MEPS 424:145-156 (2011)  -  DOI: https://doi.org/10.3354/meps08972

ABSTRACT: Baited cameras have offered much insight into the ecology of scavenging animals in several parts of the worlds’ oceans, revealing patterns of vertical zonation, trends in size and abundance with depth, and aspects of feeding behavior. It is surprising, then, that very little has been published on the scavenging community off the eastern Pacific continental slope, where work of this nature originated. Here we present a study of megafaunal scavenger ecology encompassing a wide range of taxa from shelf to abyssal depths off central California. During 13 baited camera deployments from 105 to 3144 m, we photographed 25 scavenging taxa, consisting mainly of fish and crabs. Combined with trawl results, these data showed that prevalence of scavenging in fishes increased from 2% of all species at 100 m to 46% of all species at 3000 m, suggesting more opportunistic feeding habits and the increasing importance of carrion as a food source at greater depths. Of 4 scavenging fish species examined, 3 (Antimora microlepis, Albatrossia pectoralis, and Anoplopoma fimbria) displayed significant increases in length with increased depth while Coryphaenoides acrolepis displayed an opposite, ‘smaller-deeper’ trend. Estimates of fish density generated from camera first arrival times and trawl data were compared, yielding no significant correlation. During one camera deployment, C. armatus was used as bait, which resulted in the complete absence of C. armatus, while a peak abundance of 11 individuals was observed at similar depths/locations using non-macrourid bait. The depth-related patterns in scavenger species richness and intraspecific size-depth trends differ from those in the North Atlantic, suggesting that further regional comparisons are needed to better understand scavenger ecology on a global scale.

KEY WORDS: Scavenger · Deep sea · Size trends · Abundance estimate · Baited camera