title: Temporal segregation of the Australian and Antarctic blue whale call types (Balaenoptera musculusspp.).
abstract: We examined recordings from a 15-month (May 2009-July 2010) continuous acoustic data set collected from a bottom-mounted passive acoustic recorder at a sample frequency of 6kHz off Portland, Victoria, Australia (38°33'01″S, 141°15'13″E) off southern Australia. Analysis revealed that calls from both subspecies were recorded at this site, and general additive modeling revealed that the number of calls varied significantly across seasons. Antarctic blue whales were detected more frequently from July to October 2009 and June to July 2010, corresponding to the suspected breeding season, while Australian blue whales were recorded more frequently from March to June 2010, coinciding with the feeding season. In both subspecies, the number of calls varied with time of day; Antarctic blue whale calls were more prevalent in the night to early morning, while Australian blue whale calls were detected more often from midday to early evening. Using passive acoustic monitoring, we show that each subspecies adopts different seasonal and daily call patterns which may be related to the ecological strategies of these subspecies. This study demonstrates the importance of passive acoustics in enabling us to understand and monitor subtle differences in the behavior and ecology of cryptic sympatric marine mammals.
authors.affiliation: Evolution & Ecology Research Centre, School of BEES, University of New South Wales, Biological Sciences Building (D26), Randwick, Sydney, New South Wales 2052, Australia (JST, TA, NEB, TLR).
authors.forename: Joy S
authors.initials: JS
authors.lastname: Tripovich
authors.affiliation: Evolution & Ecology Research Centre, School of BEES, University of New South Wales, Biological Sciences Building (D26), Randwick, Sydney, New South Wales 2052, Australia (JST, TA, NEB, TLR).
authors.forename: Holger
authors.initials: H
authors.lastname: Klinck
authors.affiliation: Evolution & Ecology Research Centre, School of BEES, University of New South Wales, Biological Sciences Building (D26), Randwick, Sydney, New South Wales 2052, Australia (JST, TA, NEB, TLR).
authors.forename: Sharon L
authors.initials: SL
authors.lastname: Nieukirk
authors.affiliation: Evolution & Ecology Research Centre, School of BEES, University of New South Wales, Biological Sciences Building (D26), Randwick, Sydney, New South Wales 2052, Australia (JST, TA, NEB, TLR).
authors.forename: Tempe
authors.initials: T
authors.lastname: Adams
authors.affiliation: Evolution & Ecology Research Centre, School of BEES, University of New South Wales, Biological Sciences Building (D26), Randwick, Sydney, New South Wales 2052, Australia (JST, TA, NEB, TLR).
authors.forename: David K
authors.initials: DK
authors.lastname: Mellinger
authors.affiliation: Evolution & Ecology Research Centre, School of BEES, University of New South Wales, Biological Sciences Building (D26), Randwick, Sydney, New South Wales 2052, Australia (JST, TA, NEB, TLR).
authors.forename: Naysa E
authors.initials: NE
authors.lastname: Balcazar
authors.affiliation: Evolution & Ecology Research Centre, School of BEES, University of New South Wales, Biological Sciences Building (D26), Randwick, Sydney, New South Wales 2052, Australia (JST, TA, NEB, TLR).
authors.forename: Karolin
authors.initials: K
authors.lastname: Klinck
authors.affiliation: Evolution & Ecology Research Centre, School of BEES, University of New South Wales, Biological Sciences Building (D26), Randwick, Sydney, New South Wales 2052, Australia (JST, TA, NEB, TLR).
authors.forename: Evelyn J S
authors.initials: EJ
authors.lastname: Hall
authors.affiliation: Evolution & Ecology Research Centre, School of BEES, University of New South Wales, Biological Sciences Building (D26), Randwick, Sydney, New South Wales 2052, Australia (JST, TA, NEB, TLR).
authors.forename: Tracey L
authors.initials: TL
authors.lastname: Rogers
keywords: Australia; Balaenoptera musculus brevicauda; Balaenoptera musculus intermedia; calls; cryptic sympatric marine mammals; diel; ecology; seasonal; vocalizations