TY - JOUR

T1 - Spatial and temporal patterns of sound production in East Greenland narwhals

AU - Blackwell, Susanna B.

AU - Tervo, Outi M.

AU - Conrad, Alexander S.

AU - Sinding, Mikkel H. S.

AU - Hansen, Rikke G.

AU - Ditlevsen, Susanne

AU - Heide-jørgensen, Mads Peter

PY - 2018

Y1 - 2018

N2 - Changes in climate are rapidly modifying the Arctic environment. As a result, human activities Ðand the sounds they produceÐare predicted to increase in remote areas of Greenland, such as those inhabited by the narwhals (Monodon monoceros) of East Greenland. Meanwhile, nothing is known about these whales' acoustic behavior or their reactions to anthropogenic sounds. This lack of knowledge was addressed by instrumenting six narwhals in Scoresby Sound (Aug 2013±2016) with Acousonde™ acoustic tags and satellite tags. Continuous recordings over up to seven days were used to describe the acoustic behavior of the whales, in particular their use of three types of sounds serving two different purposes: echolocation clicks and buzzes, which serve feeding, and calls, presumably used for social communication. Logistic regression models were used to assess the effects of location in time and space on buzzing and calling rates. Buzzes were mostly produced at depths of 350±650 m and buzzing rates were higher in one particular fjord, likely a preferred feeding area. Calls generally occurred at shallower depths (<100 m), with more than half of these calls occurring near the surface (<7 m), where the whales also spent more than half of their time. A period of silence following release, present in all subjects, was attributed to the capture and tagging operations, emphasizing the importance of longer (multi-day) records. This study provides basic life-history information on a poorly known speciesÐand therefore control data in ongoing or future sound-effect studies.

AB - Changes in climate are rapidly modifying the Arctic environment. As a result, human activities Ðand the sounds they produceÐare predicted to increase in remote areas of Greenland, such as those inhabited by the narwhals (Monodon monoceros) of East Greenland. Meanwhile, nothing is known about these whales' acoustic behavior or their reactions to anthropogenic sounds. This lack of knowledge was addressed by instrumenting six narwhals in Scoresby Sound (Aug 2013±2016) with Acousonde™ acoustic tags and satellite tags. Continuous recordings over up to seven days were used to describe the acoustic behavior of the whales, in particular their use of three types of sounds serving two different purposes: echolocation clicks and buzzes, which serve feeding, and calls, presumably used for social communication. Logistic regression models were used to assess the effects of location in time and space on buzzing and calling rates. Buzzes were mostly produced at depths of 350±650 m and buzzing rates were higher in one particular fjord, likely a preferred feeding area. Calls generally occurred at shallower depths (<100 m), with more than half of these calls occurring near the surface (<7 m), where the whales also spent more than half of their time. A period of silence following release, present in all subjects, was attributed to the capture and tagging operations, emphasizing the importance of longer (multi-day) records. This study provides basic life-history information on a poorly known speciesÐand therefore control data in ongoing or future sound-effect studies.

U2 - 10.1371/journal.pone.0198295

DO - 10.1371/journal.pone.0198295

M3 - Journal article

C2 - 29897955

VL - 13

JO - PLoS ONE

JF - PLoS ONE

SN - 1932-6203

IS - 6

M1 - e0198295

ER -