Abstract
Through a combination of methodology refinement and development of novel and innovative approaches, we will develop the analytical tools needed to estimate the impact of marine predators on fish stocks and the effects of variations in foraging success on the condition of the predators themselves, with greater accuracy. While the proposal focuses on the Northeast Atlantic harp seal (Pagophilus groenlandicus), the methods developed here will have wide application to the study of energetics and prey composit ion of top trophic marine vertebrates in a range of ecosystems. The approach is based on continuous real-time monitoring of energy expenditure, body composition, prey capture rates and diet composition of individuals while at sea. It relies on combining a nimal-borne acceleration and camera data loggers, and focuses on the development of novel and innovative approaches for deriving indices of energy expenditure, prey capture and diet composition from these instruments. This requires detailed studies of ene rgy expenditure, swimming and diving behaviour and prey capture in a captive controlled setup, in combination with developing an underlying bioenergetic model to be used to determine energy allocation and changes in condition from acceleration data. We wi ll also develop indices of prey capture events from acceleration data, capable of triggering the camera at times of interest. In order for the next-generation animal-borne instrument to relay relevant indices in real-time via limited bandwidth satellite s ystems, the high-volume data provided by accelerometers and cameras will have to be compressed into simple energy expenditure and prey classification indices. This study will lay the necessary groundwork by providing such indices for energy expenditure, a nd by initiating the collection of known-species prey images that can be used for subsequent development of appropriate object detection and classification algorithms.
Norway