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Lea M, Tainsh LW, Mattlin R, Torres L, Vinette Herrin K, Thompson DR, Hindell MA. The benthic-pelagic continuum: Age class and sex differences in the use of the vertical dimension by a rare pinniped. Ecol Evol 2023; 13:e10601. [PMID: 37928196 PMCID: PMC10622853 DOI: 10.1002/ece3.10601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 08/12/2023] [Accepted: 08/16/2023] [Indexed: 11/07/2023] Open
Abstract
Sea lions as a group, display strong site fidelity, and varying degrees of vulnerability to environmental change, disease and fisheries interactions. One of the rarest pinnipeds, the New Zealand sea lion (NZSL, Phocarctos hookeri) has a very restricted breeding range. At Campbell Island/Motu Ihupuku, one of the two primary breeding sites, at-sea foraging behaviour is unknown. We hypothesised that NZSL of various sex and age classes would utilise the water column differently due to differing physiological constraints and therefore have different accessibility to prey resources. We tested whether sea lion diving behaviour varied in relation to (i) age and sex class, (ii) time of day and (iii) water depth. We also hypothesised that the proportion of benthic/pelagic diving, and consequently risk of fisheries interaction, would vary in relation to age and sex. Satellite telemetry tags were deployed on 25 NZSL from a range of age/sex classes recording dive depth, duration and location. Adult females and juveniles used inshore, benthic habitats, while sub-adult males also utilised benthic habitats, they predominantly used pelagic habitat at greater distances from the island. Adult females and juveniles exhibited shorter dives than the same age/sex classes at the Auckland Islands, suggesting a lower dive effort for these age/sex classes at Campbell Island/Motu Ihupuku. Adult females dived more frequently than other age/sex classes, likely operating closer to their physiological limits; however, further data for this age class is needed. Sub-adult male use of pelagic prey may increase their exposure to mid-water trawls; however, further research detailing the degree of spatial overlap with fisheries is required. This study highlights the utility of spatially explicit dive data to predict vertical habitat use, niche separation of various age and sex classes of marine predators and attribute potential fisheries interaction risk in relation to predator habitat use.
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Affiliation(s)
- Mary‐Anne Lea
- Institute for Marine and Antarctic StudiesUniversity of TasmaniaHobartTasmaniaAustralia
| | - Lachlan W. Tainsh
- Institute for Marine and Antarctic StudiesUniversity of TasmaniaHobartTasmaniaAustralia
| | - Rob Mattlin
- Marine Wildlife Research, LtdNelsonNew Zealand
| | - Leigh Torres
- Department of Fisheries and Wildlife, Marine Mammal Institute, Hatfield Marine Science CenterOregon State UniversityNewportOregonUSA
| | | | | | - Mark A. Hindell
- Institute for Marine and Antarctic StudiesUniversity of TasmaniaHobartTasmaniaAustralia
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2
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Costa DP, Favilla AB. Field physiology in the aquatic realm: ecological energetics and diving behavior provide context for elucidating patterns and deviations. J Exp Biol 2023; 226:jeb245832. [PMID: 37843467 DOI: 10.1242/jeb.245832] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2023]
Abstract
Comparative physiology has developed a rich understanding of the physiological adaptations of organisms, from microbes to megafauna. Despite extreme differences in size and a diversity of habitats, general patterns are observed in their physiological adaptations. Yet, many organisms deviate from the general patterns, providing an opportunity to understand the importance of ecology in determining the evolution of unusual adaptations. Aquatic air-breathing vertebrates provide unique study systems in which the interplay between ecology, physiology and behavior is most evident. They must perform breath-hold dives to obtain food underwater, which imposes a physiological constraint on their foraging time as they must resurface to breathe. This separation of two critical resources has led researchers to investigate these organisms' physiological adaptations and trade-offs. Addressing such questions on large marine animals is best done in the field, given the difficulty of replicating the environment of these animals in the lab. This Review examines the long history of research on diving physiology and behavior. We show how innovative technology and the careful selection of research animals have provided a holistic understanding of diving mammals' physiology, behavior and ecology. We explore the role of the aerobic diving limit, body size, oxygen stores, prey distribution and metabolism. We then identify gaps in our knowledge and suggest areas for future research, pointing out how this research will help conserve these unique animals.
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Affiliation(s)
- Daniel P Costa
- Institute of Marine Sciences, Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, CA 95060, USA
| | - Arina B Favilla
- Institute of Marine Sciences, Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, CA 95060, USA
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3
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Noren SR, Rosen DAS. What are the Metabolic Rates of Marine Mammals and What Factors Impact this Value: A review. CONSERVATION PHYSIOLOGY 2023; 11:coad077. [PMID: 37790839 PMCID: PMC10545007 DOI: 10.1093/conphys/coad077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Revised: 08/22/2023] [Accepted: 09/14/2023] [Indexed: 10/05/2023]
Abstract
Over the past several decades, scientists have constructed bioenergetic models for marine mammals to assess potential population-level consequences following exposure to a disturbance, stressor, or environmental change, such as under the Population Consequences of Disturbance (pCOD) framework. The animal's metabolic rate (rate of energy expenditure) is a cornerstone for these models, yet the cryptic lifestyles of marine mammals, particularly cetaceans, have limited our ability to quantify basal (BMR) and field (FMR) metabolic rates using accepted 'gold standard' approaches (indirect calorimeter via oxygen consumption and doubly labeled water, respectively). Thus, alternate methods have been used to quantify marine mammal metabolic rates, such as extrapolating from known allometric relationships (e.g. Kleiber's mouse to elephant curve) and developing predictive relationships between energy expenditure and physiological or behavioral variables. To understand our current knowledge of marine mammal metabolic rates, we conducted a literature review (1900-2023) to quantify the magnitude and variation of metabolic rates across marine mammal groups. A compilation of data from studies using 'gold standard' methods revealed that BMR and FMR of different marine mammal species ranges from 0.2 to 3.6 and 1.1 to 6.1 x Kleiber, respectively. Mean BMR and FMR varied across taxa; for both measures odontocete levels were intermediate to higher values for otariids and lower values of phocids. Moreover, multiple intrinsic (e.g. age, sex, reproduction, molt, individual) and extrinsic (e.g. food availability, water temperature, season) factors, as well as individual behaviors (e.g. animal at water's surface or submerged, activity level, dive effort and at-sea behaviors) impact the magnitude of these rates. This review provides scientists and managers with a range of reliable metabolic rates for several marine mammal groups as well as an understanding of the factors that influence metabolism to improve the discernment for inputs into future bioenergetic models.
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Affiliation(s)
- S R Noren
- Institute of Marine Science, University of California Santa Cruz, Center for Ocean Health, 115 McAllister Way, Santa Cruz, CA 95060, USA
| | - David A S Rosen
- Marine Mammal Research Unit, Institute for the Oceans and Fisheries, University of British Columbia, 2202 Main Mall, Vancouver, BC, Canada V6T 1Z4
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Cole MR, Ware C, McHuron EA, Costa DP, Ponganis PJ, McDonald BI. Deep dives and high tissue density increase mean dive costs in California sea lions (Zalophus californianus). J Exp Biol 2023; 226:jeb246059. [PMID: 37345474 DOI: 10.1242/jeb.246059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 06/14/2023] [Indexed: 06/23/2023]
Abstract
Diving is central to the foraging strategies of many marine mammals and seabirds. Still, the effect of dive depth on foraging cost remains elusive because energy expenditure is difficult to measure at fine temporal scales in wild animals. We used depth and acceleration data from eight lactating California sea lions (Zalophus californianus) to model body density and investigate the effect of dive depth and tissue density on rates of energy expenditure. We calculated body density in 5 s intervals from the rate of gliding descent. We modeled body density across depth in each dive, revealing high tissue densities and diving lung volumes (DLVs). DLV increased with dive depth in four individuals. We used the buoyancy calculated from dive-specific body-density models and drag calculated from swim speed to estimate metabolic power and cost of transport in 5 s intervals during descents and ascents. Deeper dives required greater mean power for round-trip vertical transit, especially in individuals with higher tissue density. These trends likely follow from increased mean swim speed and buoyant hinderance that increasingly outweighs buoyant aid in deeper dives. This suggests that deep diving is either a 'high-cost, high-reward' strategy or an energetically expensive option to access prey when prey in shallow waters are limited, and that poor body condition may increase the energetic costs of deep diving. These results add to our mechanistic understanding of how foraging strategy and body condition affect energy expenditure in wild breath-hold divers.
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Affiliation(s)
- Mason R Cole
- Moss Landing Marine Laboratories, San Jose State University, 8272 Moss Landing Rd, Moss Landing, CA 95039, USA
| | - Colin Ware
- Center for Coastal and Ocean Mapping, University of New Hampshire, Durham, NH 03924, USA
| | - Elizabeth A McHuron
- Cooperative Institute for Climate, Ocean, and Ecosystem Studies, University of Washington, Seattle, WA 98105, USA
| | - Daniel P Costa
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA 95064, USA
| | - Paul J Ponganis
- Scripps Institution of Oceanography, University of California San Diego, Center for Marine Biodiversity and Biomedicine, 8655 Kennel Way, La Jolla, CA 92037, USA
| | - Birgitte I McDonald
- Moss Landing Marine Laboratories, San Jose State University, 8272 Moss Landing Rd, Moss Landing, CA 95039, USA
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5
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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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6
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Valenzuela-Toro AM, Mehta R, Pyenson ND, Costa DP, Koch PL. Feeding morphology and body size shape resource partitioning in an eared seal community. Biol Lett 2023; 19:20220534. [PMID: 36883314 PMCID: PMC9993223 DOI: 10.1098/rsbl.2022.0534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023] Open
Abstract
Body size and feeding morphology influence how animals partition themselves within communities. We tested the relationships among sex, body size, skull morphology and foraging in sympatric otariids (eared seals) from the eastern North Pacific Ocean, the most diverse otariid community in the world. We recorded skull measurements and stable carbon (δ13C) and nitrogen (δ15N) isotope values (proxies for foraging) from museum specimens in four sympatric species: California sea lions (Zalophus californianus), Steller sea lions (Eumetopias jubatus), northern fur seals (Callorhinus ursinus) and Guadalupe fur seals (Arctocephalus townsendi). Species and sexes had statistical differences in size, skull morphology and foraging significantly affecting the δ13C values. Sea lions had higher δ13C values than fur seals, and males of all species had higher values than females. The δ15N values were correlated with species and feeding morphology; individuals with stronger bite forces had higher δ15N values. We also found a significant community-wide correlation between skull length (indicator of body length), and foraging, with larger individuals having nearshore habitat preferences, and consuming higher trophic level prey than smaller individuals. Still, there was no consistent association between these traits at the intraspecific level, indicating that other factors might account for foraging variability.
