Interactions between seabirds and sharks at a fur seal carcass

The transfer of nutrients and energy from carcasses to scavengers is an important ecosystem function. In marine ecosystems, mammal carcasses can represent a spatiotemporally restricted but substantial pulse in resource availability, as they are typically only briefly available to scavengers on the surface. Little is understood about how these scavengers respond to such pulses, or how inter-scavenger interactions may influence their behaviour. We describe scavenging interactions of procellariiform seabirds at a fresh and floating New Zealand Fur Seal Arctocephalus forsteri carcass, recently killed by a White Shark Carcharodon carcharias, over the continental slope of southeastern Australia. We highlight potential exclusive and facilitative interactions between the shark and various seabirds, which may play an important role in energy-transfer dynamics in surface pelagic environments. We also provide apparently novel descriptions of scavenging at a marine mammal carcass for six of the seven seabird species that attended the carcass. Further study of sea-surface scavenger behaviour, interactions, and ecology will provide valuable insights into energy-transfer dynamics in pelagic ecosystems.