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Koschinski S, Owen K, Lehnert K, Kamińska K. Current species protection does not serve its porpoise-Knowledge gaps on the impact of pressures on the Critically Endangered Baltic Proper harbour porpoise population, and future recommendations for its protection. Ecol Evol 2024; 14:e70156. [PMID: 39267689 PMCID: PMC11392595 DOI: 10.1002/ece3.70156] [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: 01/02/2024] [Revised: 06/13/2024] [Accepted: 07/29/2024] [Indexed: 09/15/2024] Open
Abstract
Successful management requires information on pressures that threaten a species and areas where conservation actions are needed. The Baltic Proper harbour porpoise population was first listed as Critically Endangered by the International Union for the Conservation of Nature in 2008. Now, 16 years later, there is no change in conservation status despite ample conservation policy calling for its protection and an urgent need for management action to protect this population. Here, we provide an overview of the current status of the population, highlight knowledge gaps on the impact of pressures, and make recommendations for management of anthropogenic activities. Based on an exceeded limit for anthropogenic mortality, the high concentrations of contaminants in the Baltic Sea, combined with reductions in prey availability and increases in underwater noise, it is inferred that this population is likely still decreasing in size and conservation action becomes more urgent. As bycatch and unprotected underwater explosions result in direct mortality, they must be reduced to zero. Inputs of contaminants, waste, and existing and emerging noise sources should be minimised and regulated. Additionally, ecosystem-based sustainable management of fisheries is paramount in order to ensure prey availability, and maintain a healthy Baltic Sea. Stranding networks to routinely assess individuals for genetic population assignment and health need to be expanded, to identify rare samples from this population. Knowledge is still scarce on the population-level impact of each threat, along with the cumulative impact of multiple pressures on the population. However, the current knowledge and management instruments are sufficient to apply effective protection for the population now. While bycatch is the main pressure impacting this population, urgent conservation action is needed across all anthropogenic activities. Extinction of the Baltic Proper harbour porpoise population is a choice: decision-makers have the fate of this genetically and biologically distinct marine mammal population in their hands.
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Affiliation(s)
| | - Kylie Owen
- Department of Population Analysis and Monitoring Swedish Museum of Natural History Stockholm Sweden
| | - Kristina Lehnert
- Institute for Terrestrial and Aquatic Wildlife Research University of Veterinary Medicine Hannover Hannover Germany
| | - Katarzyna Kamińska
- Department of Fisheries Ministry of Agriculture and Rural Development Warsaw Poland
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Owen K, Carlström J, Eriksson P, Andersson M, Nordström R, Lalander E, Sveegaard S, Kyhn LA, Griffiths ET, Cosentino M, Tougaard J. Rerouting of a major shipping lane through important harbour porpoise habitat caused no detectable change in annual occurrence or foraging patterns. MARINE POLLUTION BULLETIN 2024; 202:116294. [PMID: 38537499 DOI: 10.1016/j.marpolbul.2024.116294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Revised: 03/21/2024] [Accepted: 03/22/2024] [Indexed: 05/08/2024]
Abstract
Shipping is one of the largest industries globally, with well-known negative impacts on the marine environment. Despite the known negative short-term (minutes to hours) impact of shipping on individual animal behavioural responses, very little is understood about the long-term (months to years) impact on marine species presence and area use. This study took advantage of a planned rerouting of a major shipping lane leading into the Baltic Sea, to investigate the impact on the presence and foraging behaviour of a marine species known to be sensitive to underwater noise, the harbour porpoise (Phocoena phocoena). Passive acoustic monitoring data were collected from 15 stations over two years. Against predictions, no clear change occurred in monthly presence or foraging behaviour of the porpoises, despite the observed changes in noise and vessel traffic. However, long-term heightened noise levels may still impact communication, echolocation, or stress levels of individuals, and needs further investigation.