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Affiliation(s)
- Ana M Valenzuela-Toro
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA 95060, USA.,Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560, USA
| | - Rita Mehta
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA 95060, USA
| | - Nicholas D Pyenson
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA 95060, USA.,Department of Paleontology and Geology, Burke Museum of Natural History and Culture, Seattle, WA 98105, USA
| | - Daniel P Costa
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA 95060, USA.,Institute of Marine Sciences, University of California Santa Cruz, Santa Cruz, CA 95064, USA
| | - Paul L Koch
- Department of Earth and Planetary Sciences, University of California Santa Cruz, Santa Cruz, CA 95064, USA
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7
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Botha JA, Trueman CN, Kirkman SP, Arnould JPY, Lombard AT, Connan M, Hofmeyr GJG, Seakamela SM, Pistorius PA. Geographical, temporal, and individual-based differences in the trophic ecology of female Cape fur seals. Ecol Evol 2023; 13:e9790. [PMID: 36789339 PMCID: PMC9909003 DOI: 10.1002/ece3.9790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 12/30/2022] [Accepted: 01/10/2023] [Indexed: 02/11/2023] Open
Abstract
Information on resource use and trophic dynamics of marine predators is important for understanding their role in ecosystem functioning and predicting population-level responses to environmental change. Where separate populations experience different local environmental conditions, geographic variability in their foraging ecology is often expected. Within populations, individuals also vary in morphology, physiology, and experience, resulting in specialization in resource use. In this context, isotopic compositions of incrementally grown tissues such as keratinous hairs offer a valuable opportunity to study long-term variation in resource and habitat use. We investigated the trophic ecology of female Cape fur seals (Arctocephalus pusillus pusillus) using carbon and nitrogen isotopic compositions of serially sampled whiskers collected at four breeding sites along the coast of South Africa. Drawing on over 900 isotopic measurements, we assessed geographic variability in isotopic niche width between colonies and the degree of individual specialization. We found slight, but clear geographic differences in isotopic ratios and isotopic niche widths, seemingly related to ecological setting, with niche widths being proportional to the area of available shelf and shelf-slope habitat surrounding the colony. We further identified periodic oscillations in isotopic ratios, which likely reflect temporal patterns in foraging distribution and prey type, linked to shifts in the availability of prey resources and their interaction with constraints on individual females throughout their breeding cycle. Finally, individual specialization indices revealed that each of the study populations contain specialist individuals that utilize only a small subset of the total population niche width. The degree of individual specialization was, however, not consistent across colonies and may reflect an interactive influence between density-dependent effects and habitat heterogeneity. Overall, this study provides important information on the trophic ecology of Cape fur seals breeding in South Africa and highlights the need to consider geographic and individual variability when assessing the foraging ecology of marine predators.
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Affiliation(s)
- Jonathan A. Botha
- Marine Apex Predator Research Unit (MAPRU), Department of Zoology and Institute for Coastal and Marine ResearchNelson Mandela UniversityGqeberhaSouth Africa
| | - Clive N. Trueman
- Ocean and Earth Science, SouthamptonUniversity of SouthamptonSouthamptonUK
| | - Stephen P. Kirkman
- Marine Apex Predator Research Unit (MAPRU), Department of Zoology and Institute for Coastal and Marine ResearchNelson Mandela UniversityGqeberhaSouth Africa
- Oceans and Coast Research, Department of ForestryFisheries and the EnvironmentCape TownSouth Africa
| | - John P. Y. Arnould
- Faculty of Science, Engineering and Built EnvironmentDeakin UniversityBurwoodVictoriaAustralia
| | - Amanda T. Lombard
- Marine Apex Predator Research Unit (MAPRU), Department of Zoology and Institute for Coastal and Marine ResearchNelson Mandela UniversityGqeberhaSouth Africa
| | - Maëlle Connan
- Marine Apex Predator Research Unit (MAPRU), Department of Zoology and Institute for Coastal and Marine ResearchNelson Mandela UniversityGqeberhaSouth Africa
| | - G. J. Greg Hofmeyr
- Marine Apex Predator Research Unit (MAPRU), Department of Zoology and Institute for Coastal and Marine ResearchNelson Mandela UniversityGqeberhaSouth Africa
- Port Elizabeth Museum at BayworldGqeberhaSouth Africa
| | - S. Mduduzi Seakamela
- Oceans and Coast Research, Department of ForestryFisheries and the EnvironmentCape TownSouth Africa
| | - Pierre A. Pistorius
- Marine Apex Predator Research Unit (MAPRU), Department of Zoology and Institute for Coastal and Marine ResearchNelson Mandela UniversityGqeberhaSouth Africa
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McHuron EA, Adamczak S, Arnould JPY, Ashe E, Booth C, Bowen WD, Christiansen F, Chudzinska M, Costa DP, Fahlman A, Farmer NA, Fortune SME, Gallagher CA, Keen KA, Madsen PT, McMahon CR, Nabe-Nielsen J, Noren DP, Noren SR, Pirotta E, Rosen DAS, Speakman CN, Villegas-Amtmann S, Williams R. Key questions in marine mammal bioenergetics. CONSERVATION PHYSIOLOGY 2022; 10:coac055. [PMID: 35949259 PMCID: PMC9358695 DOI: 10.1093/conphys/coac055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 06/28/2022] [Accepted: 07/20/2022] [Indexed: 06/15/2023]
Abstract
Bioenergetic approaches are increasingly used to understand how marine mammal populations could be affected by a changing and disturbed aquatic environment. There remain considerable gaps in our knowledge of marine mammal bioenergetics, which hinder the application of bioenergetic studies to inform policy decisions. We conducted a priority-setting exercise to identify high-priority unanswered questions in marine mammal bioenergetics, with an emphasis on questions relevant to conservation and management. Electronic communication and a virtual workshop were used to solicit and collate potential research questions from the marine mammal bioenergetic community. From a final list of 39 questions, 11 were identified as 'key' questions because they received votes from at least 50% of survey participants. Key questions included those related to energy intake (prey landscapes, exposure to human activities) and expenditure (field metabolic rate, exposure to human activities, lactation, time-activity budgets), energy allocation priorities, metrics of body condition and relationships with survival and reproductive success and extrapolation of data from one species to another. Existing tools to address key questions include labelled water, animal-borne sensors, mark-resight data from long-term research programs, environmental DNA and unmanned vehicles. Further validation of existing approaches and development of new methodologies are needed to comprehensively address some key questions, particularly for cetaceans. The identification of these key questions can provide a guiding framework to set research priorities, which ultimately may yield more accurate information to inform policies and better conserve marine mammal populations.
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Affiliation(s)
- Elizabeth A McHuron
- Corresponding author: Cooperative Institute for Climate, Ocean, and Ecosystem Studies, University of Washington, WA, 98195, USA.
| | - Stephanie Adamczak
- Ecology and Evolutionary Biology Department, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
| | - John P Y Arnould
- School of Life and Environmental Sciences, Deakin University, Burwood, VIC 3125, Australia
| | - Erin Ashe
- Oceans Initiative, Seattle, WA, 98102, USA
| | - Cormac Booth
- SMRU Consulting, Scottish Oceans Institute, University of St. Andrews, St. Andrews KY16 8LB, UK
| | - W Don Bowen
- Biology Department, Dalhousie University, Halifax, NS B3H 4R2, Canada
- Population Ecology Division, Bedford Institute of Oceanography, Dartmouth, NS B2Y 4A2, Canada
| | - Fredrik Christiansen
- Aarhus Institute of Advanced Studies, 8000 Aarhus C, Denmark
- Zoophysiology, Department of Biology, Aarhus University, 8000 Aarhus C, Denmark
- Center for Sustainable Aquatic Ecosystems, Harry Butler Institute, Murdoch, Murdoch University, WA 6150, Australia
| | - Magda Chudzinska
- SMRU Consulting, Scottish Oceans Institute, University of St. Andrews, St. Andrews KY16 8LB, UK
- Sea Mammal Research Unit, Scottish Oceans Institute, University of St. Andrews, St. Andrews KY16 9XL, UK
| | - Daniel P Costa
- Ecology and Evolutionary Biology Department, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
| | - Andreas Fahlman
- Fundación Oceanogràfic de la Comunitat Valenciana, 46005 Valencia, Spain
- Kolmården Wildlife Park, 618 92 Kolmården, Sweden
| | - Nicholas A Farmer
- NOAA/National Marine Fisheries Service, Southeast Regional Office, St. Petersburg, FL, 33701, USA
| | - Sarah M E Fortune
- Department of Oceanography, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Cara A Gallagher
- Plant Ecology and Nature Conservation, University of Potsdam, 14476 Potsdam, Germany
| | - Kelly A Keen
- Ecology and Evolutionary Biology Department, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
| | - Peter T Madsen
- Zoophysiology, Department of Biology, Aarhus University, 8000 Aarhus C, Denmark
| | - Clive R McMahon
- IMOS Animal Tagging, Sydney Institute of Marine Science, Mosman, NSW 2088, Australia
| | | | - Dawn P Noren
- Conservation Biology Division, Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, WA, 98112, USA
| | - Shawn R Noren
- Institute of Marine Science, University of California Santa Cruz, Santa Cruz, CA, 95060, USA
| | - Enrico Pirotta
- Centre for Research into Ecological and Environmental Modelling, University of St. Andrews, St. Andrews KY16 9LZ, UK
| | - David A S Rosen
- Institute for Oceans and Fisheries, University of British Columbia, Vancouver, BC V6T 1ZA, Canada
| | - Cassie N Speakman
- School of Life and Environmental Sciences, Deakin University, Burwood, VIC 3125, Australia
| | - Stella Villegas-Amtmann
- Ecology and Evolutionary Biology Department, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
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9
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Seguel M, Molina-Burgos BE, Perez-Venegas DJ, Chiang G, Harrod C, DeRango E, Paves H. Shifts in maternal foraging strategies during pregnancy promote offspring health and survival in a marine top predator. Oecologia 2022; 199:343-354. [PMID: 35678930 DOI: 10.1007/s00442-022-05200-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 05/21/2022] [Indexed: 11/26/2022]
Abstract
The success of maternal foraging strategies during the rearing period can greatly impact the physiology and survival of dependent offspring. Surprisingly though, little is known on the fitness consequences of foraging strategies during the foetal period. In this study, we characterized variation in maternal foraging strategy throughout pregnancy in a marine top predator (South American fur seal, Arctocephalus australis), and asked if these shifts predicted neonatal health and postnatal survival. We found that during early pregnancy all pregnant females belonged to a single, homogenized foraging niche without evident clusters. Intriguingly though, during late pregnancy, individual fur seal mothers diverged into two distinct foraging niches characterized by a benthic-nearshore and a pelagic-offshore strategy. Females that shifted towards the benthic-nearshore strategy gave birth to pups with greater body mass, higher plasmatic levels of glucose and lower levels of blood urea nitrogen. The pups born to these benthic females were eight times more likely to survive compared to females using the pelagic-offshore foraging strategy during late pregnancy. These survival effects were mediated primarily by the impact of foraging strategies on neonatal glucose independent of protein metabolic profile and body mass. Benthic-nearshore foraging strategies during late pregnancy potentially allow for the greater maternal transfer of glucose to the foetus, leading to higher chances of neonatal survival. These results call for a deeper understanding of the balance between resource acquisition and allocation provided by distinct foraging polymorphisms during critical life-history periods, and how this trade-off may be adaptive under certain environmental conditions.
