Estimating the Effect of Groundfish Abundance and Other Spatial Covariates on Northern Fur Seal Behavior

• Activity Number: 645
• Type: Contributed
• Date/Time: Thursday, August 8, 2013 : 8:30 AM to 10:20 AM
• Sponsor: Section on Statistics and the Environment
• Author(s): Ruth Joy*+ and Rick Routledge
• Companies: Department of Statistics, SFU. and Department of Statistics, SFU.
• Keywords: northern fur seals ; behaviour ; bayesian ; foraging ; state-space model ; hierarchical

Abstract

The population of northern fur seals in the Pribilof Islands, Alaska has declined dramatically during the past 35 years. Arresting the decline of the species requires an understanding of their foraging behaviour at-sea and its link to pup survival. We propose an augmented state space methodology for studying behavioural patterns using high resolution movement time series. This framework allows us to relate the time-varying parameter estimates of an auto-regressive system model to the seal's at-sea behavior. The at-sea behaviour states of 11 seals were then matched, spatially and temporally, to a set of environmental variables, some of which were averages that represented the oceanic conditions over a large spatial area. The mismatch of scale between seal behaviour and the spatial variables was accounted for by using an error-in-covariate Bayesian hierarchical model.