Through the eyes of a penguin: Estimating krill densities using animal-borne video loggers
Antarctic krill (Euphausia superba) are a keystone species in the Southern Ocean and if their populations decline there could be detrimental impacts to many other species in the Antarctic ecosystem. In order to study krill, the National Oceanic and Atmospheric Administration (NOAA) regularly monitors the Antarctic ecosystem, including outfitting predators with cameras to record prey encounters during feeding events. NOAA also recently sponsored the development of an open-source underwater imagery analysis system called Video and Image Analytics for a Marine Environment (VIAME) in order to make automated methods to process mass amounts of underwater visual data accessible to analysts and non-computer scientists. The proposed work of this study will use the VIAME software to determine the volumetric densities of krill observed in a video recording during a chinstrap penguin foraging event from the 2018 field season. The methods developed by this study resulted in imaged volume based on the maximum resolvable range, counts of krill per volume, and subsequently densities of krill. These methods provide a basis for automatically processing and estimating densities of krill pursued and encountered by predators. Densities from the perspective of a predator have not been documented previously for the Antarctic ecosystem.