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Affiliation(s)
- Mauricio Seguel
- Department of Pathobiology, Ontario Veterinary College, University of Guelph, 419 Gordon St, Guelph, ON, N1G2W1, Canada.
| | - Blanca E Molina-Burgos
- Facultad de Medicina Veterinaria y Agronomía, Universidad de las Americas, Manuel Montt 948, 7500000, Santiago, Chile
- Centro de Investigación Para La Sustentabilidad, Facultad de Ciencias de La Vida, Universidad Andres Bello, 8370251, Santiago, Chile
| | - Diego J Perez-Venegas
- Centro de Investigación y Gestión de Recursos Naturales (CIGREN), Instituto de Biología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Gustavo Chiang
- Departamento de Ecología y Biodiversidad and Centro de Investigación Para La Sustentabilidad (CIS), Facultad de Ciencias de La Vida, Universidad Andrés Bello, 8370251, Santiago, Chile
| | - Chris Harrod
- University of Antofagasta Stable Isotope Facility, University of Antofagasta, Antofagasta, Chile
- Instituto de Ciencias Naturales Alexander Von Humboldt, Universidad de Antofagasta, Antofagasta, Chile
- Nucleo Milenio INVASAL, Concepción, Chile
| | - Eugene DeRango
- Department of Animal Behaviour, Bielefeld University, Bielefeld, Germany
| | - Hector Paves
- Departamento de Ciencias Básicas, Facultad de Ciencias, Universidad Santo Tomas, Osorno, Chile
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10
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Cárdenas‐Alayza S, Torres DA, Gutiérrez D, Tremblay Y. Resource partitioning as a mechanism for trophic segregation in sympatric otariids from the productive upwelling Peruvian Humboldt Current System. AUSTRAL ECOL 2022. [DOI: 10.1111/aec.13158] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Susana Cárdenas‐Alayza
- Centro para la Sostenibilidad Ambiental Universidad Peruana Cayetano Heredia Lima 15074 Peru
- Laboratorio de Ciencias del Mar Universidad Peruana Cayetano Heredia Lima Peru
- UMR 248 MARBEC: IRD CNRS Ifremer Univ. Montpellier Sète cedex France
| | - Daniel A. Torres
- Centro para la Sostenibilidad Ambiental Universidad Peruana Cayetano Heredia Lima 15074 Peru
| | - Dimitri Gutiérrez
- Laboratorio de Ciencias del Mar Universidad Peruana Cayetano Heredia Lima Peru
- Programa Maestría en Ciencias del Mar Universidad Peruana Cayetano Heredia Lima Peru
| | - Yann Tremblay
- UMR 248 MARBEC: IRD CNRS Ifremer Univ. Montpellier Sète cedex France
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11
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OUP accepted manuscript. J Mammal 2022. [DOI: 10.1093/jmammal/gyac023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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12
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Rimbach R, Amireh A, Allen A, Hare B, Guarino E, Kaufman C, Salomons H, Pontzer H. Total energy expenditure of bottlenose dolphins (Tursiops truncatus) of different ages. J Exp Biol 2021; 224:271194. [PMID: 34350948 DOI: 10.1242/jeb.242218] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 06/30/2021] [Indexed: 11/20/2022]
Abstract
Marine mammals are thought to have an energetically expensive lifestyle because endothermy is costly in marine environments. However, measurements of total energy expenditure (TEE; kcal day-1) are available only for a limited number of marine mammals, because large body size and inaccessible habitats make TEE measurements expensive and difficult to obtain for many taxa. We measured TEE in 10 adult common bottlenose dolphins (Tursiops truncatus) living in natural seawater lagoons at two facilities (Dolphin Research Center and Dolphin Quest) using the doubly labeled water method. We assessed the relative effects of body mass, age and physical activity on TEE. We also examined whether TEE of bottlenose dolphins, and more generally of marine mammals, differs from that expected for their body mass compared with other eutherian mammals, using phylogenetic least squares (PGLS) regressions. There were no differences in body mass or TEE (unadjusted TEE and TEE adjusted for fat-free mass) between dolphins from the two facilities. Our results show that adjusted TEE decreased and fat mass increased with age. Different measures of activity were not related to age, body fat or adjusted TEE. Both PGLS and the non-phylogenetic linear regression indicate that marine mammals have an elevated TEE compared with that of terrestrial mammals. However, bottlenose dolphins expended 17.1% less energy than other marine mammals of similar body mass. The two oldest dolphins (>40 years) showed a lower TEE, similar to the decline in TEE seen in older humans. To our knowledge, this is the first study to show an age-related metabolic decline in a large non-human mammal.
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Affiliation(s)
- Rebecca Rimbach
- Evolutionary Anthropology, Duke University, Durham, NC 27708, USA.,School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, WITS 2050, South Africa
| | - Ahmad Amireh
- Evolutionary Anthropology, Duke University, Durham, NC 27708, USA
| | - Austin Allen
- Duke University Marine Lab, Beaufort, NC 28516, USA
| | - Brian Hare
- Evolutionary Anthropology, Duke University, Durham, NC 27708, USA
| | | | - Chana Kaufman
- Evolutionary Anthropology, Duke University, Durham, NC 27708, USA
| | - Hannah Salomons
- Evolutionary Anthropology, Duke University, Durham, NC 27708, USA
| | - Herman Pontzer
- Evolutionary Anthropology, Duke University, Durham, NC 27708, USA.,Duke Global Health Institute, Duke University, Durham, NC 27710, USA
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13
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Hooker SK, Andrews RD, Arnould JPY, Bester MN, Davis RW, Insley SJ, Gales NJ, Goldsworthy SD, McKnight JC. Fur seals do, but sea lions don't - cross taxa insights into exhalation during ascent from dives. Philos Trans R Soc Lond B Biol Sci 2021; 376:20200219. [PMID: 34121462 PMCID: PMC8200655 DOI: 10.1098/rstb.2020.0219] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/07/2020] [Indexed: 11/12/2022] Open
Abstract
Management of gases during diving is not well understood across marine mammal species. Prior to diving, phocid (true) seals generally exhale, a behaviour thought to assist with the prevention of decompression sickness. Otariid seals (fur seals and sea lions) have a greater reliance on their lung oxygen stores, and inhale prior to diving. One otariid, the Antarctic fur seal (Arctocephalus gazella), then exhales during the final 50-85% of the return to the surface, which may prevent another gas management issue: shallow-water blackout. Here, we compare data collected from animal-attached tags (video cameras, hydrophones and conductivity sensors) deployed on a suite of otariid seal species to examine the ubiquity of ascent exhalations for this group. We find evidence for ascent exhalations across four fur seal species, but that such exhalations are absent for three sea lion species. Fur seals and sea lions are no longer genetically separated into distinct subfamilies, but are morphologically distinguished by the thick underfur layer of fur seals. Together with their smaller size and energetic dives, we suggest their air-filled fur might underlie the need to perform these exhalations, although whether to reduce buoyancy and ascent speed, for the avoidance of shallow-water blackout or to prevent other cardiovascular management issues in their diving remains unclear. This article is part of the theme issue 'Measuring physiology in free-living animals (Part I)'.