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Affiliation(s)
- Kylie Owen
- Department of Population Analysis and Monitoring, Swedish Museum of Natural History, Frescativägen 40, Stockholm 104 05, Sweden.
| | - Julia Carlström
- Department of Population Analysis and Monitoring, Swedish Museum of Natural History, Frescativägen 40, Stockholm 104 05, Sweden
| | - Pia Eriksson
- Department of Population Analysis and Monitoring, Swedish Museum of Natural History, Frescativägen 40, Stockholm 104 05, Sweden
| | - Mathias Andersson
- Department of Defence Technology, FOI-Swedish Defence Research Agency, Stockholm, Sweden
| | - Robin Nordström
- Department of Defence Technology, FOI-Swedish Defence Research Agency, Stockholm, Sweden
| | - Emilia Lalander
- Department of Defence Technology, FOI-Swedish Defence Research Agency, Stockholm, Sweden
| | - Signe Sveegaard
- Section for Marine Mammal Research, Department of Ecoscience, Aarhus University, DK-4000 Roskilde, Denmark
| | - Line A Kyhn
- Section for Marine Mammal Research, Department of Ecoscience, Aarhus University, DK-4000 Roskilde, Denmark
| | - Emily T Griffiths
- Section for Marine Mammal Research, Department of Ecoscience, Aarhus University, DK-4000 Roskilde, Denmark
| | - Mel Cosentino
- Section for Marine Mammal Research, Department of Ecoscience, Aarhus University, DK-4000 Roskilde, Denmark
| | - Jakob Tougaard
- Section for Marine Mammal Research, Department of Ecoscience, Aarhus University, DK-4000 Roskilde, Denmark
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3
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Marques CS, Marques DA, Blackwell SB, Heide-Jørgensen MP, Malinka CE, Marques TA. Narwhal (Monodon monoceros) echolocation click rates to support cue counting passive acoustic density estimation. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2024; 155:891-900. [PMID: 38310606 DOI: 10.1121/10.0024723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 01/17/2024] [Indexed: 02/06/2024]
Abstract
Estimating animal abundance is fundamental for effective management and conservation. It is increasingly done by combining passive acoustics with knowledge about rates at which animals produce cues (cue rates). Narwhals (Monodon monoceros) are elusive marine mammals for which passive acoustic density estimation might be plausible, but for which cue rates are lacking. Clicking rates in narwhals were investigated using a dataset from sound and movement tag records collected in August 2013-2016 and 2019 in East Greenland. Clicking rates were quantified for ∼1200 one-second-long systematic random samples from 8 different whales. Generalized additive models were used to model (1) the probability of being in a clicking state versus depth and (2) the clicking rate while in a clicking state, versus time and depth. The probability of being in a clicking state increased with depth, reaching ∼1.0 at ∼500 m, while the number of clicks per second (while in a clicking state) increased with depth. The mean cue production rate, weighted by tag duration, was 1.28 clicks per second (se = 0.13, CV = 0.10). This first cue rate for narwhals may be used for cue counting density estimation, but care should be taken if applying it to other geographical areas or seasons, given sample size, geographical, and temporal limitations.
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Affiliation(s)
- Carolina S Marques
- Centro de Estatística e Aplicações, Departamento de Biologia Animal, Faculdade de Ciências da Universidade de Lisboa, Lisbon, Portugal
| | - Diana A Marques
- Centro de Estatística e Aplicações, Departamento de Biologia Animal, Faculdade de Ciências da Universidade de Lisboa, Lisbon, Portugal
| | - Susanna B Blackwell
- Greeneridge Sciences, Incorporated, 5142 Hollister Avenue, 283, Santa Barbara, California 93111, USA
| | | | - Chloe E Malinka
- Sea Mammal Research Unit Consulting, Scottish Oceans Institute, University of St Andrews, St Andrews, United Kingdom
| | - Tiago A Marques
- Centro de Estatística e Aplicações, Departamento de Biologia Animal, Faculdade de Ciências da Universidade de Lisboa, Lisbon, Portugal
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Macaulay JDJ, Rojano-Doñate L, Ladegaard M, Tougaard J, Teilmann J, Marques TA, Siebert U, Madsen PT. Implications of porpoise echolocation and dive behaviour on passive acoustic monitoring. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2023; 154:1982-1995. [PMID: 37782119 DOI: 10.1121/10.0021163] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 09/06/2023] [Indexed: 10/03/2023]
Abstract
Harbour porpoises are visually inconspicuous but highly soniferous echolocating marine predators that are regularly studied using passive acoustic monitoring (PAM). PAM can provide quality data on animal abundance, human impact, habitat use, and behaviour. The probability of detecting porpoise clicks within a given area (P̂) is a key metric when interpreting PAM data. Estimates of P̂ can be used to determine the number of clicks per porpoise encounter that may have been missed on a PAM device, which, in turn, allows for the calculation of abundance and ideally non-biased comparison of acoustic data between habitats and time periods. However, P̂ is influenced by several factors, including the behaviour of the vocalising animal. Here, the common implicit assumption that changes in animal behaviour have a negligible effect on P̂ between different monitoring stations or across time is tested. Using a simulation-based approach informed by acoustic biologging data from 22 tagged harbour porpoises, it is demonstrated that porpoise behavioural states can have significant (up to 3× difference) effects on P̂. Consequently, the behavioural state of the animals must be considered in analysis of animal abundance to avoid substantial over- or underestimation of the true abundance, habitat use, or effects of human disturbance.
