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Michel M, Torterotot M, Royer JY, Samaran F. Effects of duty cycle on passive acoustic monitoring metrics: The case of blue whale songs. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2024; 155:2538-2548. [PMID: 38591939 DOI: 10.1121/10.0025545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 03/22/2024] [Indexed: 04/10/2024]
Abstract
Long-term fixed passive acoustic monitoring of cetacean populations is a logistical and technological challenge, often limited by the battery capacity of the autonomous recorders. Depending on the research scope and target species, temporal subsampling of the data may become necessary to extend the deployment period. This study explores the effects of different duty cycles on metrics that describe patterns of seasonal presence, call type richness richness, and daily call rate of three blue whale acoustics populations in the Southern Indian Ocean. Detections of blue whale calls from continuous acoustic data were subsampled with three different duty cycles of 50%, 33%, and 25% within listening periods ranging from 1 min to 6 h. Results show that reducing the percentage of recording time reduces the accuracy of the observed seasonal patterns as well as the estimation of daily call rate and call call type richness. For a specific duty cycle, short listening periods (5-30 min) are preferred to longer listening periods (1-6 h). The effects of subsampling are greater the lower the species' vocal activity or the shorter their periods of presence. These results emphasize the importance of selecting a subsampling scheme adapted to the target species.
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Affiliation(s)
- Mathilde Michel
- Centre National de la Recherche Scientifique Laboratoire des Sciences et Techniques de l'information, de la Communication et de la Connaissance, Ecole Nationale Supérieur de Techniques Avancées Bretagne, Brest, France
| | - Maëlle Torterotot
- Centre National de la Recherche Scientifique Laboratoire des Sciences et Techniques de l'information, de la Communication et de la Connaissance, Ecole Nationale Supérieur de Techniques Avancées Bretagne, Brest, France
| | - Jean-Yves Royer
- Lab Geo-Ocean, Centre National de la Recherche Scientifique, University of Brest, Ifremer, F-29280, Plouzané, France
| | - Flore Samaran
- Centre National de la Recherche Scientifique Laboratoire des Sciences et Techniques de l'information, de la Communication et de la Connaissance, Ecole Nationale Supérieur de Techniques Avancées Bretagne, Brest, France
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Ziegenhorn MA, Hildebrand JA, Oleson EM, Baird RW, Wiggins SM, Baumann‐Pickering S. Odontocete spatial patterns and temporal drivers of detection at sites in the Hawaiian islands. Ecol Evol 2023; 13:e9688. [PMID: 36620420 PMCID: PMC9817196 DOI: 10.1002/ece3.9688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 12/06/2022] [Accepted: 12/12/2022] [Indexed: 01/09/2023] Open
Abstract
Successful conservation and management of marine top predators rely on detailed documentation of spatiotemporal behavior. For cetacean species, this information is key to defining stocks, habitat use, and mitigating harmful interactions. Research focused on this goal is employing methodologies such as visual observations, tag data, and passive acoustic monitoring (PAM) data. However, many studies are temporally limited or focus on only one or few species. In this study, we make use of an existing long-term (2009-2019), labeled PAM data set to examine spatiotemporal patterning of at least 10 odontocete (toothed whale) species in the Hawaiian Islands using compositional analyses and modeling techniques. Species composition differs among considered sites, and this difference is robust to seasonal movement patterns. Temporally, hour of day was the most significant predictor of detection across species and sites, followed by season, though patterns differed among species. We describe long-term trends in species detection at one site and note that they are markedly similar for many species. These trends may be related to long-term, underlying oceanographic cycles that will be the focus of future study. We demonstrate the variability of temporal patterns even at relatively close sites, which may imply that wide-ranging models of species presence are missing key fine-scale movement patterns. Documented seasonal differences in detection also highlights the importance of considering season in survey design both regionally and elsewhere. We emphasize the utility of long-term, continuous monitoring in highlighting temporal patterns that may relate to underlying climatic states and help us predict responses to climate change. We conclude that long-term PAM records are a valuable resource for documenting spatiotemporal patterns and can contribute many insights into the lives of top predators, even in highly studied regions such as the Hawaiian Islands.
