Estimation and simulation of foraging trips in land-based marine predators

• Published in: Ecology
• Main Authors: Michelot, Theo, Langrock, Roland, Bestley, Sophie, Jonsen, Ian D., Photopoulou, Theoni, Patterson, Toby A.
• Other Authors: University of St Andrews.School of Mathematics and Statistics, University of St Andrews.School of Biology, University of St Andrews.Centre for Research into Ecological & Environmental Modelling
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2018
• Subjects: Animal telemetry; Central place foraging; Hidden Markov model; Mirounga leonina; Southern elephant seal; QH301 Biology; DAS; SDG 14 - Life Below Water; QH301; Southern Ocean; Kerguelen; Kerguelen Island; Elephant Seal; Elephant Seals; Southern Elephant Seal; Southern Elephant Seals
• Online Access: https://hdl.handle.net/10023/13114; https://doi.org/10.1002/ecy.1880

TM and TP received support from IMBER-CLIOTOP and Macquarie University Safety Net Grant 9201401743. SB was supported under an Australia Research Council Super Science Fellowship. IDJ was supported by a Macquarie Vice-Chancellors Innovation Fellowship. TAP was supported by a CSIRO Julius Career Award and the Villum Foundation. The behavior of colony-based marine predators is the focus of much research globally. Large telemetry and tracking data sets have been collected for this group of animals, and are accompanied by many empirical studies that seek to segment tracks in some useful way, as well as theoretical studies of optimal foraging strategies. However, relatively few studies have detailed statistical methods for inferring behaviors in central place foraging trips. In this paper we describe an approach based on hidden Markov models, which splits foraging trips into segments labeled as "outbound", "search", "forage", and "inbound". By structuring the hidden Markov model transition matrix appropriately, the model naturally handles the sequence of behaviors within a foraging trip. Additionally, by structuring the model in this way, we are able to develop realistic simulations from the fitted model. We demonstrate our approach on data from southern elephant seals (Mirounga leonina) tagged on Kerguelen Island in the Southern Ocean. We discuss the differences between our 4-state model and the widely used 2-state model, and the advantages and disadvantages of employing a more complex model. Peer reviewed