Animal-borne video highlights diverse prey capture tactics and habitat use in the Australian sea lion

Abstract

Understanding the foraging ecology of predators is critical to identifying the resources and habitats that maintain their populations and is essential for their conservation and management. For marine predators that spend extended periods at sea and underwater, the use of animal-borne video provides a novel method of observing individuals in their environment and the foraging behaviours they employ. The endemic Australian sea lion, Neophoca cinerea, is listed as endangered, with its populations declining by more than 60% over the last 40 years. Due to the highly subdivided genetic structure of Australian sea lion populations, an intimate understanding of their foraging behaviour, throughout their distribution, is needed to support targeted management at the breeding site level. Here, we use animal-borne video collected from 10 adult female Australian sea lions from five colonies in South Australia to identify the prey capture tactics they use across different benthic habitats. We identified a variety of prey capture tactics (probing, chasing, pelagic ambushing of schooling fish, flipping rocks/substrate and sit-and-wait predation), exploiting a range of benthic habitats, including seagrass meadows, bare sand plains and macroalgae reefs, while hunting diverse prey, such as benthic/epibenthic fishes, cephalopods and elasmobranchs. The prey capture tactics most frequently observed were probing and chasing, which were used by all individuals, whereas flipping rocks, sit-and-wait predation and pelagic ambush were less frequent. Using specialist prey capture tactics, such as sit-and-wait predation, may increase the capacity of sea lions to exploit a greater diversity of prey and benthic habitats, which could increase their overall success and fitness. This study underscores the significance of animal-borne video as a crucial tool for identifying and mapping the critical habitats and resources essential for Australian sea lions.