Seasonal home ranges and fidelity to breeding sites among ringed seals

Abstract

Population structure and patterns of habitat use among ringed seals (Phoca hispida) are poorly known, in part because seasonal movements have not been adequately documented. We monitored the movements of 98 ringed seals in the Beaufort and Chukchi seas between 1990 and 2006 using three forms of telemetry. In the winter-spring period (when the seals were occupying shorefast ice), we used radio and ultra-sonic tags to track movements above and below the ice, respectively. We used satellite-linked transmitters in summer and fall (when the seals ranged away from their winter sites) to track at-sea movements. In the shorefast ice habitat, the home ranges of 27 adult males ranged from \1 to 13.9 km 2 (median = 0.628) while the home ranges of 28 adult females ranged from \1 to 27.9 km 2 (median = 0.652). The 3-dimensional volumes used by 9 seals tracked acoustically under the ice averaged 0.07 (SD = 0.04) km 3 for subadults and adult males and 0.13 (SD = 0.04) km 3 for adult females. Three of the radio-tracked seals and 9 tracked by satellite ranged up to 1,800 km from their winter/spring home ranges in summer but returned to the same small (1-2 km 2 ) sites during the ice-bound months in the following year. The restricted movements of ringed seals during the ice-bound seasonincluding the breeding season-limits their foraging activities for most of the year and may minimize gene flow within the species.

Individual variation in seasonal movements and foraging strategies of a land-locked, ice-breeding pinniped

“…The active movements of seals over the ice season suggests that unless constrained by breeding or ice conditions they do not spend long periods on the ice sheet and may forage in different locations, supporting observations of females regularly leaving pups on ice to go to sea (Krylov & Vorozhtsov 1972) and observations of significant numbers of lone pups during aerial surveys (Dmitrieva et al 2015). This behaviour contrasts with other ice-breeding species such as ringed seals which show higher levels of site fidelity during breeding since they need to maintain breathing holes during the whole ice period (Kelly et al 2010). Caspian seal surface periods appear similar to other small phocids, e.g.…”

“…Movements of central place foragers (species that make regular short-duration foraging trips to defined feeding areas) can be limited by proximity to haul-out sites, which they use for resting or feeding pups, as seen in harbour seals Phoca vitulina (Thompson & Miller 1990), grey seals Halichoerus grypus (Harvey et al 2012) and otariids during breeding seasons (Thompson et al 2003). Risk of predation (De Vos & O'Riain 2013), interspecies competition (Villegas-Amtmann et al 2013) and physiological state (Kelly et al 2010, Crawford et al 2012) also influence movement patterns and habitat use.…”

Influence of sea ice phenology on the movement ecology of ringed seals across their latitudinal range

“…However, spatial segregation between adults and subadults occurs during the less productive winter and spring breeding season where adult ringed seals establish territories underneath shore-fast ice that are restricted in size (Smith & Hammill 1981), consistent with our results where adults were more likely to be in a resident state than subadults. Subadults inhabit active ice areas to overwinter which are relatively more biologically productive and lack the associated cost of defending underwater territories (Smith & Hammill 1981, Kelly et al 2010.…”

Seasonal Movements and Diving of Ringed Seals, <i>Pusa hispida</i>, in the Western Canadian Arctic, 1999–2001 and 2010–11

“…During the ice-free months, some adults travel considerable distances away from their fast ice breeding habitats in order to feed (Smith, 1987;Heide-Jørgensen et al, 1992;Teilmann et al, 1999;Freitas et al, 2008a), and ringed seals are well known to prey on zooplankton where they are abundant (e.g., Lowry et al, 1978Lowry et al, , 1980Harwood, 1989). There is growing evidence that adults are philopatric, returning annually to the same winter and breeding sites in the fast ice prior to freeze-up in the fall (Smith and Hammill, 1981;Kelly et al, 2010).…”