Tracking Bearded and Ringed Seals in Svalbard

Prototype Satellite Relay Data-Loggers (SRDLs, Sea Mammal Research Unit, University of St Andrews, Scotland) were attached to six adult female bearded seals (August 2011 N = 4; August 2012 N = 2) and 10 adult female ringed seals (August 2012 only), in Svalbard Norway. Programming details for telemetry devices are outlined in Supplementary Materials. All research activities including both animal care and field site permitting during this study were approved and carried out under permits from the Norwegian Animal Care Authority (Forsøksdyrutvalget ref. 2010/45416 and 2011/42085) and the Governor of Svalbard (Sysselmannen på Svalbard Ref. 2011/00488-52). In addition to the standard sensors for measuring dive data, each SRDL contained an Argos-linked Fastloc GPS transmitter. All tags were programmed to the same specifications (S1 File), and the default speed parameter was used for the Argos Kalman filtering process (10ms^-1). We are unaware of any other speed parameter setting being used in the marine mammal research community, and can thus not comment on the effects of varying this threshold with respect to the outcome of the Argos SRUKF process. Capturing and handling of these animals was conducted using the same methods as those outlined in [21 (link)]. Argos locations are derived as a by-product of all messages transmitted from the SRDL to the satellite system, while transmitted GPS data consist of a random subset of locations collected by the Fastloc GPS receiver on the animal, resulting in temporally decoupled Argos and GPS positions. Calibration studies of Fastloc GPS data show errors (at the 95^th percentile level) between 24.2 m and 140 m for locations estimated by eight and five satellite acquisitions, respectively [22 ]. We removed all GPS locations with less than five satellite acquisitions, and henceforth assume the remaining GPS locations reflect the true position of the animal [23 (link)].