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Angelakis N, Goldsworthy SD, Connell SD, Durante LM. A novel method for identifying fine-scale bottom-use in a benthic-foraging pinniped. MOVEMENT ECOLOGY 2023; 11:34. [PMID: 37296462 PMCID: PMC10257308 DOI: 10.1186/s40462-023-00386-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 04/16/2023] [Indexed: 06/12/2023]
Abstract
BACKGROUND For diving, marine predators, accelerometer and magnetometer data provides critical information on sub-surface foraging behaviours that cannot be identified from location or time-depth data. By measuring head movement and body orientation, accelerometers and magnetometers can help identify broad shifts in foraging movements, fine-scale habitat use and energy expenditure of terrestrial and marine species. Here, we use accelerometer and magnetometer data from tagged Australian sea lions and provide a new method to identify key benthic foraging areas. As Australian sea lions are listed as endangered by the IUCN and Australian legislation, identifying key areas for the species is vital to support targeted management of populations. METHODS Firstly, tri-axial magnetometer and accelerometer data from adult female Australian sea lions is used in conjunction with GPS and dive data to dead-reckon their three-dimensional foraging paths. We then isolate all benthic phases from their foraging trips and calculate a range of dive metrics to characterise their bottom usage. Finally, k-means cluster analysis is used to identify core benthic areas utilised by sea lions. Backwards stepwise regressions are then iteratively performed to identify the most parsimonious model for describing bottom usage and its included predictor variables. RESULTS Our results show distinct spatial partitioning in benthic habitat-use by Australian sea lions. This method has also identified individual differences in benthic habitat-use. Here, the application of high-resolution magnetometer/accelerometer data has helped reveal the tortuous foraging movements Australian sea lions use to exploit key benthic marine habitats and features. CONCLUSIONS This study has illustrated how magnetometer and accelerometer data can provide a fine-scale description of the underwater movement of diving species, beyond GPS and depth data alone, For endangered species like Australian sea lions, management of populations must be spatially targeted. Here, this method demonstrates a fine-scale analysis of benthic habitat-use which can help identify key areas for both marine and terrestrial species. Future integration of this method with concurrent habitat and prey data would further augment its power as a tool for understanding the foraging behaviours of species.
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Affiliation(s)
- Nathan Angelakis
- University of Adelaide, North Terrace, Adelaide, SA, 5000, Australia.
| | - Simon D Goldsworthy
- University of Adelaide, North Terrace, Adelaide, SA, 5000, Australia
- South Australian Research and Development Institute (SARDI) (Aquatic Sciences), 2 Hamra Avenue, West Beach, SA, 5024, Australia
| | - Sean D Connell
- University of Adelaide, North Terrace, Adelaide, SA, 5000, Australia
| | - Leonardo M Durante
- South Australian Research and Development Institute (SARDI) (Aquatic Sciences), 2 Hamra Avenue, West Beach, SA, 5024, Australia
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2
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Meyers N, Speakman CN, Dorville NASY, Hindell MA, Semmens JM, Monk J, Baylis AMM, Ierodiaconou D, Hoskins AJ, Marshall GJ, Abernathy K, Arnould JPY. The cost of a meal: factors influencing prey profitability in Australian fur seals. PeerJ 2021; 9:e12608. [PMID: 34966597 PMCID: PMC8667761 DOI: 10.7717/peerj.12608] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 11/17/2021] [Indexed: 12/02/2022] Open
Abstract
Knowledge of the factors shaping the foraging behaviour of species is central to understanding their ecosystem role and predicting their response to environmental variability. To maximise survival and reproduction, foraging strategies must balance the costs and benefits related to energy needed to pursue, manipulate, and consume prey with the nutritional reward obtained. While such information is vital for understanding how changes in prey assemblages may affect predators, determining these components is inherently difficult in cryptic predators. The present study used animal-borne video data loggers to investigate the costs and benefits related to different prey types for female Australian fur seals (Arctocephalus pusillus doriferus), a primarily benthic foraging species in the low productivity Bass Strait, south-eastern Australia. A total of 1,263 prey captures, resulting from 2,027 prey detections, were observed in 84.5 h of video recordings from 23 individuals. Substantial differences in prey pursuit and handling times, gross energy gain and total energy expenditure were observed between prey types. Importantly, the profitability of prey was not significantly different between prey types, with the exception of elasmobranchs. This study highlights the benefit of animal-borne video data loggers for understanding the factors that influence foraging decisions in predators. Further studies incorporating search times for different prey types would further elucidate how profitability differs with prey type.