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Affiliation(s)
- Jamie Donald John Macaulay
- Department of Biology-Zoophysiology, Aarhus University, C. F. Møllers Allé 3, building 1131, 8000 Aarhus C, Denmark
| | - Laia Rojano-Doñate
- Department of Biology-Zoophysiology, Aarhus University, C. F. Møllers Allé 3, building 1131, 8000 Aarhus C, Denmark
| | - Michael Ladegaard
- Department of Biology-Zoophysiology, Aarhus University, C. F. Møllers Allé 3, building 1131, 8000 Aarhus C, Denmark
| | - Jakob Tougaard
- Department of Ecoscience-Marine Mammal Research, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark
| | - Jonas Teilmann
- Department of Ecoscience-Marine Mammal Research, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark
| | - Tiago A Marques
- Centre for Research into Ecological and Environmental Modelling, University of St. Andrews, St. Andrews, Scotland, United Kingdom
| | - Ursula Siebert
- Department of Ecoscience-Marine Mammal Research, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark
| | - Peter Teglberg Madsen
- Department of Biology-Zoophysiology, Aarhus University, C. F. Møllers Allé 3, building 1131, 8000 Aarhus C, Denmark
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Patris J, Malige F, Hamame M, Glotin H, Barchasz V, Gies V, Marzetti S, Buchan S. Medium-term acoustic monitoring of small cetaceans in Patagonia, Chile. PeerJ 2023; 11:e15292. [PMID: 37334123 PMCID: PMC10276556 DOI: 10.7717/peerj.15292] [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: 01/06/2022] [Accepted: 04/04/2023] [Indexed: 06/20/2023] Open
Abstract
Coastal dolphins and porpoises such as the Chilean dolphin (Cephalorhynchus eutropia), the Peale's dolphin (Lagenorhynchus australis), and the Burmeister's porpoise (Phocoena spinipinnis) inhabit the remote areas of Chilean Patagonia. Human development is growing fast in these parts and may constitute a serious threat to such poorly known species. It is thus urgent to develop new tools to try and study these cryptic species and find out more about their behavior, population levels, and habits. These odontocetes emit narrow-band high-frequency (NBHF) clicks and efforts have been made to characterize precisely their acoustic production. Passive acoustic monitoring is a common way to study these animals. Nevertheless, as the signal frequency is usually higher than 100 kHz, storage problems are acute and do not allow for long-term monitoring. The solutions for recording NBHF clicks are usually twofold: either short duration, opportunistic recording from a small boat in presence of the animals (short-term monitoring) or long-term monitoring using devices including a click detector and registering events rather than sound. We suggest, as another possibility, medium-term monitoring, arguing that today's devices have reached a level of performance allowing for a few days of continual recording even at these extremely high frequencies and in difficult conditions, combined with a long-term click detector. As an example, during 2021, we performed a quasi-continuous recording for one week with the Qualilife High-Blue recorder anchored in a fjord near Puerto Cisnes, Region de Aysen, Chile. We detected more than 13,000 clicks, grouped in 22 periods of passing animals. Our detected clicks are quite similar to precedent results but, due to the large number of clicks recorded, we find a larger variability of parameters. Several rapid sequences of clicks (buzz) were found in the recordings and their features are consistent with previous studies: on average they have a larger bandwidth and a lower peak frequency than the usual clicks. We also installed in the same place a click detector (C-POD) and the two devices compare well and show the same number and duration of periods of animals presence. Passages of odontocetes were happening on average each three hours. We thus confirm the high site fidelity for the species of dolphins emitting NBHF clicks present in this zone. Finally, we confirm that the combined use of recording and detection devices is probably a good alternative to study these poorly known species in remote areas.
