Seasonal presence of ringed, ribbon, and bearded seal vocalizations in the Chukchi Sea north of Barrow, Alaska

Abstract

Long-term autonomous acoustic recordings were collected between September and June from 2006 through 2009 in the Northeastern Chukchi Sea along the continental slope 120 km north of Barrow, Alaska. These recordings were analyzed for the presence of vocalizations of ringed seals (Phoca hispida), ribbon seals (Histrophoca fasciata), and bearded seals (Erignathus barbatus). We present detailed descriptions of the acoustic repertoire of each species in addition to three-year time series of seal vocalizations and mean daily sea ice concentration. Ringed seal vocalizations are present throughout each winter and spring, indicating that they both overwinter and breed in offshore pack ice. Ribbon seal calls occur only during the open water period in 2008, but their acoustic behavior is more varied than previously described. Bearded seal vocalizations closely match well-documented calls recorded offshore near Point Barrow but have shorter duration and smaller frequency range, suggesting that demographic or behavioral differences related to breeding habitat selection may exist within the population. Bearded seal calls peak during the breeding season from March through June, but also occur in December and January annually. These long-term autonomous recordings provide details of seasonal distribution and behavior of Arctic seals that previously have not been possible to observe with other methods.

Seasonal patterns in acoustic detections of marine mammals near Sachs Harbour, Northwest Territories

“…This trend for increased vocalizations during the ice-covered season is relatively consistent with other studies from the Beaufort Sea (MacIntyre et al 2013(MacIntyre et al , 2015, Chukchi Sea Jones et al 2014;FrouinMouy et al 2016), and Baffin Bay (Frouin- Mouy et al 2017;Marcoux et al 2017), although there can be a lot of variation even at a site for seasonal vocalization patterns in this species Frouin-Mouy et al 2016). Although bearded seals vocalize outside of the breeding season, their period of peak vocalizations (24 h/day in this study) occurs between April and June, which not only matched vocalization patterns from other studies (MacIntyre et al 2015;Frouin-Mouy et al 2016) but is also consistent with the timing of their breeding season (Cleator et al 1989).…”

“…Other studies have similarly documented that ringed seals are generally detected throughout the year but are often quiet Jones et al 2014). Ringed seals were less likely to be detected when wind speed increased and when ice concentration increased, although we detected them most when the ice was broken.…”

“…Continuous data on species presence are not possible for other survey methods, such as visual surveys, in the Arctic due to sea ice. Indeed, PAM has been used throughout other areas of Arctic North America for monitoring marine mammals, including the Bering Sea (Moore et al 2006;Munger et al 2008;Stafford et al 2010), western Beaufort Sea (Moore et al 2006;Hauser et al 2017a), Chukchi Sea (Delarue et al 2009;Blackwell et al 2012;Hannay et al 2013;Jones et al 2014;Clark et al 2015;Frouin-Mouy et al 2016), and Baffin Bay (FrouinMouy et al 2017;Marcoux et al 2017), and acoustic monitoring has even been used successfully as a tool for studying the distribution of seals under the ice in the winter (Calvert and Stirling 1985;Cleator and Stirling 1990;MacIntyre et al 2013;Jones et al 2014;Frouin-Mouy et al 2016). …”

Acoustic detections of Arctic marine mammals near Ulukhaktok, Northwest Territories, Canada

“…We set the recorder to record 5 minutes out of every 30 minutes, with a 48 kHz sampling rate, 16-bit depth, and +12 dB of gain. The frequency ranges of vocalizations by ringed seals, bearded seals, and bowhead whales are well within the sampling rate of our recordings (Stirling et al 1983;Tervo et al 2009;Jones et al D r a f t 2014), and also for the communication calls, such as whistles, of beluga whales (Chmelnitsky and Ferguson 2012). Our recordings would, however, miss most of the frequency range of beluga whale echolocation clicks (Au et al 1985).…”

“…Data from satellite tagging can provide good spatial and temporal coverage, but sample size can be very small (Hauser et al 2014;Citta et al 2015). Passive acoustic monitoring has been effectively used throughout the Arctic to study long-term trends in marine mammal distribution (Hannay et al 2013;Jones et al 2014;Clark et al 2015;Stafford et al 2018). We therefore used passive acoustic monitoring to examine patterns in marine mammal presence near Ulukhaktok, Northwest Territories, from October 2016 through April 2017.…”