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Affiliation(s)
- Sascha K. Hooker
- Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, Fife KY16 8LB, UK
| | | | - John P. Y. Arnould
- School of Life and Environmental Sciences, Deakin University, Burwood, Victoria 3125, Australia
| | - Marthán N. Bester
- Mammal Research Institute, University of Pretoria, Hatfield 0028, Gauteng, South Africa
| | - Randall W. Davis
- Department of Marine Biology, Texas A&M University, Galveston, TX 77553, USA
| | - Stephen J. Insley
- Department of Biology, University of Victoria, Victoria, British Columbia, Canada, V8P 5C2
- Wildlife Conservation Society Canada, Whitehorse, Yukon Territory, Canada, Y1A 0E9
| | - Nick J. Gales
- Australian Antarctic Division, Kingston, Tasmania 7050, Australia
| | - Simon D. Goldsworthy
- South Australian Research and Development Institute, West Beach, South Australia 5024, Australia
- School of Biological Sciences, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - J. Chris McKnight
- Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, Fife KY16 8LB, UK
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14
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Moorhead SG, Gallagher AJ, Merly L, Hammerschlag N. Variation of body condition and plasma energy substrates with life stage, sex, and season in wild-sampled nurse sharks Ginglymostoma cirratum. JOURNAL OF FISH BIOLOGY 2021; 98:680-693. [PMID: 33161578 DOI: 10.1111/jfb.14612] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 10/23/2020] [Accepted: 11/07/2020] [Indexed: 06/11/2023]
Abstract
Reported here are the relationships among morphological (i.e., body condition) and biochemical (i.e., plasma concentrations of triglycerides, cholesterol, free fatty acids, and ketone bodies and ketone body ratios) parameters related to energy storage and use, as well as the variation of such parameters, for 107 free-ranging nurse sharks Ginglymostoma cirratum sampled off South Florida. Immature G. cirratum exhibited a higher variance in body condition, plasma free fatty acid concentrations and ketone body ratios compared to adults. Mature female G. cirratum had significantly higher body condition than mature males, driven by a seasonal increase in mature female body condition during the wet season. Mature male G. cirratum showed a decrease in the ketone body β-hydroxybutyric acid during the dry season. Taken together, this study provides a baseline assessment of body condition and internal physiological state for a data-poor marine species and demonstrates significant ontogenetic, sexual and seasonal variation in G. cirratum energetic state. As concluded by other studies of energy metabolism in free-ranging sharks, this research highlights the importance of considering intraspecific patterns and sampling context for inferring the drivers of variation.
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Affiliation(s)
- Shannon G Moorhead
- Department of Marine Ecosystems and Society, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida, USA
| | - Austin J Gallagher
- Beneath the Waves, Herndon, Virginia, USA
- Fish Ecology and Conservation Physiology Laboratory, Carleton University, Ottawa, Ontario, Canada
| | - Liza Merly
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida, USA
| | - Neil Hammerschlag
- Department of Marine Ecosystems and Society, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida, USA
- Leonard and Jayne Abess Center for Ecosystem Science and Policy, University of Miami, Coral Gables, Florida, USA
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15
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Schwarz JFL, Mews S, DeRango EJ, Langrock R, Piedrahita P, Páez-Rosas D, Krüger O. Individuality counts: A new comprehensive approach to foraging strategies of a tropical marine predator. Oecologia 2021; 195:313-325. [PMID: 33491108 PMCID: PMC7882564 DOI: 10.1007/s00442-021-04850-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 01/04/2021] [Indexed: 11/24/2022]
Abstract
Foraging strategies are of great ecological interest, as they have a strong impact on the fitness of an individual and can affect its ability to cope with a changing environment. Recent studies on foraging strategies show a higher complexity than previously thought due to intraspecific variability. To reliably identify foraging strategies and describe the different foraging niches they allow individual animals to realize, high-resolution multivariate approaches which consider individual variation are required. Here we dive into the foraging strategies of Galápagos sea lions (Zalophus wollebaeki), a tropical predator confronted with substantial annual variation in sea surface temperature. This affects prey abundance, and El Niño events, expected to become more frequent and severe with climate change, are known to have dramatic effects on sea lions. This study used high-resolution measures of depth, GPS position and acceleration collected from 39 lactating sea lion females to analyze their foraging strategies at an unprecedented level of detail using a novel combination of automated broken stick algorithm, hierarchical cluster analysis and individually fitted multivariate hidden Markov models. We found three distinct foraging strategies (pelagic, benthic, and night divers), which differed in their horizontal, vertical and temporal distribution, most likely corresponding to different prey species, and allowed us to formulate hypotheses with regard to adaptive values under different environmental scenarios. We demonstrate the advantages of our multivariate approach and inclusion of individual variation to reliably gain a deeper understanding of the adaptive value and ecological relevance of foraging strategies of marine predators in dynamic environments.
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Affiliation(s)
- Jonas F L Schwarz
- Department of Animal Behaviour, Bielefeld University, Bielefeld, Germany.
| | - Sina Mews
- Department of Business Administration and Economics, Bielefeld University, Bielefeld, Germany
| | - Eugene J DeRango
- Department of Animal Behaviour, Bielefeld University, Bielefeld, Germany
| | - Roland Langrock
- Department of Business Administration and Economics, Bielefeld University, Bielefeld, Germany
| | - Paolo Piedrahita
- Facultad de Ciencias de La Vida, Escuela Superior Politécnica del Litoral, Guayaquil, Ecuador
| | - Diego Páez-Rosas
- Galápagos Science Center, Universidad San Francisco de Quito, Puerto Baquerizo Moreno, Ecuador.,Dirección Parque Nacional Galápagos, Unidad Técnica Operativa San Cristóbal, Puerto Baquerizo Moreno, Ecuador
| | - Oliver Krüger
- Department of Animal Behaviour, Bielefeld University, Bielefeld, Germany
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16
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Ladds M, Rosen D, Gerlinsky C, Slip D, Harcourt R. Diving deep into trouble: the role of foraging strategy and morphology in adapting to a changing environment. CONSERVATION PHYSIOLOGY 2020; 8:coaa111. [PMID: 34168880 PMCID: PMC8218901 DOI: 10.1093/conphys/coaa111] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Revised: 05/02/2020] [Accepted: 11/24/2020] [Indexed: 06/12/2023]
Abstract
Physiology places constraints on an animal's ability to forage and those unable to adapt to changing conditions may face increased challenges to reproduce and survive. As the global marine environment continues to change, small, air-breathing, endothermic marine predators such as otariids (fur seals and sea lions) and particularly females, who are constrained by central place foraging during breeding, may experience increased difficulties in successfully obtaining adequate food resources. We explored whether physiological limits of female otariids may be innately related to body morphology (fur seals vs sea lions) and/or dictate foraging strategies (epipelagic vs mesopelagic or benthic). We conducted a systematic review of the increased body of literature since the original reviews of Costa et al. (When does physiology limit the foraging behaviour of freely diving mammals? Int Congr Ser 2004;1275:359-366) and Arnould and Costa (Sea lions in drag, fur seals incognito: insights from the otariid deviants. In Sea Lions of the World Fairbanks. Alaska Sea Grant College Program, Alaska, USA, pp. 309-324, 2006) on behavioural (dive duration and depth) and physiological (total body oxygen stores and diving metabolic rates) parameters. We estimated calculated aerobic dive limit (cADL-estimated duration of aerobic dives) for species and used simulations to predict the proportion of dives that exceeded the cADL. We tested whether body morphology or foraging strategy was the primary predictor of these behavioural and physiological characteristics. We found that the foraging strategy compared to morphology was a better predictor of most parameters, including whether a species was more likely to exceed their cADL during a dive and the ratio of dive time to cADL. This suggests that benthic and mesopelagic divers are more likely to be foraging at their physiological capacity. For species operating near their physiological capacity (regularly exceeding their cADL), the ability to switch strategies is limited as the cost of foraging deeper and longer is disproportionally high, unless it is accompanied by physiological adaptations. It is proposed that some otariids may not have the ability to switch foraging strategies and so be unable adapt to a changing oceanic ecosystem.
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Affiliation(s)
- Monique Ladds
- Marine Ecosystems Team, Department of Conservation, Wellington 6011, New Zealand
- Marine Predator Research Group, Department of Biological Sciences,
Macquarie University, North Ryde 2113, Australia
| | - David Rosen
- Marine Mammal Research Unit, Institute for the Oceans and Fisheries,
University of British Columbia, Vancouver V6T 1Z4, Canada
| | - Carling Gerlinsky
- Marine Mammal Research Unit, Institute for the Oceans and Fisheries,
University of British Columbia, Vancouver V6T 1Z4, Canada
| | - David Slip
- Marine Predator Research Group, Department of Biological Sciences,
Macquarie University, North Ryde 2113, Australia
- Taronga Conservation Society Australia, Mosman 2088, Australia
| | - Robert Harcourt
- Marine Predator Research Group, Department of Biological Sciences,
Macquarie University, North Ryde 2113, Australia
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17
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Kooyman GL, McDonald BI, Williams CL, Meir JU, Ponganis PJ. The aerobic dive limit: After 40 years, still rarely measured but commonly used. Comp Biochem Physiol A Mol Integr Physiol 2020; 252:110841. [PMID: 33186706 DOI: 10.1016/j.cbpa.2020.110841] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 11/04/2020] [Accepted: 11/04/2020] [Indexed: 11/15/2022]
Abstract
The aerobic dive limit (ADL) and the hypothesis that most dives are aerobic in nature have become fundamental to the understanding of diving physiology and to the interpretation of diving behavior and foraging ecology of marine mammals and seabirds. An ADL, the dive duration associated with the onset of post-dive blood lactate accumulation, has only been documented with blood lactate analyses in five species. Applications to other species have involved behavioral estimates or use of an oxygen store / metabolic rate formula. Both approaches have limitations, but have proved useful to the evaluation of the dive behavior and ecology of many species.
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Affiliation(s)
- Gerald L Kooyman
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093, USA
| | - Birgitte I McDonald
- Moss Landing Marine Laboratories, California State University, 8272 Moss Landing Road, Moss Landing, CA 95039, USA
| | - Cassondra L Williams
- National Marine Mammal Foundation, 2240 Shelter Island Drive, #200, San Diego, CA 92106, USA
| | | | - Paul J Ponganis
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093, USA.
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18
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19
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Environmental influences on foraging effort, success and efficiency in female Australian fur seals. Sci Rep 2020; 10:17710. [PMID: 33077806 PMCID: PMC7572486 DOI: 10.1038/s41598-020-73579-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 09/16/2020] [Indexed: 11/08/2022] Open
Abstract
Understanding the factors which influence foraging behaviour and success in marine mammals is crucial to predicting how their populations may respond to environmental change. The Australian fur seal (Arctocephalus pusillus doriferus, AUFS) is a predominantly benthic forager on the shallow continental shelf of Bass Strait, and represents the greatest biomass of marine predators in south-eastern Australia. The south-east Australian region is experiencing rapid oceanic warming, predicted to lead to substantial alterations in prey diversity, distribution and abundance. In the present study, foraging effort and indices of foraging success and efficiency were investigated in 138 adult female AUFS (970 foraging trips) during the winters of 1998–2019. Large scale climate conditions had a strong influence on foraging effort, foraging success and efficiency. Foraging effort and foraging success were also strongly influenced by winter chlorophyll-a concentrations and sea-surface height anomalies in Bass Strait. The results suggest increasing foraging effort and decreasing foraging success and efficiency under anticipated environmental conditions, which may have population-level impacts.