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Affiliation(s)
- Nelle Meyers
- School of Life and Environmental Sciences, Deakin University, Burwood, Victoria, Australia.,Flanders Marine Institute (VLIZ), Ostend, Belgium.,Institute for Agricultural and Fisheries Research (ILVO), Ostend, Belgium
| | - Cassie N Speakman
- School of Life and Environmental Sciences, Deakin University, Burwood, Victoria, Australia
| | - Nicole A S-Y Dorville
- School of Life and Environmental Sciences, Deakin University, Burwood, Victoria, Australia.,Department of Biology, Centre for Forest Interdisciplinary Research, University of Winnipeg, Winnipeg, Manitoba, Canada
| | - Mark A Hindell
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania, Australia
| | - Jayson M Semmens
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania, Australia
| | - Jacquomo Monk
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania, Australia
| | - Alistair M M Baylis
- School of Life and Environmental Sciences, Deakin University, Burwood, Victoria, Australia.,South Atlantic Environmental Research Institute, Stanley, Falkland Islands
| | - Daniel Ierodiaconou
- School of Life and Environmental Sciences, Deakin University, Burwood, Victoria, Australia
| | - Andrew J Hoskins
- School of Life and Environmental Sciences, Deakin University, Burwood, Victoria, Australia.,CSIRO Health and Biosecurity, Townsville, Queensland, Australia
| | - Greg J Marshall
- Exploration Technology Lab, National Geographic Society, Washington D.C., United States of America
| | - Kyler Abernathy
- Exploration Technology Lab, National Geographic Society, Washington D.C., United States of America
| | - John P Y Arnould
- School of Life and Environmental Sciences, Deakin University, Burwood, Victoria, Australia
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3
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John JS, Thometz NM, Boerner K, Denum L, Kendall TL, Richter BP, Gaspard JC, Williams TM. Metabolic trade-offs in tropical and subtropical marine mammals: unique maintenance and locomotion costs in West Indian manatees and Hawaiian monk seals. J Exp Biol 2021; 224:jeb237628. [PMID: 34357378 PMCID: PMC8353161 DOI: 10.1242/jeb.237628] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 06/09/2021] [Indexed: 11/20/2022]
Abstract
Unlike the majority of marine mammal species, Hawaiian monk seals (Neomonachus schauinslandi) and West Indian manatees (Trichechus manatus latirostris) reside exclusively in tropical or subtropical waters. Although potentially providing an energetic benefit through reduced maintenance and thermal costs, little is known about the cascading effects that may alter energy expenditure during activity, dive responses and overall energy budgets for these warm-water species. To examine this, we used open-flow respirometry to measure the energy expended during resting and swimming in both species. We found that the average resting metabolic rates (RMRs) for both the adult monk seal (753.8±26.1 kJ h-1, mean±s.e.m.) and manatees (887.7±19.5 kJ h-1) were lower than predicted for cold-water marine mammal species of similar body mass. Despite these relatively low RMRs, both total cost per stroke and total cost of transport (COTTOT) during submerged swimming were similar to predictions for comparably sized marine mammals (adult monk seal: cost per stroke=5.0±0.2 J kg-1 stroke-1, COTTOT=1.7±0.1 J kg-1 m-1; manatees: cost per stroke=2.0±0.4 J kg-1 stroke-1, COTTOT=0.87±0.17 J kg-1 m-1). These lower maintenance costs result in less variability in adjustable metabolic costs that occur during submergence for warm-water species. However, these reduced maintenance costs do not appear to confer an advantage in overall energetic costs during activity, potentially limiting the capacity of warm-water species to respond to anthropogenic or environmental threats that require increased energy expenditure.
