The fate of cetacean carcasses in the deep sea: observations on consumption rates and succession of scavenging species in the abyssal north-east Atlantic Ocean

Abstract

The fate of cetacean carcasses in the deep sea was investigated using autonomous deep-sea lander vehicles incorporating time-lapse camera systems, ¢sh and amphipod traps. Three lander deployments placed cetacean carcasses at depths of 4000^4800 m in the northeast Atlantic for periods of 36 h, 152 h and 276 h before being recovered. The photographic sequences revealed that carcasses were rapidly consumed by ¢sh and invertebrate scavengers with removal rates ranging from 0.05^0.4 kg h 71. In the longest experiment the carcass was skeletonized within ¢ve days. In each deployment, approximately an hour after emplacement, the grenadier Coryphaenoides (Nematonurus) armatus and large numbers of lysianassid amphipods had arrived at the food-fall. The initially high numbers of grenadiers declined once the majority of the bait had been consumed and a variety of other ¢sh and invertebrates were then observed, some taking up residence at the site. None of the ¢sh species appeared to consume the carcass directly, but preyed upon amphipods instead. Funnel traps recovered with the carcass indicated a succession in the species composition of amphipods, with the specialist necrophages such as Paralicella spp. being replaced by more generalist feeders of the Orchomene species complex.

Trends in body size across an environmental gradient: A differential response in scavenging and non-scavenging demersal deep-sea fish

“…Lampitt et al (1986) showed a logarithmic decline in megabenthos biomass from 800 to 4100 m in the PSB, which is a proxy for predator food availability. The distribution of carrion is not so well described (Stockton & Delacca 1982;Jones et al 1998;Smith & Baco 2003), but is likely to decline with distance from shore and hence, usually with depth. Consequently, the relative selective pressures for swimming speed, nutrient storage and metabolic economy will differ greatly between scavengers and non-scavengers, even when these species are closely related (note that the four species of Coryphaenoides show positive, negative and no relationship with depth; figure 3).…”

On the role of bone-eating worms in the degradation of marine vertebrate remains

“…These hypotheses are supported by recent studies of small marine vertebrate remains. Two porpoises and a dolphin, weighing between 50 and 100 kg and placed directly on the seabed at 4800 m in the Porcupine Abssyal Plain were studied over a period of 1-12 days by time-lapse camera ( Jones et al 1998). Although the duration of the experiment was almost certainly too short for Osedax to have had time to settle, the limited skeletal remains after just 12 days on the seabed, and the likelihood of many of the small bones being scavenged or settling into the sediment, suggests that there would be little available bone material left after three to four weeks.…”

New method for presenting nutritionally defined food sources to marine organisms

“…However, previous studies have sought to investigate the response of scavengers in the deep sea to food falls, in the form of animal carcasses, rich in protein and lipids, or plant and algal material comprised of protein and carbohydrates (Gooday and Turley 1990;Klages et al 2002;Jones et al 1998;Priede et al 1994). There are currently two approaches to studying these food falls.…”