Design installing and you can 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). letter,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.
Centered on rear settings getting state projects, we found such bearded seals invested 70% of its implementation attacks about benthic foraging condition (B). They hauled from frost (state I) and rested at the ocean (condition S) in around equivalent dimensions, however, there can be a definite regular component from inside the craft spending plans among new hauled on frost (I), benthic foraging (B), and you may transit (T) claims one to coincided towards the summer haven and you can cold temperatures get better from ocean ice in the Arctic (Desk 2). All the seals shown intensive benthic foraging over the continental cupboards off the fresh new Chukchi or Beaufort seas because sea frost receded northward into the the summer. We discovered very little proof these types of frost-associated seals pulling from residential property, regardless of if close to the coast during the mainly ice-free months in the summer. Surprisingly, a grownup male briefly moved northern of your own Beaufort coastal shelf during the later and you can is forecast to have hauled out on this new falling out in clumps sea ice edge ranging from bouts off middle-liquid foraging throughout the deeper seas of Canada Basin (Fig. 2). We provide an in depth animation away from predicted movements and you may condition tasks for everybody seals according to bathymetry and you can water freeze cover within the Appendix S3.
- There had been regular differences in hobby finances between “summer” (away from marking inside the later June and very early July so you can 31 September), “autumn” (step 1 October to help you 31 December), and you will “winter” (1 January up until level losings ranging from March and you can April) one coincided on southern improve off winter months water frost in the fresh Cold. Hobby finances explanations had been computed based on the rear form out-of big date spent when you look at the for each and every state having all the way down (LCI) and you can top (UCI) reputable menstruation centered on 95% large posterior density. Individual seal craft budgets are part of 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 hookup dating in Tulsa = ?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.