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Affiliation(s)
- Jason S. John
- University of California Santa Cruz, Coastal Biology Building, 130 McAllister Way, Santa Cruz, CA 95060, USA
| | - Nicole M. Thometz
- University of California Santa Cruz, Coastal Biology Building, 130 McAllister Way, Santa Cruz, CA 95060, USA
- University of San Francisco, 2130 Fulton Street, San Francisco, CA 94117, USA
| | - Katharine Boerner
- Mote Marine Laboratory & Aquarium, 1600 Ken Thompson Pkwy, Sarasota, FL 34236, USA
| | - Laura Denum
- Mote Marine Laboratory & Aquarium, 1600 Ken Thompson Pkwy, Sarasota, FL 34236, USA
| | - Traci L. Kendall
- University of California Santa Cruz, Coastal Biology Building, 130 McAllister Way, Santa Cruz, CA 95060, USA
| | - Beau P. Richter
- University of California Santa Cruz, Coastal Biology Building, 130 McAllister Way, Santa Cruz, CA 95060, USA
| | - Joseph C. Gaspard
- Pittsburgh Zoo & PPG Aquarium, One Wild Place, Pittsburgh, PA 15206, USA
| | - Terrie M. Williams
- University of California Santa Cruz, Coastal Biology Building, 130 McAllister Way, Santa Cruz, CA 95060, USA
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4
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Kim S, Jeong J, Seo SG, Im S, Lee WY, Jin SH. Remote Recognition of Moving Behaviors for Captive Harbor Seals Using a Smart-Patch System via Bluetooth Communication. MICROMACHINES 2021; 12:267. [PMID: 33806662 PMCID: PMC7999431 DOI: 10.3390/mi12030267] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 02/15/2021] [Accepted: 02/25/2021] [Indexed: 12/21/2022]
Abstract
Animal telemetry has been recognized as a core platform for exploring animal species due to future opportunities in terms of its contribution toward marine fisheries and living resources. Herein, biologging systems with pressure sensors are successfully implemented via open-source hardware platforms, followed by immediate application to captive harbor seals (HS). Remotely captured output voltage signals in real-time mode via Bluetooth communication were reproducibly and reliably recorded on the basis of hours using a smartphone built with data capturing software with graphic user interface (GUI). Output voltages, corresponding to typical behaviors on the captive HS, such as stopping (A), rolling (B), flapping (C), and sliding (D), are clearly obtained, and their analytical interpretation on captured electrical signals are fully validated via a comparison study with consecutively captured images for each motion of the HS. Thus, the biologging system with low cost and light weight, which is fully compatible with a conventional smartphone, is expected to potentially contribute toward future anthology of seal animals.
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Affiliation(s)
- Seungyeob Kim
- Department of Electronic Engineering, Incheon National University, Incheon 22012, Korea; (S.K.); (J.J.); (S.G.S.)
| | - Jinheon Jeong
- Department of Electronic Engineering, Incheon National University, Incheon 22012, Korea; (S.K.); (J.J.); (S.G.S.)
| | - Seung Gi Seo
- Department of Electronic Engineering, Incheon National University, Incheon 22012, Korea; (S.K.); (J.J.); (S.G.S.)
| | - Sehyeok Im
- Division of Polar Life Sciences, Korea Polar Research Institute, Incheon 21990, Korea;
| | - Won Young Lee
- Division of Polar Life Sciences, Korea Polar Research Institute, Incheon 21990, Korea;
| | - Sung Hun Jin
- Department of Electronic Engineering, Incheon National University, Incheon 22012, Korea; (S.K.); (J.J.); (S.G.S.)