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Affiliation(s)
- Morgan A. Ziegenhorn
- Scripps Institution of OceanographyUniversity of California San DiegoLa JollaCaliforniaUSA
| | - John A. Hildebrand
- Scripps Institution of OceanographyUniversity of California San DiegoLa JollaCaliforniaUSA
| | - Erin M. Oleson
- NOAA Fisheries Pacific Islands Fisheries Science CenterHonoluluHawaiiUSA
| | | | - Sean M. Wiggins
- Scripps Institution of OceanographyUniversity of California San DiegoLa JollaCaliforniaUSA
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Ross-Marsh EC, Elwen SH, Fearey J, Thompson KF, Maack T, Gridley T. Detection of humpback whale (Megaptera novaeangliae) non-song vocalizations around the Vema Seamount, southeast Atlantic Ocean. JASA EXPRESS LETTERS 2022; 2:041201. [PMID: 36154232 DOI: 10.1121/10.0010072] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Humpback whales are a cosmopolitan, highly vocal species. Investigated here are their vocalizations recorded at the Vema Seamount (31°38'S, 08°20'E) from moored hydrophones in the austral spring of 2019. During the 11-d recording period over 600 non-song calls were detected. Calls were predominantly detected at night over three consecutive days. The most common calls were low, frequency-modulated sounds (whups). An impulsive sound (gunshot) previously unknown in humpback whales was also detected. The location and timing of the calls suggests that humpback whales may be using the Vema Seamount as a temporary stop on their migration to their polar feeding grounds.
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Affiliation(s)
- E C Ross-Marsh
- Department of Botany and Zoology, University of Stellenbosch, Stellenbosch, South Africa
| | - S H Elwen
- Department of Botany and Zoology, University of Stellenbosch, Stellenbosch, South Africa
| | - J Fearey
- Centre for Statistics in Ecology, Environment and Conservation, Department of Statistical Sciences, University of Cape Town, Western Cape, South Africa
| | - K F Thompson
- Biosciences, University of Exeter, Devon, United Kingdom
| | - T Maack
- Greenpeace Germany, Hongkongstrasse 10, 20457 Hamburg, Germany , , , , ,
| | - T Gridley
- Department of Botany and Zoology, University of Stellenbosch, Stellenbosch, South Africa
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Rand ZR, Wood JD, Oswald JN. Effects of duty cycles on passive acoustic monitoring of southern resident killer whale (Orcinus orca) occurrence and behavior. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2022; 151:1651. [PMID: 35364953 DOI: 10.1121/10.0009752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 02/13/2022] [Indexed: 06/14/2023]
Abstract
Long-term passive acoustic monitoring of cetaceans is frequently limited by the data storage capacity and battery life of the recording system. Duty cycles are a mechanism for subsampling during the recording process that facilitates long-term passive acoustic studies. While duty cycles are often used, there has been little investigation on the impact that this approach has on the ability to answer questions about a species' behavior and occurrence. In this study, the effects of duty cycling on the acoustic detection of southern resident killer whales (SRKW) (Orcinus orca) were investigated. Continuous acoustic data were subsampled to create 288 subsampled datasets with cycle lengths from 5 to 180 min and listening proportions from 1% to 67%. Duty cycles had little effect on the detection of the daily presence of SRKW, especially when using cycle lengths of less than an hour. However, cycle lengths of 15-30 min and listening proportions of at least 33% were required to accurately calculate durations of acoustic bouts and identify those bouts to ecotype. These results show that the optimal duty cycle depends on the scale of the research question and provide a framework for quantitative analysis of duty cycles for other marine species.
