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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: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [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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Kok ACM, Hildebrand MJ, MacArdle M, Martinez A, Garrison LP, Soldevilla MS, Hildebrand JA. Kinematics and energetics of foraging behavior in Rice's whales of the Gulf of Mexico. Sci Rep 2023; 13:8996. [PMID: 37268677 DOI: 10.1038/s41598-023-35049-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 05/11/2023] [Indexed: 06/04/2023] Open
Abstract
Rorqual foraging behavior varies with species, prey type and foraging conditions, and can be a determining factor for their fitness. Little is known about the foraging ecology of Rice's whales (Balaenoptera ricei), an endangered species with a population of fewer than 100 individuals. Suction cup tags were attached to two Rice's whales to collect information on their diving kinematics and foraging behavior. The tagged whales primarily exhibited lunge-feeding near the sea bottom and to a lesser extent in the water-column and at the sea surface. During 6-10 min foraging dives, the whales typically circled their prey before executing one or two feeding lunges. Longer duration dives and dives with more feeding-lunges were followed by an increase in their breathing rate. The median lunge rate of one lunge per dive of both animals was much lower than expected based on comparative research on other lunge-feeding baleen whales, and may be associated with foraging on fish instead of krill or may be an indication of different foraging conditions. Both animals spent extended periods of the night near the sea surface, increasing the risk for ship strike. Furthermore, their circling before lunging may increase the risk for entanglement in bottom-longline fishing gear. Overall, these data show that Rice's whale foraging behavior differs from other lunge feeding rorqual species and may be a significant factor in shaping our understanding of their foraging ecology. Efforts to mitigate threats to Rice's whales will benefit from improved understanding of patterns in their habitat use and fine-scale ecology.
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Affiliation(s)
- Annebelle C M Kok
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, 92093, USA.
| | - Maya J Hildebrand
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, 92093, USA
| | - Maria MacArdle
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, 92093, USA
| | - Anthony Martinez
- Marine Mammal and Turtle Division, Southeast Fisheries Science Center, National Marine Fisheries Service, Miami, FL, USA
| | - Lance P Garrison
- Marine Mammal and Turtle Division, Southeast Fisheries Science Center, National Marine Fisheries Service, Miami, FL, USA
| | - Melissa S Soldevilla
- Marine Mammal and Turtle Division, Southeast Fisheries Science Center, National Marine Fisheries Service, Miami, FL, USA
| | - John A Hildebrand
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, 92093, USA
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