Underwater acoustic behavior of bearded seals (Erignathus barbatus) in the northeastern Chukchi Sea, 2007-2010
Bearded seal (Erignathus barbatus) calls were recorded using autonomous passive acoustic recorders deployed in the northeastern Chukchi Sea between October 2007 and October 2010. Continuous acoustic data were acquired during summer (August to mid‐October), and overwinter data (mid‐October through Ju...
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Published in | Marine mammal science Vol. 32; no. 1; pp. 141 - 160 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
Beaufort
Blackwell Publishing Ltd
01.01.2016
Wiley Subscription Services, Inc |
Subjects | |
Online Access | Get full text |
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Summary: | Bearded seal (Erignathus barbatus) calls were recorded using autonomous passive acoustic recorders deployed in the northeastern Chukchi Sea between October 2007 and October 2010. Continuous acoustic data were acquired during summer (August to mid‐October), and overwinter data (mid‐October through July) were acquired on a duty cycle of 40/48 min every 4 h. We investigated the spatio‐temporal distribution and acoustic behavior of vocalizing bearded seals in this multiyear data set. Peaks in calling occurred in spring, coinciding with the mating period, and calls stopped abruptly in late June/early July. Fewer calls were detected in summer, and the vocal presence of seals increased with the formation of pack ice in winter. Vocal activity was higher at night than during the day, with a peak around 0400 (AKST). Monthly patterns in proportional use of each call type and call duration were examined for the first time. The proportion and duration of AL1(T) and AL2(T) call types increased during the mating period, suggesting that males advertise their breeding condition by producing those specific longer trills. The observed seasonal and diel trends were consistent between years. These results improve our understanding of occurrence and acoustic behavior of bearded seals across the northeastern Chukchi Sea. |
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Bibliography: | ArticleID:MMS12246 istex:00128CCF82F9321A2356C27022AF427C294B9F98 Statoil USA E&P, Inc ark:/67375/WNG-0LBX9Q64-P Table S1. Call types for bearded seals annotated during manual analysis of the overwinter 2007-2008, 2008-2009, and 2009-2010 data sets. Call types are modified from Risch et al. (). Abbreviations: AL = Alaska, T = trill, M = moan, A = ascent. See Figure for example spectrograms of each call type. Table S2. Bearded seal vocal repertoire descriptive statistics for 2007-2010 recordings (overwinter data sets, one 20 min file every third day; n = 115,739), 2008-2009 recordings from 120 km north-northwest of Barrow, Alaska (Jones et al. ; n = 1,228) and 1985-2001 recordings from Point Barrow (Risch et al., ; n = 2,291). Table S3. Parametric coefficient results and AIC values of the Gaussian distribution Generalized Additive Models (GAM) of the effect of sea-ice coverage, month, station, latitude, longitude, ice edge distance, depth, and distance to shore on the call counts. Table S4. Results of 2-way ANOVA for monthly and annual effects on bearded seal call type occurrence. Asterisks indicate significant effects (P < 0.05). Figure S1. Columns are the percentage of roaming (A) and territorial (B) male bearded seals at each station during three overwinter recordings (white: 2007-2008; grey: 2008-2009; black: 2009-2010) using Van Parijs and Clark () classification (roaming males made AL1i(T) longer than 11.9 s, while territorial males had AL1i(T) less than 11.9 s long). Error bars are the mean duration (in seconds) ± SE. ConocoPhillips Company Shell Exploration & Production Company ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0824-0469 1748-7692 |
DOI: | 10.1111/mms.12246 |