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Affiliation(s)
- Zoe R Rand
- Sea Mammal Research Unit, Scottish Oceans Institute, School of Biology, University of St Andrews, St Andrews, KY16 8LB, United Kingdom
| | - Jason D Wood
- SMRU Consulting, Friday Harbor, Washington 98250, USA
| | - Julie N Oswald
- Sea Mammal Research Unit, Scottish Oceans Institute, School of Biology, University of St Andrews, St Andrews, KY16 8LB, United Kingdom
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Stanistreet JE, Beslin WAM, Kowarski K, Martin SB, Westell A, Moors-Murphy HB. Changes in the acoustic activity of beaked whales and sperm whales recorded during a naval training exercise off eastern Canada. Sci Rep 2022; 12:1973. [PMID: 35132140 PMCID: PMC8821608 DOI: 10.1038/s41598-022-05930-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 01/20/2022] [Indexed: 11/09/2022] Open
Abstract
Experimental research has shown that beaked whales exhibit strong avoidance reactions to naval active sonars used during antisubmarine warfare training exercises, including cessation of echolocation and foraging activity. Behavioural responses to sonar have also been linked to strandings and mortality. Much of the research on the responses of beaked whales and other cetaceans to naval active sonar has occurred on or near U.S. naval training ranges, and the impacts of sonar in other regions remain poorly understood, particularly as these impacts, including mortality, are likely to go unobserved in offshore areas. In September 2016 the multinational naval exercise 'CUTLASS FURY 2016' (CF16) was conducted off eastern Canada. We used passive acoustic recordings collected in the region to quantify the occurrence and characteristics of sonar signals, measure ambient noise levels, and assess changes in the acoustic activity of beaked and sperm whales. The number of hours per day with echolocation clicks from Cuvier's beaked whales and sperm whales were significantly reduced during CF16, compared to the pre-exercise period in 2016 (sperm whales) and to control data from 2015 (both species). Clicks from an unidentified Mesoplodont beaked whale species, sporadically detected prior to CF16, were absent during the exercise and for 7 days afterward. These results suggest that beaked and sperm whales ceased foraging in the vicinity of CF16 and likely avoided the affected area. Such disturbance may have energetic, health, and fitness consequences.
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Affiliation(s)
- Joy E Stanistreet
- Fisheries and Oceans Canada, Bedford Institute of Oceanography, 1 Challenger Drive, Dartmouth, NS, Canada.
| | - Wilfried A M Beslin
- Fisheries and Oceans Canada, Bedford Institute of Oceanography, 1 Challenger Drive, Dartmouth, NS, Canada
| | - Katie Kowarski
- JASCO Applied Sciences, 32 Troop Avenue, Suite 202, Dartmouth, NS, Canada
| | - S Bruce Martin
- JASCO Applied Sciences, 32 Troop Avenue, Suite 202, Dartmouth, NS, Canada
| | - Annabel Westell
- Fisheries and Oceans Canada, Bedford Institute of Oceanography, 1 Challenger Drive, Dartmouth, NS, Canada
| | - Hilary B Moors-Murphy
- Fisheries and Oceans Canada, Bedford Institute of Oceanography, 1 Challenger Drive, Dartmouth, NS, Canada
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Simonis AE, Brownell RL, Thayre BJ, Trickey JS, Oleson EM, Huntington R, Baumann-Pickering S. Co-occurrence of beaked whale strandings and naval sonar in the Mariana Islands, Western Pacific. Proc Biol Sci 2020; 287:20200070. [PMID: 32070257 PMCID: PMC7062028 DOI: 10.1098/rspb.2020.0070] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Mid-frequency active sonar (MFAS), used for antisubmarine warfare (ASW), has been associated with multiple beaked whale (BW) mass stranding events. Multinational naval ASW exercises have used MFAS offshore of the Mariana Archipelago semi-annually since 2006. We report BW and MFAS acoustic activity near the islands of Saipan and Tinian from March 2010 to November 2014. Signals from Cuvier's (Ziphius cavirostris) and Blainville's beaked whales (Mesoplodon densirostris), and a third unidentified BW species, were detected throughout the recording period. Both recorders documented MFAS on 21 August 2011 before two Cuvier's beaked whales stranded on 22–23 August 2011. We compared the history of known naval operations and BW strandings from the Mariana Archipelago to consider potential threats to BW populations. Eight BW stranding events between June 2006 and January 2019 each included one to three animals. Half of these strandings occurred during or within 6 days after naval activities, and this co-occurrence is highly significant. We highlight strandings of individual BWs can be associated with ASW, and emphasize the value of ongoing passive acoustic monitoring, especially for beaked whales that are difficult to visually detect at sea. We strongly recommend more visual monitoring efforts, at sea and along coastlines, for stranded cetaceans before, during and after naval exercises.
