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Ryan C, Martins MCI, Healy K, Bejder L, Cerchio S, Christiansen F, Durban J, Fearnbach H, Fortune S, Friedlaender A, Koski WR, Miller C, Rodríguez-González FM, Segre PS, Urbán R J, Vivier F, Weir CR, Moore MJ. Morphology of nares associated with stereo-olfaction in baleen whales. Biol Lett 2024; 20:20230479. [PMID: 38290551 PMCID: PMC10827433 DOI: 10.1098/rsbl.2023.0479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 01/04/2024] [Indexed: 02/01/2024] Open
Abstract
The sensory mechanisms used by baleen whales (Mysticeti) for locating ephemeral, dense prey patches in vast marine habitats are poorly understood. Baleen whales have a functional olfactory system with paired rather than single blowholes (nares), potentially enabling stereo-olfaction. Dimethyl sulfide (DMS) is an odorous gas emitted by phytoplankton in response to grazing by zooplankton. Some seabirds use DMS to locate prey, but this ability has not been demonstrated in whales. For 14 extant species of baleen whale, nares morphometrics (imagery from unoccupied aerial systems, UAS) was related to published trophic level indices using Bayesian phylogenetic mixed modelling. A significant negative relationship was found between nares width and whale trophic level (β = -0.08, lower 95% CI = -0.13, upper 95% CI = -0.03), corresponding with a 39% increase in nares width from highest to lowest trophic level. Thus, species with nasal morphology best suited to stereo-olfaction are more zooplanktivorous. These findings provide evidence that some baleen whale species may be able to localize odorants e.g. DMS. Our results help direct future behavioural trials of olfaction in baleen whales, by highlighting the most appropriate species to study. This is a research priority, given the potential for DMS-mediated plastic ingestion by whales.
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Affiliation(s)
- Conor Ryan
- Scottish Association for Marine Science, Argyll PA37 1QA, UK
| | - Maria C. I. Martins
- Sea Mammal Research Unit, Scottish Oceans Institute, School of Biology, University of St Andrews, East Sands KY16 8LB, UK
| | - Kevin Healy
- Zoology Department, School of Natural Sciences, National University of Ireland Galway, Galway H91 TK33, Ireland
| | - Lars Bejder
- Marine Mammal Research Program, Hawai'i Institute of Marine Biology, University of Hawai‘i at Mānoa, Kāne'ohe, Hawai'i, USA
| | - Salvatore Cerchio
- African Aquatic Conservation Fund, P.O. Box 366, Chilmark, MA 02535, USA
| | - Fredrik Christiansen
- Marine Mammal Research, Department of Ecoscience, Aarhus University, 4000 Roskilde, Denmark
| | - John Durban
- SR3, SeaLife Response, Rehabilitation and Research, Des Moines, WA, USA
| | - Holly Fearnbach
- SR3, SeaLife Response, Rehabilitation and Research, Des Moines, WA, USA
| | - Sarah Fortune
- Department of Oceanography, Dalhousie University, Halifax, NS, Canada
| | - Ari Friedlaender
- Institute of Marine Sciences, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - William R. Koski
- LGL Limited Environmental Research Associates, 22 Fisher Street, King City, Ontario, Canada, L7B 1A6
| | - Carolyn Miller
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | | | - Paolo S. Segre
- Department of Natural and Applied Sciences, University of Wisconsin, Green Bay, WI, USA
- Hopkins Marine Station, Oceans Department, Stanford University, Stanford, CA, USA
| | - Jorge Urbán R
- Departamento de Ciencias Marinas y Costeras, Universidad Autónoma de Baja California Sur, La Paz, BCS, México
| | - Fabien Vivier
- Marine Mammal Research Program, Hawai'i Institute of Marine Biology, University of Hawai‘i at Mānoa, Kāne'ohe, Hawai'i, USA
| | - Caroline R. Weir
- Falklands Conservation, Jubilee Villas, 41 Ross Road, Stanley, Falkland Islands
| | - Michael J. Moore
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
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Vivier F, Wells RS, Hill MC, Yano KM, Bradford AL, Leunissen EM, Pacini A, Booth CG, Rocho‐Levine J, Currie JJ, Patton PT, Bejder L. Quantifying the age structure of free-ranging delphinid populations: Testing the accuracy of Unoccupied Aerial System photogrammetry. Ecol Evol 2023; 13:e10082. [PMID: 37384246 PMCID: PMC10293808 DOI: 10.1002/ece3.10082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Revised: 04/13/2023] [Accepted: 04/25/2023] [Indexed: 06/30/2023] Open
Abstract
Understanding the population health status of long-lived and slow-reproducing species is critical for their management. However, it can take decades with traditional monitoring techniques to detect population-level changes in demographic parameters. Early detection of the effects of environmental and anthropogenic stressors on vital rates would aid in forecasting changes in population dynamics and therefore inform management efforts. Changes in vital rates strongly correlate with deviations in population growth, highlighting the need for novel approaches that can provide early warning signs of population decline (e.g., changes in age structure). We tested a novel and frequentist approach, using Unoccupied Aerial System (UAS) photogrammetry, to assess the population age structure of small delphinids. First, we measured the precision and accuracy of UAS photogrammetry in estimating total body length (TL) of trained bottlenose dolphins (Tursiops truncatus). Using a log-transformed linear model, we estimated TL using the blowhole to dorsal fin distance (BHDF) for surfacing animals. To test the performance of UAS photogrammetry to age-classify individuals, we then used length measurements from a 35-year dataset from a free-ranging bottlenose dolphin community to simulate UAS estimates of BHDF and TL. We tested five age classifiers and determined where young individuals (<10 years) were assigned when misclassified. Finally, we tested whether UAS-simulated BHDF only or the associated TL estimates provided better classifications. TL of surfacing dolphins was overestimated by 3.3% ±3.1% based on UAS-estimated BHDF. Our age classifiers performed best in predicting age-class when using broader and fewer (two and three) age-class bins with ~80% and ~72% assignment performance, respectively. Overall, 72.5%-93% of the individuals were correctly classified within 2 years of their actual age-class bin. Similar classification performances were obtained using both proxies. UAS photogrammetry is a non-invasive, inexpensive, and effective method to estimate TL and age-class of free-swimming dolphins. UAS photogrammetry can facilitate the detection of early signs of population changes, which can provide important insights for timely management decisions.