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5
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Kienle SS, Powers J, Kendall T, Richter B, Castle L, Lentes G, Costa D, Mehta RS. Context Matters: Hawaiian Monk Seals Switch Between Feeding Strategies Depending on Ecological Context. Integr Comp Biol 2020; 60:425-439. [PMID: 32726403 DOI: 10.1093/icb/icaa075] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The ability to expand the behavioral repertoire past seemingly rigid morphological features enables animals to succeed in a variety of ecological contexts. The integration of morphology, performance, and behavior produces diverse animal feeding strategies. These different strategies reflect trade-offs between specialization, prey choice, and energetic expenditure, which have important consequences for understanding individual and population-level flexibility in response to environmental change. Here we examined the feeding strategies used by the Hawaiian monk seal (Neomonachus schauinslandi), an endangered marine predator. We tested how Hawaiian monk seal feeding strategies change in response to ecological context, specifically prey size and prey location at different depths. Seven captive Hawaiian monk seals were fed five prey types across a continuum of sizes, and prey were presented at three depths to represent surface, pelagic, and benthic feeding. Hawaiian monk seals used suction feeding and biting strategies, and these strategies were associated with significant differences in behavior and kinematic performance. Hawaiian monk seals used suction feeding most frequently when targeting small to medium prey (0-79% of the seal's head length) but switched to biting when consuming large prey (>80% of the seal's head length). These results demonstrate that prey size drives the transition between suction feeding and biting strategies. Seals also switched strategies based on prey position in the water column, primarily using suction feeding when prey were benthic and pelagic, and biting when prey were at the water's surface. Overall, suction feeding was three to five times faster than biting, required a smaller gape, and used fewer jaw movements, allowing seals to quickly consume numerous small to medium sized prey. In contrast, biting was slower but resulted in the ability to target larger, potentially more energy rich prey. Our results show that Hawaiian monk seals exhibit flexibility in their use of different feeding strategies, which likely facilitates increased foraging success when feeding in spatially and temporally dynamic marine environments.
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Affiliation(s)
- Sarah S Kienle
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, CA 95060, USA
| | - Jezebel Powers
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, CA 95060, USA
| | - Traci Kendall
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, CA 95060, USA
| | - Beau Richter
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, CA 95060, USA
| | - Leann Castle
- Waikiki Aquarium, University of Hawai'i at Manoa, Honolulu, HI 96815, USA
| | - Gwen Lentes
- Waikiki Aquarium, University of Hawai'i at Manoa, Honolulu, HI 96815, USA
| | - Daniel Costa
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, CA 95060, USA
| | - Rita S Mehta
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, CA 95060, USA
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6
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Williams HJ, Taylor LA, Benhamou S, Bijleveld AI, Clay TA, de Grissac S, Demšar U, English HM, Franconi N, Gómez-Laich A, Griffiths RC, Kay WP, Morales JM, Potts JR, Rogerson KF, Rutz C, Spelt A, Trevail AM, Wilson RP, Börger L. Optimizing the use of biologgers for movement ecology research. J Anim Ecol 2019; 89:186-206. [PMID: 31424571 DOI: 10.1111/1365-2656.13094] [Citation(s) in RCA: 99] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Accepted: 08/08/2019] [Indexed: 10/26/2022]
Abstract
The paradigm-changing opportunities of biologging sensors for ecological research, especially movement ecology, are vast, but the crucial questions of how best to match the most appropriate sensors and sensor combinations to specific biological questions and how to analyse complex biologging data, are mostly ignored. Here, we fill this gap by reviewing how to optimize the use of biologging techniques to answer questions in movement ecology and synthesize this into an Integrated Biologging Framework (IBF). We highlight that multisensor approaches are a new frontier in biologging, while identifying current limitations and avenues for future development in sensor technology. We focus on the importance of efficient data exploration, and more advanced multidimensional visualization methods, combined with appropriate archiving and sharing approaches, to tackle the big data issues presented by biologging. We also discuss the challenges and opportunities in matching the peculiarities of specific sensor data to the statistical models used, highlighting at the same time the large advances which will be required in the latter to properly analyse biologging data. Taking advantage of the biologging revolution will require a large improvement in the theoretical and mathematical foundations of movement ecology, to include the rich set of high-frequency multivariate data, which greatly expand the fundamentally limited and coarse data that could be collected using location-only technology such as GPS. Equally important will be the establishment of multidisciplinary collaborations to catalyse the opportunities offered by current and future biologging technology. If this is achieved, clear potential exists for developing a vastly improved mechanistic understanding of animal movements and their roles in ecological processes and for building realistic predictive models.