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Affiliation(s)
| | - Franck Malige
- Laboratoire Informatique et Systèmes (LIS), CNRS UMR 7020, Toulon, France
| | - Madeleine Hamame
- Centro de Investigación en Ecosistemas de la Patagonia (CIEP), Coyhaique, Chile
| | - Hervé Glotin
- Laboratoire Informatique et Systèmes (LIS), CNRS UMR 7020, Toulon, France
- Scientific Microsystems for Internet of Things (SMIoT), Université de Toulon et du Var, Toulon, France
| | - Valentin Barchasz
- Scientific Microsystems for Internet of Things (SMIoT), Université de Toulon et du Var, Toulon, France
| | - Valentin Gies
- Scientific Microsystems for Internet of Things (SMIoT), Université de Toulon et du Var, Toulon, France
- Institut Matériaux Microélectronique Nanosciences de Provence (IM2NP), CNRS UMR 7334, Toulon, France
| | - Sebastian Marzetti
- Scientific Microsystems for Internet of Things (SMIoT), Université de Toulon et du Var, Toulon, France
- Institut Matériaux Microélectronique Nanosciences de Provence (IM2NP), CNRS UMR 7334, Toulon, France
| | - Susannah Buchan
- Center for Oceanographic Research COPAS COASTAL, Universidad de Concepción, Concepción, Chile
- Departamento de Oceanografía, Universidad de Concepción, Concepción, Chile
- Centro de Estudios Avanzado en Zonas Aridas (CEAZA), Coquimbo, Chile
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Beedholm K, Ladegaard M, Madsen PT, Tyack PL. Latencies of click-evoked auditory responses in a harbor porpoise exceed the time interval between subsequent echolocation clicks. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2023; 153:952. [PMID: 36859123 DOI: 10.1121/10.0017163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 01/17/2023] [Indexed: 06/18/2023]
Abstract
Most auditory evoked potential (AEP) studies in echolocating toothed whales measure neural responses to outgoing clicks and returning echoes using short-latency auditory brainstem responses (ABRs) arising a few ms after acoustic stimuli. However, little is known about longer-latency cortical AEPs despite their relevance for understanding echo processing and auditory stream segregation. Here, we used a non-invasive AEP setup with low click repetition rates on a trained harbor porpoise to test the long-standing hypothesis that echo information from distant targets is completely processed before the next click is emitted. We reject this hypothesis by finding reliable click-related AEP peaks with latencies of 90 and 160 ms, which are longer than 99% of click intervals used by echolocating porpoises, demonstrating that some higher-order echo processing continues well after the next click emission even during slow clicking. We propose that some of the echo information, such as range to evasive prey, is used to guide vocal-motor responses within 50-100 ms, but that information used for discrimination and auditory scene analysis is processed more slowly, integrating information over many click-echo pairs. We conclude by showing theoretically that the identified long-latency AEPs may enable hearing sensitivity measurements at frequencies ten times lower than current ABR methods.