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Affiliation(s)
- Anne E Simonis
- Contractor to Pacific Islands Fisheries Science Center, National Oceanic and Atmospheric Administration, Honolulu, HI, USA
| | - Robert L Brownell
- Southwest Fisheries Science Center, National Oceanic and Atmospheric Administration, Monterey, CA, USA
| | - Bruce J Thayre
- Scripps Institution of Oceanography, UCSD, La Jolla, CA, USA
| | | | - Erin M Oleson
- Pacific Islands Fisheries Science Center, National Oceanic and Atmospheric Administration, Honolulu, HI, USA
| | - Roderick Huntington
- Scripps Institution of Oceanography, UCSD, La Jolla, CA, USA.,Mount Edgecumbe High School, Sitka, AK, USA
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Shearer JM, Quick NJ, Cioffi WR, Baird RW, Webster DL, Foley HJ, Swaim ZT, Waples DM, Bell JT, Read AJ. Diving behaviour of Cuvier's beaked whales ( Ziphius cavirostris) off Cape Hatteras, North Carolina. ROYAL SOCIETY OPEN SCIENCE 2019; 6:181728. [PMID: 30891284 PMCID: PMC6408375 DOI: 10.1098/rsos.181728] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 01/09/2019] [Indexed: 05/07/2023]
Abstract
Cuvier's beaked whales exhibit exceptionally long and deep foraging dives. The species is little studied due to their deep-water, offshore distribution and limited time spent at the surface. We used LIMPET satellite tags to study the diving behaviour of Cuvier's beaked whales off Cape Hatteras, North Carolina from 2014 to 2016. We deployed 11 tags, recording 3242 h of behaviour data, encompassing 5926 dives. Dive types were highly bimodal; deep dives (greater than 800 m, n = 1408) had a median depth of 1456 m and median duration of 58.9 min; shallow dives (50-800 m, n = 4518) were to median depths of 280 m with a median duration of 18.7 min. Most surface intervals were very short (median 2.2 min), but all animals occasionally performed extended surface intervals. We found no diel differences in dive depth or the percentage of time spent deep diving, but whales spent significantly more time near the surface at night. Other populations of this species exhibit similar dive patterns, but with regional differences in depth, duration and inter-dive intervals. Satellite-linked tags allow for the collection of long periods of dive records, including the occurrence of anomalous behaviours, bringing new insights into the lives of these deep divers.
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Affiliation(s)
- Jeanne M. Shearer
- Duke Marine Lab, University Program in Ecology, 135 Duke Marine Lab Rd, Beaufort, NC 28516, USA
| | - Nicola J. Quick
- Duke University Marine Lab, 135 Duke Marine Lab Rd, Beaufort, NC 28516, USA
| | - William R. Cioffi
- Duke Marine Lab, University Program in Ecology, 135 Duke Marine Lab Rd, Beaufort, NC 28516, USA
| | - Robin W. Baird
- Cascadia Research Collective, 218 ½ W 4th Ave, Olympia, WA 98501, USA
| | - Daniel L. Webster
- Cascadia Research Collective, 218 ½ W 4th Ave, Olympia, WA 98501, USA
| | - Heather J. Foley
- Duke University Marine Lab, 135 Duke Marine Lab Rd, Beaufort, NC 28516, USA
| | - Zachary T. Swaim
- Duke University Marine Lab, 135 Duke Marine Lab Rd, Beaufort, NC 28516, USA
| | - Danielle M. Waples
- Duke University Marine Lab, 135 Duke Marine Lab Rd, Beaufort, NC 28516, USA
| | - Joel T. Bell
- Environmental Conservation – Marine Resources Section (EV53), Naval Facilities Engineering Command Atlantic, Norfolk, VA 23508, USA
| | - Andrew J. Read
- Duke University Marine Lab, 135 Duke Marine Lab Rd, Beaufort, NC 28516, USA
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