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Affiliation(s)
- Fabien Vivier
- Marine Mammal Research ProgramHawaiʻi Institute of Marine BiologyUniversity of Hawaiʻi at MānoaMānoaHawaiʻiUSA
| | - Randall S. Wells
- Chicago Zoological Society's Sarasota Dolphin Research Programc/o Mote Marine LaboratorySarasotaFloridaUSA
| | - Marie C. Hill
- Cooperative Institute for Marine and Atmospheric ResearchResearch Corporation of the University of HawaiʻiHonoluluHawaiʻiUSA
- Pacific Islands Fisheries Science CenterNOAA FisheriesHonoluluHawaiʻiUSA
| | - Kymberly M. Yano
- Cooperative Institute for Marine and Atmospheric ResearchResearch Corporation of the University of HawaiʻiHonoluluHawaiʻiUSA
- Pacific Islands Fisheries Science CenterNOAA FisheriesHonoluluHawaiʻiUSA
| | - Amanda L. Bradford
- Pacific Islands Fisheries Science CenterNOAA FisheriesHonoluluHawaiʻiUSA
| | - Eva M. Leunissen
- Department of Marine ScienceUniversity of OtagoDunedinNew Zealand
| | - Aude Pacini
- Marine Mammal Research ProgramHawaiʻi Institute of Marine BiologyUniversity of Hawaiʻi at MānoaMānoaHawaiʻiUSA
| | - Cormac G. Booth
- SMRU ConsultingScottish Oceans InstituteUniversity of St AndrewsSt AndrewsUK
| | | | - Jens J. Currie
- Marine Mammal Research ProgramHawaiʻi Institute of Marine BiologyUniversity of Hawaiʻi at MānoaMānoaHawaiʻiUSA
- Pacific Whale FoundationWailukuHawaiʻiUSA
| | - Philip T. Patton
- Marine Mammal Research ProgramHawaiʻi Institute of Marine BiologyUniversity of Hawaiʻi at MānoaMānoaHawaiʻiUSA
| | - Lars Bejder
- Marine Mammal Research ProgramHawaiʻi Institute of Marine BiologyUniversity of Hawaiʻi at MānoaMānoaHawaiʻiUSA
- ZoophysiologyDepartment of BioscienceAarhus UniversityAarhusDenmark
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Currie JJ, van Aswegen M, Stack SH, West KL, Vivier F, Bejder L. Rapid weight loss in free ranging pygmy killer whales (Feresa attenuata) and the implications for anthropogenic disturbance of odontocetes. Sci Rep 2021; 11:8181. [PMID: 33854117 PMCID: PMC8046785 DOI: 10.1038/s41598-021-87514-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 03/30/2021] [Indexed: 11/09/2022] Open
Abstract
Understanding the impacts of foraging disruptions to odontocete body condition is fundamental to quantifying biological effects of human disturbance and environmental changes on cetacean populations. Here, reductions in body volume of free-ranging pygmy killer whales (Feresa attenuata) were calculated using repeated measurements of the same individuals obtained through Unoccupied Aerial System (UAS)-photogrammetry during a prolonged disruption in foraging activity arising from a 21-day stranding event. Stranded individuals were used to verify UAS-derived volume and length estimates through 3D-imaging, water displacement, and post-mortem measurements. We show that (a) UAS estimates of length were within 1.5% of actual body length and UAS volume estimates were within 10-13% of actual volume, (b) foraging disruption resulted in a daily decrease of 2% of total body mass/day, and (c) pygmy killer whales can lose up to 27% of their total body weight within 17 days. These findings highlight the use of UAS as a promising new method to remotely monitor changes in body condition and animal health, which can be used to determine the potential effects of anthropogenic disturbance and environmental change on free-ranging odontocetes.
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Affiliation(s)
| | - Martin van Aswegen
- Marine Mammal Research Program, Hawaii Institute of Marine Biology, University of Hawaii at Manoa, Kaneohe, HI, USA
| | | | - Kristi L West
- Hawaii Institute of Marine Biology, Kaneohe, HI, USA
- Human Nutrition Food and Animal Sciences, College of Tropical Agriculture and Human Resources, Honolulu, HI, USA
| | - Fabien Vivier
- Marine Mammal Research Program, Hawaii Institute of Marine Biology, University of Hawaii at Manoa, Kaneohe, HI, USA
| | - Lars Bejder
- Marine Mammal Research Program, Hawaii Institute of Marine Biology, University of Hawaii at Manoa, Kaneohe, HI, USA
- Zoophysiology, Department of Biology, Aarhus University, Aarhus, Denmark
- Centre for Sustainable Aquatic Ecosystems, Harry Butler Institute, Murdoch University, Murdoch, WA, Australia
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