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Affiliation(s)
- K Beedholm
- Zoophysiology, Department of Biology, Aarhus University, Aarhus C 8000, Denmark
| | - M Ladegaard
- Zoophysiology, Department of Biology, Aarhus University, Aarhus C 8000, Denmark
| | - P T Madsen
- Zoophysiology, Department of Biology, Aarhus University, Aarhus C 8000, Denmark
| | - P L Tyack
- School of Biology, University of St Andrews, St Andrews KY16 9ST, Scotland
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Macaulay J, Kingston A, Coram A, Oswald M, Swift R, Gillespie D, Northridge S. Passive acoustic tracking of the three‐dimensional movements and acoustic behaviour of toothed whales in close proximity to static nets. Methods Ecol Evol 2022. [DOI: 10.1111/2041-210x.13828] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jamie Macaulay
- Sea Mammal Research Unit Scottish Oceans Institute Scotland, UK
| | - Al Kingston
- Sea Mammal Research Unit Scottish Oceans Institute Scotland, UK
| | - Alex Coram
- Sea Mammal Research Unit Scottish Oceans Institute Scotland, UK
| | - Michael Oswald
- Sea Mammal Research Unit Scottish Oceans Institute Scotland, UK
| | - René Swift
- Sea Mammal Research Unit Scottish Oceans Institute Scotland, UK
| | - Doug Gillespie
- Sea Mammal Research Unit Scottish Oceans Institute Scotland, UK
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Amundin M, Carlström J, Thomas L, Carlén I, Teilmann J, Tougaard J, Loisa O, Kyhn LA, Sveegaard S, Burt ML, Pawliczka I, Koza R, Arciszewski B, Galatius A, Laaksonlaita J, MacAuley J, Wright AJ, Gallus A, Dähne M, Acevedo‐Gutiérrez A, Benke H, Koblitz J, Tregenza N, Wennerberg D, Brundiers K, Kosecka M, Tiberi Ljungqvist C, Jussi I, Jabbusch M, Lyytinen S, Šaškov A, Blankett P. Estimating the abundance of the critically endangered Baltic Proper harbour porpoise ( Phocoena phocoena) population using passive acoustic monitoring. Ecol Evol 2022; 12:e8554. [PMID: 35222950 PMCID: PMC8858216 DOI: 10.1002/ece3.8554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Revised: 12/17/2021] [Accepted: 12/20/2021] [Indexed: 11/18/2022] Open
Abstract
Knowing the abundance of a population is a crucial component to assess its conservation status and develop effective conservation plans. For most cetaceans, abundance estimation is difficult given their cryptic and mobile nature, especially when the population is small and has a transnational distribution. In the Baltic Sea, the number of harbour porpoises (Phocoena phocoena) has collapsed since the mid-20th century and the Baltic Proper harbour porpoise is listed as Critically Endangered by the IUCN and HELCOM; however, its abundance remains unknown. Here, one of the largest ever passive acoustic monitoring studies was carried out by eight Baltic Sea nations to estimate the abundance of the Baltic Proper harbour porpoise for the first time. By logging porpoise echolocation signals at 298 stations during May 2011-April 2013, calibrating the loggers' spatial detection performance at sea, and measuring the click rate of tagged individuals, we estimated an abundance of 71-1105 individuals (95% CI, point estimate 491) during May-October within the population's proposed management border. The small abundance estimate strongly supports that the Baltic Proper harbour porpoise is facing an extremely high risk of extinction, and highlights the need for immediate and efficient conservation actions through international cooperation. It also provides a starting point in monitoring the trend of the population abundance to evaluate the effectiveness of management measures and determine its interactions with the larger neighboring Belt Sea population. Further, we offer evidence that design-based passive acoustic monitoring can generate reliable estimates of the abundance of rare and cryptic animal populations across large spatial scales.
