Model suitable and you may diagnostics
We fit our Bayesian state-space model, consisting of both movement and observation process components, using Markov chain Monte Carlo (MCMC) methods. We assigned uninformative priors whenever there were no a priori expectations about the relationships of the model parameters and the movement behavior states (see Appendix S1). n,t) within each iteration of the MCMC algorithm (see Appendix S2). We initialized six chains from random starting values drawn from the prior distributions. After initial pilot tuning and burn-in, we ran the chains until the univariate Gelman–Rubin potential scale reduction factor (PSRF) for monitored parameters was <1.2 and effective sample sizes exceeded 4000. This required about 6 million iterations per chain, where 1 million iterations for each parallel chain required about 100 h using six cores of a 3.7-GHz processor. Data and code can be found in Data S1.
Performance
Predicated on posterior settings to own condition assignments, we discover these bearded seals spent 70% of its deployment episodes about benthic foraging condition (B). They hauled from frost (state I) and you can rested in the sea (condition S) for the about equivalent size, but there can be a very clear regular parts inside interest spending plans certainly brand new hauled on freeze (I), benthic foraging (B), and you can transportation (T) claims you to coincided on the june retreat and you can wintertime get better of sea freeze in the Snowy (Dining table dos). Most of the seals displayed rigorous benthic foraging over the continental cabinets of this new Chukchi otherwise Beaufort waters since water freeze receded northward during the the summertime. I located little www.datingranking.net/local-hookup/manchester or no proof of these frost-associated seals pulling out on house, though near the coastline inside the largely freeze-totally free months in the summertime. Remarkably, a grown-up men temporarily gone north of your Beaufort coastal shelf when you look at the later and you can are predicted to own hauled on new falling out in clumps ocean freeze edge ranging from bouts away from middle-drinking water foraging about greater oceans of the Canada Basin (Fig. 2). We provide reveal cartoon of predict actions and you may state projects for everyone seals in accordance with bathymetry and you can ocean ice defense during the Appendix S3.
- There have been seasonal differences in hobby spending plans between “summer” (out of tagging in late Summer and you may early July so you’re able to 31 Sep), “autumn” (step 1 Oct to 30 December), and “winter” (step one January up until level loss anywhere between February and you will April) you to coincided into the south get better out-of winter months water ice in the brand new Cold. Craft budget information was indeed calculated based on the posterior mode of day spent when you look at the for every condition that have straight down (LCI) and higher (UCI) credible periods considering 95% high rear density. Personal seal interest costs are included in Appendix S4.
As expected, the resting states (I, S, and L) exhibited shorter step lengths, no directional persistence, and lower proportions of each time step diving >4 m below the surface based on state-specific parameter estimates (Fig. 3; see Appendix S4 for posterior sumeters). Both the mid-water foraging (M) and transit (T) states exhibited longer step lengths, lower proportions of dry time, and higher proportions of diving >4 m below the surface. Only the transit state exhibited strong directional persistence, but state M exhibited moderate directional persistence for some individuals (Fig. 3). The benthic foraging (B) state generally exhibited moderate step lengths, no directional persistence, lower proportions of dry time, higher proportions of diving >4 m below the surface, and considerably higher benthic dive counts (posterior median for ?B = 41.4; 95% highest posterior density interval: 41.2–41.7). The resting (?I = ?S = ?L = 9.7; 95% HPDI: 9.4–10.0) and transit (?T = 15.0; 95% HPDI: 14.5–15.5) states exhibited moderate benthic dive counts, while the mid-water foraging state generally had the lowest benthic dive counts (?M = 1.5; 95% HPDI: 1.3–1.7; Fig. 3). The moderate benthic dive counts for the resting and transit states could be attributable to mid-interval state switches, but there certainly could have been opportunistic benthic foraging during transit. There also could have been high-speed, directionally persistent benthic dives while transiting in relatively shallow shelf waters.