Multi-predator feeding aggregations in pelagic waters

Abstract Multi-predator feeding aggregations (MPFAs) are temporary co-occurrences of several species of predators simultaneously exploiting the same prey resource. Pelagic waters are home to the largest and most diverse MPFAs on the planet, however, our knowledge of the mechanisms and functions driving the existence of MPFAs is heavily biased towards terrestrial systems which are characterized by the fight for resource monopolization. By contrast, in pelagic waters, observed interactions between predators rarely involve aggression, presumably because monopolization of large fish schools or zooplankton swarms is difficult or impossible. Additionally, the provision and maintenance of energetically viable prey aggregations may depend on conspecific and heterospecific hunting behaviour. There has been considerable speculation regarding the interactions of predators in pelagic MPFAs, which include sharks, teleost fishes, seabirds, pinnipeds and cetaceans, but these interactions are difficult to observe in situ. Only recently have scientists begun to obtain data on attack and capture rates of predators at pelagic MPFAs which allow insights into whether their interactions are competitive, mutualistic or neutral. In this special edition, we begin by outlining the biomechanical and energetic bases of MPFAs before probing some of the main hypotheses regarding predator interactions at MPFAs. We then address MPFAs from a collective behaviour perspective before ending with some of the broader ecological aspects of MPFAs. Links between MPFAs and socio-economic factors such as marine reserves, sustainable fisheries and eco-tourism practices are discussed throughout the issue's 14 articles. This article is part of the theme issue ‘Multi-predator feeding aggregations in pelagic waters’.