Acoustic ecology of Antarctic pinnipeds

Abstract

In aquatic-mating pinnipeds, acoustic communication plays an important role in male competition and mate attraction. Vocal repertoire size and composition during the breeding season varies between species and is presumed to be a product of interspecific differences in sexual selection. In this study, we examine seasonal and diel patterns in acoustic repertoire size, composition and call activity of 4 Antarctic pinniped species: Weddell seal Leptonychotes weddellii, leopard seal Hydrurga leptonyx, Ross seal Ommatophoca rossii and crabeater seal Lobodon carcinophaga. An

Year-round acoustic detection of bearded seals (Erignathus barbatus) in the Beaufort Sea relative to changing environmental conditions, 2008–2010

“…The elevated bearded seal call activity in the early winter in the Beaufort Sea suggests that males are engaging in acoustic displays in their breeding territory for a large portion of the year and are, therefore, establishing and defending aquatic territories prior to spring. A similar yearround acoustic presence was observed in Weddell seals (Van Opzeeland et al 2010).…”

“…Smith et al 1997;Brenowitz 2004) and has been shown for other pinnipeds (captive Australian fur seals, Arctocephalus pusillus, Tripovich et al 2009; captive walrus, Odobenus rosmarus, Hughes et al 2011). As noted previously, in many species of pinniped, both land-and aquatic-mating, where males defend a territory or resource attractive to females, males establish these territories well before females give birth and then come into estrous (i.e., Le Boeuf and Peterson 1969;Van Parijs et al 1999;Kunc and Wolf 2008;Van Opzeeland et al 2010). The production, duration, and frequency range of trills produced by bearded seals are used by males to advertise quality to other males, and potentially females, as the breeding season progresses (Van Parijs et al 2001).…”

“…The distribution of vocalizing male bearded seals is dependent on available suitable haul out sites or ice conditions and by female distribution, which is determined by sea ice conditions and ecological requirements (Van Parijs et al 2001, 2004. Therefore, spatial variation in calling activity of males in the Beaufort Sea may be the result of more females congregating in areas of higher concentrations of prey and thereby influencing the distribution of vocalizing males (Van Parijs et al 2001;Van Opzeeland et al 2010).…”

“…Other studies have shown that some aquatic-mating pinnipeds produce calls year-round (Rouget et al 2007;Van Opzeeland et al 2010). The year-round occupancy of certain areas may give ''territorial'' males an advantage over the non-territorial or ''roaming'' males at the onset of mating season and simultaneous arrival of female seals to the area (Harcourt et al 2007;Harcourt et al 2008;Van Opzeeland et al 2010). The elevated bearded seal call activity in the early winter in the Beaufort Sea suggests that males are engaging in acoustic displays in their breeding territory for a large portion of the year and are, therefore, establishing and defending aquatic territories prior to spring.…”

“…There was a consistent presence of bearded seal calls in autumn at all locations from 2008 to 2010 with a slight peak occurring in late September/early October for both years. The autumn presence of bearded seals during the open water period suggests possible year-round residency of a small subpopulation of bearded seals in the Beaufort Sea or the early establishment of aquatic territories by ''territorial'' males (Van Parijs et al 2002;Van Opzeeland et al 2010).…”