were not observed at 1900 m and macrourids were not observed at 4040 m. Not more than 20 % of the carrion was consumed at both stations.