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Affiliation(s)
| | - Julia Carlström
- AquaBiota Water ResearchStockholmSweden
- Present address:
Department of Environmental Research and MonitoringSwedish Museum of Natural HistoryStockholmSweden
| | - Len Thomas
- Centre for Research into Ecological and Environmental ModellingUniversity of St AndrewsSt AndrewsUK
| | - Ida Carlén
- AquaBiota Water ResearchStockholmSweden
- Present address:
Department of ZoologyStockholm UniversityStockholmSweden
| | - Jonas Teilmann
- Marine Mammal ResearchDepartment of BioscienceAarhus UniversityRoskildeDenmark
| | - Jakob Tougaard
- Marine Mammal ResearchDepartment of BioscienceAarhus UniversityRoskildeDenmark
| | - Olli Loisa
- Turku University of Applied SciencesTurkuFinland
| | - Line A. Kyhn
- Marine Mammal ResearchDepartment of BioscienceAarhus UniversityRoskildeDenmark
| | - Signe Sveegaard
- Marine Mammal ResearchDepartment of BioscienceAarhus UniversityRoskildeDenmark
| | - M. Louise Burt
- Centre for Research into Ecological and Environmental ModellingUniversity of St AndrewsSt AndrewsUK
| | - Iwona Pawliczka
- Prof. Krzysztof Skóra Hel Marine StationDepartment of Oceanography and GeographyUniversity of GdańskHelPoland
| | - Radomil Koza
- Prof. Krzysztof Skóra Hel Marine StationDepartment of Oceanography and GeographyUniversity of GdańskHelPoland
| | - Bartlomiej Arciszewski
- Prof. Krzysztof Skóra Hel Marine StationDepartment of Oceanography and GeographyUniversity of GdańskHelPoland
| | - Anders Galatius
- Marine Mammal ResearchDepartment of BioscienceAarhus UniversityRoskildeDenmark
| | | | - Jamie MacAuley
- School of BiologyBute BuildingUniversity of St AndrewsSt AndrewsUK
- Present address:
Department of Biology ‐ ZoophysiologyAarhus UniversityAarhusDenmark
| | - Andrew J. Wright
- Marine Mammal ResearchDepartment of BioscienceAarhus UniversityRoskildeDenmark
- Present address:
Fisheries and Oceans CanadaMaritimes, DartmouthNova ScotiaCanada
| | | | | | | | | | - Jens Koblitz
- German Oceanographic MuseumStralsundGermany
- Present address:
Max Planck Institute of Animal BehaviorKonstanzGermany
- Present address:
Centre for the Advanced Study of Collective BehaviourUniversity of KonstanzKonstanzGermany
- Present address:
Department of BiologyUniversity of KonstanzKonstanzGermany
| | | | - Daniel Wennerberg
- Kolmarden Wildlife ParkKolmårdenSweden
- Present address:
Swedish Meteorological and Hydrological Institute, Core ServicesNorrköpingSweden
| | | | - Monika Kosecka
- Prof. Krzysztof Skóra Hel Marine StationDepartment of Oceanography and GeographyUniversity of GdańskHelPoland
- Present address:
Scottish Association for Marine ScienceUniversity of Highlands and IslandsObanUK
| | - Cinthia Tiberi Ljungqvist
- Kolmarden Wildlife ParkKolmårdenSweden
- Present address:
County Administrative Board of StockholmStockholmSweden
| | - Ivar Jussi
- ProMare NPOVintriku Saula küla, Kose valdHarjumaaEstonia
| | | | | | - Aleksej Šaškov
- Marine Research instituteKlaipėda UniversityKlaipėdaLithuania
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9
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Zahn MJ, Laidre KL, Stilz P, Rasmussen MH, Koblitz JC. Vertical sonar beam width and scanning behavior of wild belugas (Delphinapterus leucas) in West Greenland. PLoS One 2021; 16:e0257054. [PMID: 34499678 PMCID: PMC8428689 DOI: 10.1371/journal.pone.0257054] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 08/22/2021] [Indexed: 11/18/2022] Open
Abstract
Echolocation signals of wild beluga whales (Delphinapterus leucas) were recorded in 2013 using a vertical, linear 16-hydrophone array at two locations in the pack ice of Baffin Bay, West Greenland. Individual whales were localized for 4:42 minutes of 1:04 hours of recordings. Clicks centered on the recording equipment (i.e. on-axis clicks) were isolated to calculate sonar parameters. We report the first sonar beam estimate of in situ recordings of wild belugas with an average -3 dB asymmetrical vertical beam width of 5.4°, showing a wider ventral beam. This narrow beam width is consistent with estimates from captive belugas; however, our results indicate that beluga sonar beams may not be symmetrical and may differ in wild and captive contexts. The mean apparent source level for on-axis clicks was 212 dB pp re 1 μPa and whales were shown to vertically scan the array from 120 meters distance. Our findings support the hypothesis that highly directional sonar beams and high source levels are an evolutionary adaptation for Arctic odontocetes to reduce unwanted surface echoes from sea ice (i.e., acoustic clutter) and effectively navigate through leads in the pack ice (e.g., find breathing holes). These results provide the first baseline beluga sonar metrics from free-ranging animals using a hydrophone array and are important for acoustic programs throughout the Arctic, particularly for acoustic classification between belugas and narwhals (Monodon monoceros).