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Affiliation(s)
- Hannah J Williams
- Department of Biosciences, College of Science, Swansea University, Swansea, UK
| | - Lucy A Taylor
- Save the Elephants, Nairobi, Kenya.,Department of Zoology, University of Oxford, Oxford, UK
| | - Simon Benhamou
- Centre d'Ecologie Fonctionnelle et Evolutive, CNRS Montpellier, Montpellier, France
| | - Allert I Bijleveld
- NIOZ Royal Netherlands Institute for Sea Research, Department of Coastal Systems, Utrecht University, Den Burg, The Netherlands
| | - Thomas A Clay
- School of Environmental Sciences, University of Liverpool, Liverpool, UK
| | - Sophie de Grissac
- Department of Biosciences, College of Science, Swansea University, Swansea, UK
| | - Urška Demšar
- School of Geography & Sustainable Development, University of St Andrews, St Andrews, UK
| | - Holly M English
- Department of Biosciences, College of Science, Swansea University, Swansea, UK
| | - Novella Franconi
- Department of Biosciences, College of Science, Swansea University, Swansea, UK
| | - Agustina Gómez-Laich
- Instituto de Biología de Organismos Marinos (IBIOMAR), CONICET, Puerto Madryn, Chubut, Argentina
| | - Rachael C Griffiths
- Department of Biosciences, College of Science, Swansea University, Swansea, UK
| | - William P Kay
- Department of Biosciences, College of Science, Swansea University, Swansea, UK
| | - Juan Manuel Morales
- Grupo de Ecología Cuantitativa, INIBIOMA-Universidad Nacional del Comahue, CONICET, Bariloche, Argentina
| | - Jonathan R Potts
- School of Mathematics and Statistics, University of Sheffield, Sheffield, UK
| | | | - Christian Rutz
- Centre for Biological Diversity, School of Biology, University of St Andrews, St Andrews, UK
| | - Anouk Spelt
- Department of Aerospace Engineering, University of Bristol, University Walk, UK
| | - Alice M Trevail
- School of Environmental Sciences, University of Liverpool, Liverpool, UK
| | - Rory P Wilson
- Department of Biosciences, College of Science, Swansea University, Swansea, UK
| | - Luca Börger
- Department of Biosciences, College of Science, Swansea University, Swansea, UK
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7
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Hurme E, Gurarie E, Greif S, Herrera M. LG, Flores-Martínez JJ, Wilkinson GS, Yovel Y. Acoustic evaluation of behavioral states predicted from GPS tracking: a case study of a marine fishing bat. MOVEMENT ECOLOGY 2019; 7:21. [PMID: 31223482 PMCID: PMC6567457 DOI: 10.1186/s40462-019-0163-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 05/23/2019] [Indexed: 06/09/2023]
Abstract
BACKGROUND Multiple methods have been developed to infer behavioral states from animal movement data, but rarely has their accuracy been assessed from independent evidence, especially for location data sampled with high temporal resolution. Here we evaluate the performance of behavioral segmentation methods using acoustic recordings that monitor prey capture attempts. METHODS We recorded GPS locations and ultrasonic audio during the foraging trips of 11 Mexican fish-eating bats, Myotis vivesi, using miniature bio-loggers. We then applied five different segmentation algorithms (k-means clustering, expectation-maximization and binary clustering, first-passage time, hidden Markov models, and correlated velocity change point analysis) to infer two behavioral states, foraging and commuting, from the GPS data. To evaluate the inference, we independently identified characteristic patterns of biosonar calls ("feeding buzzes") that occur during foraging in the audio recordings. We then compared segmentation methods on how well they correctly identified the two behaviors and if their estimates of foraging movement parameters matched those for locations with buzzes. RESULTS While the five methods differed in the median percentage of buzzes occurring during predicted foraging events, or true positive rate (44-75%), a two-state hidden Markov model had the highest median balanced accuracy (67%). Hidden Markov models and first-passage time predicted foraging flight speeds and turn angles similar to those measured at locations with feeding buzzes and did not differ in the number or duration of predicted foraging events. CONCLUSION The hidden Markov model method performed best at identifying fish-eating bat foraging segments; however, first-passage time was not significantly different and gave similar parameter estimates. This is the first attempt to evaluate segmentation methodologies in echolocating bats and provides an evaluation framework that can be used on other species.