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20
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Quick NJ, Cioffi WR, Shearer JM, Fahlman A, Read AJ. Extreme diving in mammals: first estimates of behavioural aerobic dive limits in Cuvier's beaked whales. J Exp Biol 2020; 223:223/18/jeb222109. [DOI: 10.1242/jeb.222109] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 07/13/2020] [Indexed: 01/08/2023]
Abstract
ABSTRACT
We analysed 3680 dives from 23 satellite-linked tags deployed on Cuvier's beaked whales to assess the relationship between long duration dives and inter-deep dive intervals and to estimate aerobic dive limit (ADL). The median duration of presumed foraging dives was 59 min and 5% of dives exceeded 77.7 min. We found no relationship between the longest 5% of dive durations and the following inter-deep dive interval nor any relationship with the ventilation period immediately prior to or following a long dive. We suggest that Cuvier's beaked whales have low metabolic rates, high oxygen storage capacities and a high acid-buffering capacity to deal with the by-products of both aerobic and anaerobic metabolism, which enables them to extend dive durations and exploit their bathypelagic foraging habitats.
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Affiliation(s)
- Nicola J. Quick
- Duke University Marine Laboratory, Marine Science and Conservation, Nicholas School of the Environment, Beaufort, NC 28516, USA
| | - William R. Cioffi
- Duke University Marine Laboratory, University Program in Ecology, Nicholas School of the Environment, Beaufort, NC 28516, USA
| | - Jeanne M. Shearer
- Duke University Marine Laboratory, University Program in Ecology, Nicholas School of the Environment, Beaufort, NC 28516, USA
| | - Andreas Fahlman
- Fundación Oceanogràfic de la Comunitat Valencia, Valencia, 46005, Spain
| | - Andrew J. Read
- Duke University Marine Laboratory, Marine Science and Conservation, Nicholas School of the Environment, Beaufort, NC 28516, USA
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21
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Noren SR. Postnatal development of diving physiology: implications of anthropogenic disturbance for immature marine mammals. ACTA ACUST UNITED AC 2020; 223:223/17/jeb227736. [PMID: 32917778 DOI: 10.1242/jeb.227736] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Marine mammals endure extended breath-holds while performing active behaviors, which has fascinated scientists for over a century. It is now known that these animals have large onboard oxygen stores and utilize oxygen-conserving mechanisms to prolong aerobically supported dives to great depths, while typically avoiding (or tolerating) hypoxia, hypercarbia, acidosis and decompression sickness (DCS). Over the last few decades, research has revealed that diving physiology is underdeveloped at birth. Here, I review the postnatal development of the body's oxygen stores, cardiorespiratory system and other attributes of diving physiology for pinnipeds and cetaceans to assess how physiological immaturity makes young marine mammals vulnerable to disturbance. Generally, the duration required for body oxygen stores to mature varies across species in accordance with the maternal dependency period, which can be over 2 years long in some species. However, some Arctic and deep-diving species achieve mature oxygen stores comparatively early in life (prior to weaning). Accelerated development in these species supports survival during prolonged hypoxic periods when calves accompany their mothers under sea ice and to the bathypelagic zone, respectively. Studies on oxygen utilization patterns and heart rates while diving are limited, but the data indicate that immature marine mammals have a limited capacity to regulate heart rate (and hence oxygen utilization) during breath-hold. Underdeveloped diving physiology, in combination with small body size, limits diving and swimming performance. This makes immature marine mammals particularly vulnerable to mortality during periods of food limitation, habitat alterations associated with global climate change, fishery interactions and other anthropogenic disturbances, such as exposure to sonar.
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Affiliation(s)
- Shawn R Noren
- Institute of Marine Science, University of California, Santa Cruz, CA 95060, USA
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22
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Sarmiento-Devia R, Sepúlveda M, Pavez G, Valdés J, Canto A, Orellana M, Oliva D. Diet composition of an opportunistic predator from an upwelling area in the Southeastern Pacific. AUSTRAL ECOL 2020. [DOI: 10.1111/aec.12944] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Ricardo Sarmiento-Devia
- Escuela de Biología Marina; Universidad del Sinú - Seccional Cartagena; Cartagena de Indias Colombia
| | - Maritza Sepúlveda
- Instituto de Biología; Facultad de Ciencias; Universidad de Valparaíso; Gran Bretaña 1111, Playa Ancha Valparaíso Chile
- Facultad de Ciencias; Centro de Investigación y Gestión de Recursos Naturales (CIGREN); Universidad de Valparaíso; Valparaíso Chile
- Núcleo Milenio INVASAL; Concepción Chile
| | - Guido Pavez
- Facultad de Ciencias; Centro de Investigación y Gestión de Recursos Naturales (CIGREN); Universidad de Valparaíso; Valparaíso Chile
- Núcleo Milenio INVASAL; Concepción Chile
- Departamento de Ciencias Ecológicas; Facultad de Ciencias; Universidad de Chile; Santiago Chile
| | - Jorge Valdés
- Instituto de Ciencias Naturales Alexander von Humboldt; Universidad de Antofagasta; Antofagasta Chile
| | - Anahí Canto
- Facultad de Ciencias; Centro de Investigación y Gestión de Recursos Naturales (CIGREN); Universidad de Valparaíso; Valparaíso Chile
| | - Muriel Orellana
- Facultad de Ciencias; Centro de Investigación y Gestión de Recursos Naturales (CIGREN); Universidad de Valparaíso; Valparaíso Chile
| | - Doris Oliva
- Instituto de Biología; Facultad de Ciencias; Universidad de Valparaíso; Gran Bretaña 1111, Playa Ancha Valparaíso Chile
- Facultad de Ciencias; Centro de Investigación y Gestión de Recursos Naturales (CIGREN); Universidad de Valparaíso; Valparaíso Chile
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23
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Lidgard DC, Bowen WD, Iverson SJ. Sex-differences in fine-scale home-range use in an upper-trophic level marine predator. MOVEMENT ECOLOGY 2020; 8:11. [PMID: 32082578 PMCID: PMC7020581 DOI: 10.1186/s40462-020-0196-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 02/05/2020] [Indexed: 06/10/2023]
Abstract
BACKGROUND The distribution of prey in the ocean is spatially and temporally patchy. How predators respond to this prey patchiness may have consequences on their foraging success, and thus physical condition. The recent ability to record fine-scale movements of marine animals combined with novel home-range analyses that incorporate the dimension of time should permit a better understanding of how individuals utilise different regions of space and the consequences on their foraging success. METHODS Over a six-year study, we used T-LoCoH (Time-Local Convex Hull) home-range software to model archival GPS (Global Positioning System) data from 81 grey seals to investigate the fine-scale spatio-temporal use of space and the distribution of apparent foraging effort. Regions of home-ranges were classified according to the frequency of return visits (site fidelity) and duration of visits (intensity of use). Generalized linear mixed -effects models were used to test hypotheses on seasonal changes in foraging distribution and behaviour and the role of space-use and state on determining foraging success. RESULTS Male grey seals had larger home-ranges and core areas than females, and both sexes showed a contraction in home-range and core area in fall leading up to the breeding season compared with summer. Heavier individuals had smaller core areas than lighter ones, suggesting access to higher quality habitat might be limited to those individuals with greater foraging experience and competitive ability. The size of the home-range or core area was not an important predictor of the rate of mass gain. A fine-scale spatio-temporal analysis of habitat use within the home-range provided evidence of intra-annual site fidelity at presumed foraging locations, suggesting predictably in prey distribution. Neither sex nor season were useful predictors for classifying behaviour. Rather, individual identity explained much of the variation in fine-scale behaviour. CONCLUSIONS Understanding how upper-trophic level marine predators use space provides opportunities to explore the consequences of variation in foraging tactics and their success on fitness. Having knowledge of the drivers that shape this intraspecific variation can contribute toward predicting how these predators may respond to both natural and man-made environmental forcing.
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Affiliation(s)
- D. C. Lidgard
- Department of Biology, Dalhousie University, B3H 4J1, Halifax, Nova Scotia Canada
- Population Ecology Division, Bedford Institute of Oceanography, Department of Fisheries and Oceans, Dartmouth, Nova Scotia B2Y 4A2 Canada
| | - W. D. Bowen
- Population Ecology Division, Bedford Institute of Oceanography, Department of Fisheries and Oceans, Dartmouth, Nova Scotia B2Y 4A2 Canada
| | - S. J. Iverson
- Department of Biology, Dalhousie University, B3H 4J1, Halifax, Nova Scotia Canada
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24
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McHuron EA, Sterling JT, Costa DP, Goebel ME. Factors affecting energy expenditure in a declining fur seal population. CONSERVATION PHYSIOLOGY 2019; 7:coz103. [PMID: 31890212 PMCID: PMC6933311 DOI: 10.1093/conphys/coz103] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 10/11/2019] [Accepted: 11/08/2019] [Indexed: 06/10/2023]
Abstract
Quantifying metabolic rates and the factors that influence them is key to wildlife conservation efforts because anthropogenic activities and habitat alteration can disrupt energy balance, which is critical for reproduction and survival. We investigated the effect of diving behaviour, diet and season on field metabolic rates (FMR) and foraging success of lactating northern fur seals (Callorhinus ursinus) from the Pribilof Islands during a period of population decline. Variation in at-sea FMR was in part explained by season and trip duration, with values that ranged from 5.18 to 9.68 W kg-1 (n = 48). Fur seals experienced a 7.2% increase in at-sea FMR from summer to fall and a 1.9% decrease in at-sea FMR for each additional day spent at sea. There was no effect of foraging effort, dive depth or diet on at-sea FMR. Mass gains increased with trip duration and were greater in the fall compared with summer, but were unrelated to at-sea FMR, diving behaviour and diet. Seasonal increases in at-sea FMR may have been due to costs associated with the annual molt but did not appear to adversely impact the ability of females to gain mass on foraging trips. The overall high metabolic rates in conjunction with the lack of any diet-related effects on at-sea FMR suggests that northern fur seals may have reached a metabolic ceiling early in the population decline. This provides indirect evidence that food limitation may be contributing to the low pup growth rates observed in the Pribilof Islands, as a high metabolic overhead likely results in less available energy for lactation. The limited ability of female fur seals to cope with changes in prey availability through physiological mechanisms is particularly concerning given the recent and unprecedented environmental changes in the Bering Sea that are predicted to have ecosystem-level impacts.
