Locomotion and hunting strategies of large vertebrate predators in pelagic waters.

Many of the key dynamics that shape predator-prey interactions are governed by the physical and physiological principles which determine how animals move and perform in their environments. This opinion paper outlines the foundations underlying marine vertebrate predator-prey encounters within the context of pelagic habitats. Variables, such as maximum swimming speed, acceleration and manoeuvrability, play crucial roles in dictating the outcome of predator-prey encounters. In pelagic areas, sustainable swimming speed is an additional factor that can play an important role when chases occur. These locomotor traits are, in turn, influenced by body size, morphology and physiology. For predator-prey size ratio between 10 and 100, predators resort to a number of alternative strategies in order to overcome the elusiveness of the prey resulting from their higher manoeuvrability. These include pursuit leading to prey exhaustion, group hunting and the use of weapons. The framework of how physiological, physical and scaling rules affect pelagic predator-prey systems is a useful tool for investigating multi-predator feeding aggregations, where the relative success and potential competition between each predator species will be dictated by the potential strategies available to them within the scope of their performance limits. This article is part of the theme issue 'Multi-predator feeding aggregations in the pelagic waters'.