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Affiliation(s)
- Edward Hurme
- Department of Biology, University of Maryland, College Park, MD 20742 USA
| | - Eliezer Gurarie
- Department of Biology, University of Maryland, College Park, MD 20742 USA
| | - Stefan Greif
- School of Zoology, Faculty of Life Sciences, Tel-Aviv University, 6997801 Tel-Aviv, Israel
- Sagol School of Neuroscience, Tel-Aviv University, 6997801 Tel-Aviv, Israel
| | - L. Gerardo Herrera M.
- Estación de Biología de Chamela, Instituto de Biología, Universidad Nacional Autónoma de México, 48980 San Patricio, Mexico
| | - José Juan Flores-Martínez
- Laboratorio de Sistemas de Información Geográfica, Departamento de Zoología, Instituto de Biología, Universidad Nacional Autónoma de México, 04510 Ciudad de México, Mexico
| | | | - Yossi Yovel
- School of Zoology, Faculty of Life Sciences, Tel-Aviv University, 6997801 Tel-Aviv, Israel
- Sagol School of Neuroscience, Tel-Aviv University, 6997801 Tel-Aviv, Israel
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8
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Kienle SS, Cacanindin A, Kendall T, Richter B, Ribeiro-French C, Castle L, Lentes G, Costa DP, Mehta RS. Hawaiian monk seals exhibit behavioral flexibility when targeting prey of different size and shape. ACTA ACUST UNITED AC 2019; 222:jeb.194985. [PMID: 30679244 DOI: 10.1242/jeb.194985] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 01/17/2019] [Indexed: 11/20/2022]
Abstract
Animals use diverse feeding strategies to capture and consume prey, with many species switching between strategies to accommodate different prey. Many marine animals exhibit behavioral flexibility when feeding to deal with spatial and temporal heterogeneity in prey resources. However, little is known about flexibility in the feeding behavior of many large marine predators. Here, we documented the feeding behavior and kinematics of the endangered Hawaiian monk seal (Neomonachus schauinslandi, n=7) through controlled feeding trials. Seals were fed multiple prey types (e.g. night smelt, capelin, squid and herring) that varied in size and shape to examine behavioral flexibility in feeding. Hawaiian monk seals primarily used suction feeding (91% of all feeding trials) across all prey types, but biting, specifically pierce feeding, was also observed (9% of all feeding trials). Suction feeding was characterized by shorter temporal events, a smaller maximum gape and gape angle, and a fewer number of jaw motions than pierce feeding; suction feeding kinematic performance was also more variable compared with pierce feeding. Seals showed behavioral flexibility in their use of the two strategies. Suction feeding was used most frequently when targeting small to medium sized prey and biting was used with increasing frequency on larger prey. The feeding kinematics differed between feeding strategies and prey types, showing that Hawaiian monk seals adjusted their behaviors to particular feeding contexts. Hawaiian monk seals are opportunistic marine predators and their ability to adapt their feeding strategy and behavior to specific foraging scenarios allows them to target diverse prey resources.
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Affiliation(s)
- Sarah S Kienle
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Ecology and Evolutionary Biology, Santa Cruz, CA 95060, USA
| | - Aliya Cacanindin
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Ecology and Evolutionary Biology, Santa Cruz, CA 95060, USA
| | - Traci Kendall
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Ecology and Evolutionary Biology, Santa Cruz, CA 95060, USA
| | - Beau Richter
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Ecology and Evolutionary Biology, Santa Cruz, CA 95060, USA
| | - Courtney Ribeiro-French
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Ecology and Evolutionary Biology, Santa Cruz, CA 95060, USA.,Monterey Bay Aquarium, Monterey, CA 93940, USA
| | - Leann Castle
- University of Hawai'i at Manoa, Waikiki Aquarium, Honolulu, HI 96815, USA
| | - Gwen Lentes
- University of Hawai'i at Manoa, Waikiki Aquarium, Honolulu, HI 96815, USA
| | - Daniel P Costa
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Ecology and Evolutionary Biology, Santa Cruz, CA 95060, USA
| | - Rita S Mehta
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Ecology and Evolutionary Biology, Santa Cruz, CA 95060, USA
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