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Affiliation(s)
- Elizabeth A McHuron
- Joint Institute for the Atmosphere and Ocean, University of Washington, 3737 Brooklyn Ave NE, Seattle, WA 98105, USA
| | - Jeremy T Sterling
- Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service – NOAA, 7600 Sand Point Way NE, Seattle, WA 98115, USA
| | - Daniel P Costa
- Department of Ecology and Evolution, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, USA
| | - Michael E Goebel
- Department of Ecology and Evolution, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, USA
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25
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McHuron EA, Schwarz LK, Costa DP, Mangel M. A state-dependent model for assessing the population consequences of disturbance on income-breeding mammals. Ecol Modell 2018. [DOI: 10.1016/j.ecolmodel.2018.07.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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McHuron EA, Peterson SH, Hückstädt LA, Melin SR, Harris JD, Costa DP. The energetic consequences of behavioral variation in a marine carnivore. Ecol Evol 2018; 8:4340-4351. [PMID: 29721302 PMCID: PMC5916299 DOI: 10.1002/ece3.3983] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 02/11/2018] [Indexed: 11/17/2022] Open
Abstract
Intraspecific variability in foraging behavior has been documented across a range of taxonomic groups, yet the energetic consequences of this variation are not well understood for many species. Understanding the effect of behavioral variation on energy expenditure and acquisition is particularly crucial for mammalian carnivores because they have high energy requirements that place considerable pressure on prey populations. To determine the influence of behavior on energy expenditure and balance, we combined simultaneous measurements of at‐sea field metabolic rate (FMR) and foraging behavior in a marine carnivore that exhibits intraspecific behavioral variation, the California sea lion (Zalophus californianus). Sea lions exhibited variability in at‐sea FMR, with some individuals expending energy at a maximum of twice the rate of others. This variation was in part attributable to differences in diving behavior that may have been reflective of diet; however, this was only true for sea lions using a foraging strategy consisting of epipelagic (<200 m within the water column) and benthic dives. In contrast, sea lions that used a deep‐diving foraging strategy all had similar values of at‐sea FMR that were unrelated to diving behavior. Energy intake did not differ between foraging strategies and was unrelated to energy expenditure. Our findings suggest that energy expenditure in California sea lions may be influenced by interactions between diet and oxygen conservation strategies. There were no apparent energetic trade‐offs between foraging strategies, although there was preliminary evidence that foraging strategies may differ in their variability in energy balance. The energetic consequences of behavioral variation may influence the reproductive success of female sea lions and result in differential impacts of individuals on prey populations. These findings highlight the importance of quantifying the relationships between energy expenditure and foraging behavior in other carnivores for studies addressing fundamental and applied physiological and ecological questions.
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Affiliation(s)
- Elizabeth A McHuron
- Department of Ecology & Evolutionary Biology University of California Santa Cruz Santa Cruz CA USA
| | - Sarah H Peterson
- Department of Ecology & Evolutionary Biology University of California Santa Cruz Santa Cruz CA USA.,Institute of Marine Sciences Long Marine Laboratory University of California Santa Cruz Santa Cruz CA USA
| | - Luis A Hückstädt
- Department of Ecology & Evolutionary Biology University of California Santa Cruz Santa Cruz CA USA
| | - Sharon R Melin
- Marine Mammal Laboratory Alaska Fisheries Science Center/NOAA Seattle WA USA
| | - Jeffrey D Harris
- Marine Mammal Laboratory Alaska Fisheries Science Center/NOAA Seattle WA USA
| | - Daniel P Costa
- Department of Ecology & Evolutionary Biology University of California Santa Cruz Santa Cruz CA USA
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27
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Nordøy ES, Lager AR, Schots PC. Seasonal changes in background levels of deuterium and oxygen-18 prove water drinking by harp seals, which affects the use of the doubly labelled water method. ACTA ACUST UNITED AC 2017; 220:4450-4455. [PMID: 28982968 DOI: 10.1242/jeb.161943] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 09/26/2017] [Indexed: 11/20/2022]
Abstract
The aim of this study was to monitor seasonal changes in stable isotopes of pool freshwater and harp seal (Phoca groenlandica) body water, and to study whether these potential seasonal changes might bias results obtained using the doubly labelled water (DLW) method when measuring energy expenditure in animals with access to freshwater. Seasonal changes in the background levels of deuterium and oxygen-18 in the body water of four captive harp seals and in the freshwater pool in which they were kept were measured over a time period of 1 year. The seals were offered daily amounts of capelin and kept under a seasonal photoperiod of 69°N. Large seasonal variations of deuterium and oxygen-18 in the pool water were measured, and the isotope abundance in the body water showed similar seasonal changes to the pool water. This shows that the seals were continuously equilibrating with the surrounding water as a result of significant daily water drinking. Variations in background levels of deuterium and oxygen-18 in freshwater sources may be due to seasonal changes in physical processes such as precipitation and evaporation that cause fractionation of isotopes. Rapid and abrupt changes in the background levels of deuterium and oxygen-18 may complicate calculation of energy expenditure by use of the DLW method. It is therefore strongly recommended that analysis of seasonal changes in background levels of isotopes is performed before the DLW method is applied on (free-ranging) animals, and to use a control group in order to correct for changes in background levels.
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Affiliation(s)
- Erling S Nordøy
- Department of Arctic and Marine Biology, UiT - The Arctic University of Norway, Breivika, NO-9037 Tromsø, Norway
| | - Anne R Lager
- UNN University Hospital of North Norway, Division of Internal Medicine, Post-box 101, NO-9038 Tromsø, Norway
| | - Pauke C Schots
- Norwegian College of Fishery Science, UiT - The Arctic University of Norway, Breivika, NO-9037 Tromsø, Norway
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28
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Páez-Rosas D, Villegas-Amtmann S, Costa D. Intraspecific variation in feeding strategies of Galapagos sea lions: A case of trophic specialization. PLoS One 2017; 12:e0185165. [PMID: 29059188 PMCID: PMC5653192 DOI: 10.1371/journal.pone.0185165] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 09/07/2017] [Indexed: 12/05/2022] Open
Abstract
The trophic behavior of marine predators varies according to the level of competition to which they are exposed. In general, populations that inhabit lower productivity systems face a strong intraspecific competition, which contributes to the development of different foraging strategies to maximize nutritional efficiency. Given the high trophic flexibility of Zalophus wollebaeki, this species is considered appropriate for the analysis of such behavior. Furthermore, this trophic flexibility has allowed them to persist in a seemingly marginal ecosystem. In this study, we used a comparative analysis of variables (diet and dive behavior) related to Z. wollebaeki trophic niche plasticity to better understand their foraging ecology, using techniques such scat analysis, satellite telemetry and complementarily an isotopic analysis. Scat analysis revealed intra-population variation in their diet, represented by prey from different environments (epipelagic and benthic). These results are supported by the animals’ locations at sea and diving profiles. Global Positioning System (GPS) and time-depth recorder (TDR) records showed the existence of two groups, with differing feeding areas and diving behavior. Also the δ15N values showed differences in the trophic level at which the species fed. These results constitute a relevant finding in the evolutionary behavior of the species, showing that Z. wollebaeki has developed a high degree of foraging flexibility, thus increasing its survival rate in an ecosystem that is highly demanding in terms of resource availability.
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Affiliation(s)
- Diego Páez-Rosas
- Universidad San Francisco de Quito (USFQ) and Galapagos Science Center, Galápagos, Ecuador
- Dirección Parque Nacional Galápagos, Unidad Técnica Operativa San Cristóbal, Galápagos, Ecuador
- * E-mail:
| | - Stella Villegas-Amtmann
- Department of Ecology and Evolutionary Biology, University of California at Santa Cruz, Santa Cruz, United States of America
| | - Daniel Costa
- Department of Ecology and Evolutionary Biology, University of California at Santa Cruz, Santa Cruz, United States of America
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Ladds MA, Rosen DAS, Slip DJ, Harcourt RG. Proxies of energy expenditure for marine mammals: an experimental test of "the time trap". Sci Rep 2017; 7:11815. [PMID: 28924150 PMCID: PMC5603582 DOI: 10.1038/s41598-017-11576-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 08/23/2017] [Indexed: 11/25/2022] Open
Abstract
Direct measures of energy expenditure are difficult to obtain in marine mammals, and accelerometry may be a useful proxy. Recently its utility has been questioned as some analyses derived their measure of activity level by calculating the sum of accelerometry-based values and then comparing this summation to summed (total) energy expenditure (the so-called “time trap”). To test this hypothesis, we measured oxygen consumption of captive fur seals and sea lions wearing accelerometers during submerged swimming and calculated total and rate of energy expenditure. We compared these values with two potential proxies of energy expenditure derived from accelerometry data: flipper strokes and dynamic body acceleration (DBA). Total number of strokes, total DBA, and submergence time all predicted total oxygen consumption \documentclass[12pt]{minimal}
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\begin{document}$$({\boldsymbol{sV}}{{\boldsymbol{O}}}_{{\boldsymbol{2}}}$$\end{document}(sVO2 ml kg−1). However, both total DBA and total number of strokes were correlated with submergence time. Neither stroke rate nor mean DBA could predict the rate of oxygen consumption (\documentclass[12pt]{minimal}
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\begin{document}$$s\mathop{{\boldsymbol{V}}}\limits^{{\boldsymbol{.}}}{{\boldsymbol{O}}}_{{\boldsymbol{2}}}$$\end{document}sV.O2 ml min−1 kg−1). The relationship of total DBA and total strokes with total oxygen consumption is apparently a result of introducing a constant (time) into both sides of the relationship. This experimental evidence supports the conclusion that proxies derived from accelerometers cannot estimate the energy expenditure of marine mammals.