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Affiliation(s)
- Marie J Zahn
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA, United States of America
| | - Kristin L Laidre
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA, United States of America.,Polar Science Center, Applied Physics Laboratory, University of Washington, Seattle, WA, United States of America
| | - Peter Stilz
- Animal Physiology, Institute for Neurobiology, University of Tübingen, Tübingen, Germany
| | | | - Jens C Koblitz
- Max Planck Institute of Animal Behavior, Konstanz, Germany.,Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Konstanz, Germany.,Department of Biology, University of Konstanz, Konstanz, Germany
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10
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Malinka CE, Rojano-Doñate L, Madsen PT. Directional biosonar beams allow echolocating harbour porpoises to actively discriminate and intercept closely spaced targets. J Exp Biol 2021; 224:271830. [PMID: 34387665 DOI: 10.1242/jeb.242779] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 06/28/2021] [Indexed: 10/20/2022]
Abstract
Echolocating toothed whales face the problem that high sound speeds in water mean that echoes from closely spaced targets will arrive at time delays within their reported auditory integration time of some 264 µs. Here, we test the hypothesis that echolocating harbour porpoises cannot resolve and discriminate targets within a clutter interference zone given by their integration time. To do this, we trained two harbour porpoises (Phocoena phocoena) to actively approach and choose between two spherical targets at four varying inter-target distances (13.5, 27, 56 and 108 cm) in a two-alternative forced-choice task. The free-swimming, blindfolded porpoises were tagged with a sound and movement tag (DTAG4) to record their echoic scene and acoustic outputs. The known ranges between targets and the porpoise, combined with the sound levels received on target-mounted hydrophones revealed how the porpoises controlled their acoustic gaze. When targets were close together, the discrimination task was more difficult because of smaller echo time delays and lower echo level ratios between the targets. Under these conditions, buzzes were longer and started from farther away, source levels were reduced at short ranges, and the porpoises clicked faster, scanned across the targets more, and delayed making their discrimination decision until closer to the target. We conclude that harbour porpoises can resolve and discriminate closely spaced targets, suggesting a clutter rejection zone much shorter than their auditory integration time, and that such clutter rejection is greatly aided by spatial filtering with their directional biosonar beam.
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Affiliation(s)
- Chloe E Malinka
- Zoophysiology, Department of Biology, Aarhus University, Aarhus 8000, Denmark
| | - Laia Rojano-Doñate
- Zoophysiology, Department of Biology, Aarhus University, Aarhus 8000, Denmark
| | - Peter T Madsen
- Zoophysiology, Department of Biology, Aarhus University, Aarhus 8000, Denmark
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Owen K, Sköld M, Carlström J. An increase in detection rates of the critically endangered Baltic Proper harbor porpoise in Swedish waters in recent years. CONSERVATION SCIENCE AND PRACTICE 2021. [DOI: 10.1111/csp2.468] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Affiliation(s)
- Kylie Owen
- Department of Environmental Research and Monitoring Swedish Museum of Natural History Stockholm Sweden
| | - Martin Sköld
- Department of Environmental Research and Monitoring Swedish Museum of Natural History Stockholm Sweden
- Department of Mathematics Stockholm University Stockholm Sweden
| | - Julia Carlström
- Department of Environmental Research and Monitoring Swedish Museum of Natural History Stockholm Sweden
