Movement patterns and activity levels are shaped by the neonatal environment in Antarctic fur seal pups

Tracking studies of juveniles are rare compared to those of adults, and consequently little is known about the influence of intrinsic and extrinsic factors on activity during this critical life stage. We used hourly GPS data, collected from 66 Antarctic fur seal pups from birth until moulting, to investigate the explanatory power of multiple individual-based and environmental variables on activity levels. Pups were sampled from two nearby breeding colonies of contrasting density during two subsequent years, and a two-state hidden Markov model was used to identify modalities in their movement behaviour, specifically ‘active’ and ‘inactive’ states. We found that movement was typified by central place exploration, with active movement away from and subsequent return to a location of inactivity. The probability of such directed exploration was unaffected by several factors known to influence marine mammal movement including sex, body condition, and temperature. Compared to pups born at the high-density colony, pups at low-density were more active, increased their activity with age, and transitioned earlier into the tussock grass, which offers protection from predators and extreme weather. Our study illustrates the importance of extrinsic factors, such as colony of birth, to early-life activity patterns and highlights the adaptive potential of movement.

Movement patterns and activity levels are shaped by the neonatal environment in Antarctic fur seal pups

Tracking studies of juveniles are rare compared to those of adults and consequently, little is known about the influence of intrinsic and extrinsic factors on activity during this critical life stage. We therefore collected GPS data from birth until moult from 66 Antarctic fur seal pups in two nearby but contrasting breeding colonies. The Special Study Beach (SSB) is a high-density colony separated from the inland tussock grass habitat by a steep gully, whereas Freshwater Beach (FWB) is a low-density colony that is topographically more open. We investigated the explanatory power of multiple individual-based and environmental variables using a hidden Markov model. We found that activity was typified by central place exploration, with directed movement away from and subsequent return to a location of low activity. The probability of such directed exploration was unaffected by several factors known to influence marine mammal movement including sex, body condition and temperature. Conversely, FWB pups were more active, increased their activity with age and transitioned earlier into the tussock grass, which offers protection from predators and extreme weather. Our study illustrates the profound importance of extrinsic factors to early movement and highlights the adaptive potential of movement in the face of environmental variability.

Isolation and genome sequencing of Staphylococcus schleiferi subspecies coagulans from Antarctic and North Sea seals

Reports on the commensal organism and opportunistic pathogen Staphylococcus schleiferi have largely considered isolates from humans and companion dogs. Two subspecies are recognized: the coagulase-negative S. schleiferi ssp. schleiferi, typically seen in humans, and the coagulase-positive S. schleiferi ssp. coagulans, typically seen in dogs. In this study, we report the isolation, genome sequencing and comparative genomics of three S. schleiferi ssp. coagulans isolates from mouth samples from two species of healthy, free-living Antarctic seals, southern elephant seals (Mirounga leonina) and Antarctic fur seals (Arctocephalus gazella), in the South Orkney Islands, Antarctica, and three isolates from post-mortem samples from grey seals (Halichoerus grypus) in Scotland, UK. This is the first report of S. schleiferi ssp. coagulans isolation from Antarctic fur seal and grey seal. The Antarctic fur seal represents the first isolation of S. schleiferi ssp. coagulans from the family Otariidae, while the grey seal represents the first isolation from a pinniped in the Northern Hemisphere. We compare seal, dog and human isolates from both S. schleiferi subspecies in the first genome-based phylogenetic analysis of the species.