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Affiliation(s)
- Monique A Ladds
- School of Mathematics and Statistics, Victoria University of Wellington, Wellington, 6012, New Zealand. .,Marine Predator Research Group, Department of Biological Sciences, Macquarie University, North Ryde, 2113, NSW, Australia.
| | - David A S Rosen
- Marine Mammal Research Unit, Institute for the Oceans and Fisheries, University of British Columbia, 2202 Main Mall, Vancouver, BC V6T 1Z4, Canada
| | - David J Slip
- Marine Predator Research Group, Department of Biological Sciences, Macquarie University, North Ryde, 2113, NSW, Australia.,Taronga Conservation Society Australia, Bradley's Head Road, Mosman, 2088, NSW, Australia
| | - Robert G Harcourt
- Marine Predator Research Group, Department of Biological Sciences, Macquarie University, North Ryde, 2113, NSW, Australia
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30
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Berry TE, Osterrieder SK, Murray DC, Coghlan ML, Richardson AJ, Grealy AK, Stat M, Bejder L, Bunce M. DNA metabarcoding for diet analysis and biodiversity: A case study using the endangered Australian sea lion ( Neophoca cinerea). Ecol Evol 2017; 7:5435-5453. [PMID: 28770080 PMCID: PMC5528208 DOI: 10.1002/ece3.3123] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 04/12/2017] [Accepted: 05/08/2017] [Indexed: 11/10/2022] Open
Abstract
The analysis of apex predator diet has the ability to deliver valuable insights into ecosystem health, and the potential impacts a predator might have on commercially relevant species. The Australian sea lion (Neophoca cinerea) is an endemic apex predator and one of the world's most endangered pinnipeds. Given that prey availability is vital to the survival of top predators, this study set out to understand what dietary information DNA metabarcoding could yield from 36 sea lion scats collected across 1,500 km of its distribution in southwest Western Australia. A combination of PCR assays were designed to target a variety of potential sea lion prey, including mammals, fish, crustaceans, cephalopods, and birds. Over 1.2 million metabarcodes identified six classes from three phyla, together representing over 80 taxa. The results confirm that the Australian sea lion is a wide-ranging opportunistic predator that consumes an array of mainly demersal fauna. Further, the important commercial species Sepioteuthis australis (southern calamari squid) and Panulirus cygnus (western rock lobster) were detected, but were present in <25% of samples. Some of the taxa identified, such as fish, sharks and rays, clarify previous knowledge of sea lion prey, and some, such as eel taxa and two gastropod species, represent new dietary insights. Even with modest sample sizes, a spatial analysis of taxa and operational taxonomic units found within the scat shows significant differences in diet between many of the sample locations and identifies the primary taxa that are driving this variance. This study provides new insights into the diet of this endangered predator and confirms the efficacy of DNA metabarcoding of scat as a noninvasive tool to more broadly define regional biodiversity.
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Affiliation(s)
- Tina E. Berry
- Trace and Environmental DNA (TrEnD) LaboratoryDepartment of Environment and AgricultureCurtin UniversityBentleyWAAustralia
| | | | - Dáithí C. Murray
- Trace and Environmental DNA (TrEnD) LaboratoryDepartment of Environment and AgricultureCurtin UniversityBentleyWAAustralia
| | - Megan L. Coghlan
- Trace and Environmental DNA (TrEnD) LaboratoryDepartment of Environment and AgricultureCurtin UniversityBentleyWAAustralia
| | | | - Alicia K. Grealy
- Trace and Environmental DNA (TrEnD) LaboratoryDepartment of Environment and AgricultureCurtin UniversityBentleyWAAustralia
| | - Michael Stat
- Trace and Environmental DNA (TrEnD) LaboratoryDepartment of Environment and AgricultureCurtin UniversityBentleyWAAustralia
| | - Lars Bejder
- Cetacean Research UnitMurdoch UniversityMurdochWAAustralia
| | - Michael Bunce
- Trace and Environmental DNA (TrEnD) LaboratoryDepartment of Environment and AgricultureCurtin UniversityBentleyWAAustralia
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31
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Ladds MA, Slip DJ, Harcourt RG. Intrinsic and extrinsic influences on standard metabolic rates of three species of Australian otariid. CONSERVATION PHYSIOLOGY 2017; 5:cow074. [PMID: 28852504 PMCID: PMC5570045 DOI: 10.1093/conphys/cow074] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 12/15/2016] [Accepted: 01/09/2017] [Indexed: 06/07/2023]
Abstract
The study of marine mammal energetics can shed light on how these animals might adapt to changing environments. Their physiological potential to adapt will be influenced by extrinsic factors, such as temperature, and by intrinsic factors, such as sex and reproduction. We measured the standard metabolic rate (SMR) of males and females of three Australian otariid species (two Australian fur seals, three New Zealand fur seals and seven Australian sea lions). Mean SMR ranged from 0.47 to 1.05 l O2 min-1, which when adjusted for mass was from 5.33 to 7.44 ml O2 min-1 kg-1. We found that Australian sea lion mass-specific SMR (sSMR; in millilitres of oxygen per minute per kilogram) varied little in response to time of year or moult, but was significantly influenced by sex and water temperature. Likewise, sSMR of Australian and New Zealand fur seals was also influenced by sex and water temperature, but also by time of year (pre-moult, moult or post-moult). During the moult, fur seals had significantly higher sSMR than at other times of the year, whereas there was no discernible effect of moult for sea lions. For both groups, females had higher sSMR than males, but sea lions and fur seals showed different responses to changes in water temperature. The sSMR of fur seals increased with increasing water temperature, whereas sSMR of sea lions decreased with increasing water temperature. There were no species differences when comparing animals of the same sex. Our study suggests that fur seals have more flexibility in their physiology than sea lions, perhaps implying that they will be more resilient in a changing environment.
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Affiliation(s)
- Monique A. Ladds
- Marine Predator Research Group, Department of Biological Sciences, Macquarie University, North Ryde, NSW 2113, Australia
| | - David J. Slip
- Marine Predator Research Group, Department of Biological Sciences, Macquarie University, North Ryde, NSW 2113, Australia
- Taronga Conservation Society Australia, Bradley's Head Road, Mosman, NSW 2088, Australia
| | - Robert G. Harcourt
- Marine Predator Research Group, Department of Biological Sciences, Macquarie University, North Ryde, NSW 2113, Australia
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32
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Mate BR, Irvine LM, Palacios DM. The development of an intermediate-duration tag to characterize the diving behavior of large whales. Ecol Evol 2016; 7:585-595. [PMID: 28116055 PMCID: PMC5243192 DOI: 10.1002/ece3.2649] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2016] [Revised: 11/09/2016] [Accepted: 11/14/2016] [Indexed: 11/11/2022] Open
Abstract
The development of high-resolution archival tag technologies has revolutionized our understanding of diving behavior in marine taxa such as sharks, turtles, and seals during their wide-ranging movements. However, similar applications for large whales have lagged behind due to the difficulty of keeping tags on the animals for extended periods of time. Here, we present a novel configuration of a transdermally attached biologging device called the Advanced Dive Behavior (ADB) tag. The ADB tag contains sensors that record hydrostatic pressure, three-axis accelerometers, magnetometers, water temperature, and light level, all sampled at 1 Hz. The ADB tag also collects Fastloc GPS locations and can send dive summary data through Service Argos, while staying attached to a whale for typical periods of 3-7 weeks before releasing for recovery and subsequent data download. ADB tags were deployed on sperm whales (Physeter macrocephalus; N = 46), blue whales (Balaenoptera musculus; N = 8), and fin whales (B. physalus; N = 5) from 2007 to 2015, resulting in attachment durations from 0 to 49.6 days, and recording 31 to 2,539 GPS locations and 27 to 2,918 dives per deployment. Archived dive profiles matched well with published dive shapes of each species from short-term records. For blue and fin whales, feeding lunges were detected using peaks in accelerometer data and matched corresponding vertical excursions in the depth record. In sperm whales, rapid orientation changes in the accelerometer data, often during the bottom phase of dives, were likely related to prey pursuit, representing a relative measure of foraging effort. Sperm whales were documented repeatedly diving to, and likely foraging along, the seafloor. Data from the temperature sensor described the vertical structure of the water column in all three species, extending from the surface to depths >1,600 m. In addition to providing information needed to construct multiweek time budgets, the ADB tag is well suited to studying the effects of anthropogenic sound on whales by allowing for pre- and post-exposure monitoring of the whale's dive behavior. This tag begins to bridge the gap between existing long-duration but low-data throughput tags, and short-duration, high-resolution data loggers.
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Affiliation(s)
- Bruce R Mate
- Marine Mammal Institute and Department of Fisheries and Wildlife Oregon State University Newport OR USA
| | - Ladd M Irvine
- Marine Mammal Institute and Department of Fisheries and Wildlife Oregon State University Newport OR USA
| | - Daniel M Palacios
- Marine Mammal Institute and Department of Fisheries and Wildlife Oregon State University Newport OR USA
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33
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Ladds MA, Slip DJ, Harcourt RG. Swimming metabolic rates vary by sex and development stage, but not by species, in three species of Australian otariid seals. J Comp Physiol B 2016; 187:503-516. [PMID: 27803974 DOI: 10.1007/s00360-016-1046-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 10/12/2016] [Accepted: 10/20/2016] [Indexed: 11/28/2022]
Abstract
Physiology may limit the ability for marine mammals to adapt to changing environments. Depth and duration of foraging dives are a function of total available oxygen stores, which theoretically increase as animals grow, and metabolic costs. To evaluate how physiology may influence the travelling costs for seals to foraging patches in the wild, we measured metabolic rates of a cross-section of New Zealand fur seals, Australian fur seals and Australian sea lions representing different foraging strategies, development stages, sexes and sizes. We report values for standard metabolic rate, active metabolic rate (obtained from submerged swimming), along with estimates of cost of transport (COT), measured via respirometry. We found a decline in mass-specific metabolic rate with increased duration of submerged swimming. For most seals mass-specific metabolic rate increased with speed and for all seals mass-specific COT decreased with speed. Mass-specific metabolic rate was higher for subadult than adult fur seals and sea lions, corresponding to an overall higher minimum COT. Some sex differences were also apparent, such that female Australian fur seals and Australian sea lions had higher mass-specific metabolic rates than males. There were no species differences in standard or active metabolic rates for adult males or females. The seals in our study appear to operate at their physiological optimum during submerged swimming. However, the higher metabolic rates of young and female fur seals and sea lions may limit their scope for increasing foraging effort during times of resource limitation.