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Malinka CE, Tønnesen P, Dunn CA, Claridge DE, Gridley T, Elwen SH, Teglberg Madsen P. Echolocation click parameters and biosonar behaviour of the dwarf sperm whale ( Kogia sima). J Exp Biol 2021; 224:224/6/jeb240689. [PMID: 33771935 DOI: 10.1242/jeb.240689] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 02/11/2021] [Indexed: 11/20/2022]
Abstract
Dwarf sperm whales (Kogia sima) are small toothed whales that produce narrow-band high-frequency (NBHF) echolocation clicks. Such NBHF clicks, subject to high levels of acoustic absorption, are usually produced by small, shallow-diving odontocetes, such as porpoises, in keeping with their short-range echolocation and fast click rates. Here, we sought to address the problem of how the little-studied and deep-diving Kogia can hunt with NBHF clicks in the deep sea. Specifically, we tested the hypotheses that Kogia produce NBHF clicks with longer inter-click intervals (ICIs), higher directionality and higher source levels (SLs) compared with other NBHF species. We did this by deploying an autonomous deep-water vertical hydrophone array in the Bahamas, where no other NBHF species are present, and by taking opportunistic recordings of a close-range Kogia sima in a South African harbour. Parameters from on-axis clicks (n=46) in the deep revealed very narrow-band clicks (root mean squared bandwidth, BWRMS, of 3±1 kHz), with SLs of up to 197 dB re. 1 µPa peak-to-peak (μPapp) at 1 m, and a half-power beamwidth of 8.8 deg. Their ICIs (mode of 245 ms) were much longer than those of porpoises (<100 ms), suggesting an inspection range that is longer than detection ranges of single prey, perhaps to facilitate auditory streaming of a complex echo scene. On-axis clicks in the shallow harbour (n=870) had ICIs and SLs in keeping with source parameters of other NBHF cetaceans. Thus, in the deep, dwarf sperm whales use a directional, but short-range echolocation system with moderate SLs, suggesting a reliable mesopelagic prey habitat.
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Affiliation(s)
- Chloe E Malinka
- Zoophysiology, Department of Biology, Aarhus University, 8000 Aarhus, Denmark
| | - Pernille Tønnesen
- Zoophysiology, Department of Biology, Aarhus University, 8000 Aarhus, Denmark
| | - Charlotte A Dunn
- Bahamas Marine Mammal Research Organisation (BMMRO), Sandy Point, Abaco, Bahamas.,Sea Mammal Research Unit, University of St Andrews, St Andrews KY16 8LB, UK
| | - Diane E Claridge
- Bahamas Marine Mammal Research Organisation (BMMRO), Sandy Point, Abaco, Bahamas.,Sea Mammal Research Unit, University of St Andrews, St Andrews KY16 8LB, UK
| | - Tess Gridley
- Department of Botany and Zoology, Stellenbosch University, Stellenbosch 7605, South Africa.,Sea Search Research and Conservation, Muizenberg, Cape Town 7945, South Africa
| | - Simon H Elwen
- Department of Botany and Zoology, Stellenbosch University, Stellenbosch 7605, South Africa.,Sea Search Research and Conservation, Muizenberg, Cape Town 7945, South Africa
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Pellegrini AY, Romeu B, Ingram SN, Daura‐Jorge FG. Boat disturbance affects the acoustic behaviour of dolphins engaged in a rare foraging cooperation with fishers. Anim Conserv 2021. [DOI: 10.1111/acv.12667] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- A. Y. Pellegrini
- Programa de Pós‐graduação em Ecologia Departamento de Ecologia e Zoologia Universidade Federal de Santa Catarina. Campus Universitário Florianópolis SC Brazil
| | - B. Romeu
- Programa de Pós‐graduação em Ecologia Departamento de Ecologia e Zoologia Universidade Federal de Santa Catarina. Campus Universitário Florianópolis SC Brazil
| | - S. N. Ingram
- School of Biological and Marine Sciences University of Plymouth Plymouth United Kingdom
| | - F. G. Daura‐Jorge
- Programa de Pós‐graduação em Ecologia Departamento de Ecologia e Zoologia Universidade Federal de Santa Catarina. Campus Universitário Florianópolis SC Brazil
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