title: Influence of environmental parameters on movements and habitat utilization of humpback whales (Megaptera novaeangliae) in the Madagascar breeding ground.
abstract: Assessing the movement patterns and key habitat features of breeding humpback whales is a prerequisite for the conservation management of this philopatric species. To investigate the interactions between humpback whale movements and environmental conditions off Madagascar, we deployed 25 satellite tags in the northeast and southwest coast of Madagascar. For each recorded position, we collated estimates of environmental variables and computed two behavioural metrics: behavioural state of 'transiting' (consistent/directional) versus 'localized' (variable/non-directional), and active swimming speed (i.e. speed relative to the current). On coastal habitats (i.e. bathymetry < 200 m and in adjacent areas), females showed localized behaviour in deep waters (191 ± 20 m) and at large distances (14 ± 0.6 km) from shore, suggesting that their breeding habitat extends beyond the shallowest waters available close to the coastline. Males' active swimming speed decreased in shallow waters, but environmental parameters did not influence their likelihood to exhibit localized movements, which was probably dominated by social factors instead. In oceanic habitats, both males and females showed localized behaviours in shallow waters and favoured high chlorophyll-aconcentrations. Active swimming speed accounts for a large proportion of observed movement speed; however, breeding humpback whales probably exploit prevailing ocean currents to maximize displacement. This study provides evidence that coastal areas, generally subject to strong human pressure, remain the core habitat of humpback whales off Madagascar. Our results expand the knowledge of humpback whale habitat use in oceanic habitat and response to variability of environmental factors such as oceanic current and chlorophyll level.
authors.affiliation: Bioacoustics Team, Institut de Neurosciences Paris-Saclay (NeuroPSI), CNRS UMR 8195, Université Paris Sud, 91405 Orsay, France; Sorbonne Universités (UPMC, Univ. Paris 06)-CNRS-IRD-MNHN, LOCEAN-IPSL, 4 place Jussieu, 75005 Paris, France; Biotope, Unité Recherche et Développement, 22 Boulevard Maréchal Foch, BP 58, 34140 Meze, France.
authors.forename: Laurène
authors.identifier: 0000-0002-3608-7916
authors.initials: L
authors.lastname: Trudelle
authors.affiliation: New England Aquarium, Central Wharf, Boston, MA, USA; Woods Hole Oceanographic Institution, 266 Woods Hole Road, Woods Hole, MA 02543, USA.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Cerchio
authors.affiliation: National Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, NOAA, 7600 Sand Point Way NE, Seattle, WA 98125, USA; Cascadia Research Collective, 218 1/2 4th Avenue W, Olympia, WA 98501, USA; Instituto Aqualie, Av. Dr. Paulo Japiassú 714/206, Juiz de Fora, MG 36033-310, Brazil.
authors.forename: Alexandre N
authors.initials: AN
authors.lastname: Zerbini
authors.affiliation: Instituto Aqualie , Av. Dr. Paulo Japiassú 714/206, Juiz de Fora, MG 36033-310 , Brazil.
authors.forename: Ygor
authors.initials: Y
authors.lastname: Geyer
authors.affiliation: Cetamada, Port Barachois , Ambodifotatra BP 5, 515 Sainte Marie , Madagascar.
authors.forename: François-Xavier
authors.initials: FX
authors.lastname: Mayer
authors.affiliation: BioGemme Laboratory , Brest , France.
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Jung
authors.affiliation: Institute of Plant Sciences-'Biotic interactions' group, Altenbergrain 21, 3013 Bern, Switzerland; INRA, UMR1349 IGEPP, 35653 Le Rheu, France.
authors.forename: Maxime R
authors.initials: MR
authors.lastname: Hervé
authors.affiliation: Sorbonne Universités (UPMC, Univ. Paris 06)-CNRS-IRD-MNHN, LOCEAN-IPSL, 4 place Jussieu, 75005 Paris, France; Department of Oceanography, University of Cape Town, Cape Town, South Africa.
authors.forename: Stephane
authors.initials: S
authors.lastname: Pous
authors.affiliation: Sorbonne Universités (UPMC, Univ. Paris 06)-CNRS-IRD-MNHN , LOCEAN-IPSL, 4 place Jussieu, 75005 Paris , France.
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Sallée
authors.affiliation: Ocean Giants Program , Wildlife Conservation Society , 2300 Southern Blvd, Bronx, NY 10460 , USA.
authors.forename: Howard C
authors.initials: HC
authors.lastname: Rosenbaum
authors.affiliation: Bioacoustics Team, Institut de Neurosciences Paris-Saclay (NeuroPSI), CNRS UMR 8195, Université Paris Sud, 91405 Orsay, France; Sorbonne Université, UPMC Univ Paris 06, CNRS UMR 7190, Institut Jean Le Rond d'Alembert, 75005 Paris, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Adam
authors.affiliation: Sorbonne Universités (UPMC, Univ. Paris 06)-CNRS-IRD-MNHN , LOCEAN-IPSL, 4 place Jussieu, 75005 Paris , France.
authors.forename: Jean-Benoit
authors.initials: JB
authors.lastname: Charrassin
keywords: Madagascar; environmental parameters; habitat use; humpback whales; movement patterns; satellite telemetry