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Affiliation(s)
- Monique A Ladds
- Marine Predator Research Group, Department of Biological Sciences, Macquarie University, North Ryde, NSW, 2113, Australia.
| | - David J Slip
- Marine Predator Research Group, Department of Biological Sciences, Macquarie University, North Ryde, NSW, 2113, Australia.,Taronga Conservation Society Australia, Bradley's Head Road, Mosman, NSW, 2088, Australia
| | - Robert G Harcourt
- Marine Predator Research Group, Department of Biological Sciences, Macquarie University, North Ryde, NSW, 2113, Australia
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34
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Cook PF, Reichmuth C, Rouse A, Dennison S, Van Bonn B, Gulland F. Natural exposure to domoic acid causes behavioral perseveration in Wild Sea lions: Neural underpinnings and diagnostic application. Neurotoxicol Teratol 2016; 57:95-105. [DOI: 10.1016/j.ntt.2016.08.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Revised: 08/04/2016] [Accepted: 08/05/2016] [Indexed: 01/27/2023]
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35
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Ware C, Trites AW, Rosen DAS, Potvin J. Averaged Propulsive Body Acceleration (APBA) Can Be Calculated from Biologging Tags That Incorporate Gyroscopes and Accelerometers to Estimate Swimming Speed, Hydrodynamic Drag and Energy Expenditure for Steller Sea Lions. PLoS One 2016; 11:e0157326. [PMID: 27285467 PMCID: PMC4902303 DOI: 10.1371/journal.pone.0157326] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 05/27/2016] [Indexed: 11/19/2022] Open
Abstract
Forces due to propulsion should approximate forces due to hydrodynamic drag for animals horizontally swimming at a constant speed with negligible buoyancy forces. Propulsive forces should also correlate with energy expenditures associated with locomotion-an important cost of foraging. As such, biologging tags containing accelerometers are being used to generate proxies for animal energy expenditures despite being unable to distinguish rotational movements from linear movements. However, recent miniaturizations of gyroscopes offer the possibility of resolving this shortcoming and obtaining better estimates of body accelerations of swimming animals. We derived accelerations using gyroscope data for swimming Steller sea lions (Eumetopias jubatus), and determined how well the measured accelerations correlated with actual swimming speeds and with theoretical drag. We also compared dive averaged dynamic body acceleration estimates that incorporate gyroscope data, with the widely used Overall Dynamic Body Acceleration (ODBA) metric, which does not use gyroscope data. Four Steller sea lions equipped with biologging tags were trained to swim alongside a boat cruising at steady speeds in the range of 4 to 10 kph. At each speed, and for each dive, we computed a measure called Gyro-Informed Dynamic Acceleration (GIDA) using a method incorporating gyroscope data with accelerometer data. We derived a new metric-Averaged Propulsive Body Acceleration (APBA), which is the average gain in speed per flipper stroke divided by mean stroke cycle duration. Our results show that the gyro-based measure (APBA) is a better predictor of speed than ODBA. We also found that APBA can estimate average thrust production during a single stroke-glide cycle, and can be used to estimate energy expended during swimming. The gyroscope-derived methods we describe should be generally applicable in swimming animals where propulsive accelerations can be clearly identified in the signal-and they should also prove useful for dead-reckoning and improving estimates of energy expenditures from locomotion.
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Affiliation(s)
- Colin Ware
- Center for Coastal and Ocean Mapping, University of New Hampshire, Durham, New Hampshire, United States of America
| | - Andrew W. Trites
- Marine Mammal Research Unit, Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, British Columbia, Canada
| | - David A. S. Rosen
- Marine Mammal Research Unit, Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jean Potvin
- Department of Physics, Saint Louis University, St. Louis, Missouri, United States of America
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36
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Elliott KH. Measurement of flying and diving metabolic rate in wild animals: Review and recommendations. Comp Biochem Physiol A Mol Integr Physiol 2016; 202:63-77. [PMID: 27264988 DOI: 10.1016/j.cbpa.2016.05.025] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 05/16/2016] [Accepted: 05/27/2016] [Indexed: 10/21/2022]
Abstract
Animals' abilities to fly long distances and dive to profound depths fascinate earthbound researchers. Due to the difficulty of making direct measurements during flying and diving, many researchers resort to modeling so as to estimate metabolic rate during each of those activities in the wild, but those models can be inaccurate. Fortunately, the miniaturization, customization and commercialization of biologgers has allowed researchers to increasingly follow animals on their journeys, unravel some of their mysteries and test the accuracy of biomechanical models. I provide a review of the measurement of flying and diving metabolic rate in the wild, paying particular attention to mass loss, doubly-labelled water, heart rate and accelerometry. Biologgers can impact animal behavior and influence the very measurements they are designed to make, and I provide seven guidelines for the ethical use of biologgers. If biologgers are properly applied, quantification of metabolic rate across a range of species could produce robust allometric relationships that could then be generally applied. As measuring flying and diving metabolic rate in captivity is difficult, and often not directly translatable to field conditions, I suggest that applying multiple techniques in the field to reinforce one another may be a viable alternative. The coupling of multi-sensor biologgers with biomechanical modeling promises to improve precision in the measurement of flying and diving metabolic rate in wild animals.
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Affiliation(s)
- Kyle H Elliott
- Department of Natural Resource Sciences, McGill University, Ste Anne-de-Bellevue, QC, Canada
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37
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Hückstädt LA, Tift MS, Riet-Sapriza F, Franco-Trecu V, Baylis AMM, Orben RA, Arnould JPY, Sepulveda M, Santos-Carvallo M, Burns JM, Costa DP. Regional variability in diving physiology and behavior in a widely distributed air-breathing marine predator, the South American sea lion (Otaria byronia). ACTA ACUST UNITED AC 2016; 219:2320-30. [PMID: 27247316 DOI: 10.1242/jeb.138677] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 05/17/2016] [Indexed: 11/20/2022]
Abstract
Our understanding of how air-breathing marine predators cope with environmental variability is limited by our inadequate knowledge of their ecological and physiological parameters. Because of their wide distribution along both coasts of the sub-continent, South American sea lions (Otaria byronia) provide a valuable opportunity to study the behavioral and physiological plasticity of a marine predator in different environments. We measured the oxygen stores and diving behavior of South American sea lions throughout most of its range, allowing us to demonstrate that diving ability and behavior vary across its range. We found no significant differences in mass-specific blood volumes of sea lions among field sites and a negative relationship between mass-specific oxygen storage and size, which suggests that exposure to different habitats and geographical locations better explains oxygen storage capacities and diving capability in South American sea lions than body size alone. The largest animals in our study (individuals from Uruguay) were the shallowest and shortest duration divers, and had the lowest mass-specific total body oxygen stores, while the deepest and longest duration divers (individuals from southern Chile) had significantly larger mass-specific oxygen stores, despite being much smaller animals. Our study suggests that the physiology of air-breathing diving predators is not fixed, but that it can be adjusted, to a certain extent, depending on the ecological setting and or habitat. These adjustments can be thought of as a 'training effect': as the animal continues to push its physiological capacity through greater hypoxic exposure, its breath-holding capacity increases.
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Affiliation(s)
- Luis A Hückstädt
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Long Marine Laboratory, 100 Shaffer Road, Santa Cruz, CA 95060, USA
| | - Michael S Tift
- Scripps Institution of Oceanography, University of California San Diego, Center for Marine Biodiversity and Biomedicine, 8655 Kennel Way, La Jolla, CA 92037, USA
| | - Federico Riet-Sapriza
- Laboratorio de Ecologia Molecular de Vertebrados Acuaticos (LEMVA), Departamento de Ciencias Biologicas, Facultad de Ciencias, Universidad de Los Andes, Carrera 1E, #18A-10, Bogota, Colombia
| | - Valentina Franco-Trecu
- Departamento de Ecología y Evolución Facultad de Ciencias, Universidad de la República, Iguá 4225 Esq. Mataojo C.P, 11400 Montevideo, Uruguay
| | - Alastair M M Baylis
- South Atlantic Environmental Research Institute, Stanley FIQQ1ZZ, Falkland Islands School of Life and Environmental Sciences, Deakin University, Warrnambool Campus, Geelong, Australia
| | - Rachael A Orben
- Hatfield Marine Science Center, Oregon State University, 2030 SE Marine Science Drive, Newport, OR 97365, USA
| | - John P Y Arnould
- School of Life and Environmental Sciences, Deakin University, Burwood Campus, Geelong, Australia
| | - Maritza Sepulveda
- Centro de Investigación y Gestión en Recursos Naturales (CIGREN), Instituto de Biología, Facultad de Ciencias, Universidad de Valparaíso, Avenida Gran Bretaña 1111, Playa Ancha, Valparaíso, Chile
| | - Macarena Santos-Carvallo
- Centro de Investigación y Gestión en Recursos Naturales (CIGREN), Instituto de Biología, Facultad de Ciencias, Universidad de Valparaíso, Avenida Gran Bretaña 1111, Playa Ancha, Valparaíso, Chile
| | - Jennifer M Burns
- Department of Biological Sciences, University of Alaska Anchorage. 3211 Providence Drive Anchorage, AK 99508, USA
| | - Daniel P Costa
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Long Marine Laboratory, 100 Shaffer Road, Santa Cruz, CA 95060, USA
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Foo D, Semmens JM, Arnould JP, Dorville N, Hoskins AJ, Abernathy K, Marshall GJ, Hindell MA. Testing optimal foraging theory models on benthic divers. Anim Behav 2016. [DOI: 10.1016/j.anbehav.2015.11.028] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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McHuron EA, Peterson SH, Ackerman JT, Melin SR, Harris JD, