title: Seasonal migrations of North Atlantic minke whales: novel insights from large-scale passive acoustic monitoring networks.
abstract: BACKGROUND
  Little is known about migration patterns and seasonal distribution away from coastal summer feeding habitats of many pelagic baleen whales. Recently, large-scale passive acoustic monitoring networks have become available to explore migration patterns and identify critical habitats of these species. North Atlantic minke whales (Balaenoptera acutorostrata) perform seasonal migrations between high latitude summer feeding and low latitude winter breeding grounds. While the distribution and abundance of the species has been studied across their summer range, data on migration and winter habitat are virtually missing. Acoustic recordings, from 16 different sites from across the North Atlantic, were analyzed to examine the seasonal and geographic variation in minke whale pulse train occurrence, infer information about migration routes and timing, and to identify possible winter habitats.
  
  
  RESULTS
  Acoustic detections show that minke whales leave their winter grounds south of 30° N from March through early April. On their southward migration in autumn, minke whales leave waters north of 40° N from mid-October through early November. In the western North Atlantic spring migrants appear to track the warmer waters of the Gulf Stream along the continental shelf, while whales travel farther offshore in autumn. Abundant detections were found off the southeastern US and the Caribbean during winter. Minke whale pulse trains showed evidence of geographic variation, with longer pulse trains recorded south of 40° N. Very few pulse trains were recorded during summer in any of the datasets.
  
  
  CONCLUSIONS
  This study highlights the feasibility of using acoustic monitoring networks to explore migration patterns of pelagic marine mammals. Results confirm the presence of minke whales off the southeastern US and the Caribbean during winter months. The absence of pulse train detections during summer suggests either that minke whales switch their vocal behaviour at this time of year, are absent from available recording sites or that variation in signal structure influenced automated detection. Alternatively, if pulse trains are produced in a reproductive context by males, these data may indicate their absence from the selected recording sites. Evidence of geographic variation in pulse train duration suggests different behavioural functions or use of these calls at different latitudes.
authors.affiliation: Under Contract with Northeast Fisheries Science Center, National Marine Fisheries Service, NOAA, Woods Hole, MA USA ; Scottish Association for Marine Science (SAMS), Scottish Marine Institute, Oban, Argyll, Scotland UK.
authors.forename: Denise
authors.initials: D
authors.lastname: Risch
authors.affiliation: National Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, NOAA, Seattle, WA USA.
authors.forename: Manuel
authors.initials: M
authors.lastname: Castellote
authors.affiliation: Bioacoustics Research Program, Laboratory of Ornithology, Cornell University, Ithaca, NY USA.
authors.forename: Christopher W
authors.initials: CW
authors.lastname: Clark
authors.affiliation: Under Contract with Northeast Fisheries Science Center, National Marine Fisheries Service, NOAA, Woods Hole, MA USA.
authors.forename: Genevieve E
authors.initials: GE
authors.lastname: Davis
authors.affiliation: Bioacoustics Research Program, Laboratory of Ornithology, Cornell University, Ithaca, NY USA.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Dugan
authors.affiliation: Duke University Marine Laboratory, Beaufort, NC USA.
authors.forename: Lynne Ew
authors.initials: LE
authors.lastname: Hodge
authors.affiliation: Naval Facilities Engineering Command Atlantic, Norfolk, VA USA.
authors.forename: Anurag
authors.initials: A
authors.lastname: Kumar
authors.affiliation: IMARES Wageningen UR, Ecosystem Department, Den Burg, Texel The Netherlands ; Centre for Marine Science & Technology, Curtin University, Perth, WA Australia.
authors.forename: Klaus
authors.initials: K
authors.lastname: Lucke
authors.affiliation: NOAA Pacific Marine Environmental Laboratory, Newport, OR USA ; Cooperative Institute for Marine Resources Studies, Oregon State University, Newport, OR USA.
authors.forename: David K
authors.initials: DK
authors.lastname: Mellinger
authors.affiliation: NOAA Pacific Marine Environmental Laboratory, Newport, OR USA.
authors.forename: Sharon L
authors.initials: SL
authors.lastname: Nieukirk
authors.affiliation: Bioacoustics Research Program, Laboratory of Ornithology, Cornell University, Ithaca, NY USA.
authors.forename: Cristian Marian
authors.initials: CM
authors.lastname: Popescu
authors.affiliation: Mingan Island Cetacean Study, Longue-Pointe-de-Mingan, QC Canada.
authors.forename: Christian
authors.initials: C
authors.lastname: Ramp
authors.affiliation: Duke University Marine Laboratory, Beaufort, NC USA.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Read
authors.affiliation: Bioacoustics Research Program, Laboratory of Ornithology, Cornell University, Ithaca, NY USA.
authors.forename: Aaron N
authors.initials: AN
authors.lastname: Rice
authors.affiliation: MARE-Marine and Environmental Sciences Centre and IMAR-Institute of Marine Research, University of the Azores, Horta, Portugal ; Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA USA.
authors.forename: Monica A
authors.initials: MA
authors.lastname: Silva
authors.affiliation: Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Büsum Germany.
authors.forename: Ursula
authors.initials: U
authors.lastname: Siebert
authors.affiliation: Applied Physics Laboratory, University of Washington, Seattle, WA USA.
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: Stafford
authors.affiliation: IMARES Wageningen UR, Ecosystem Department, Den Burg, Texel The Netherlands.
authors.forename: Hans
authors.initials: H
authors.lastname: Verdaat
authors.affiliation: Northeast Fisheries Science Center, National Marine Fisheries Service, NOAA, Woods Hole, MA USA.
authors.forename: Sofie M
authors.initials: SM
authors.lastname: Van Parijs
keywords: Balaenoptera acutorostrata; Geographic variation; Migration; Minke whales; Passive acoustic monitoring (PAM); Pulse trains; Seasonality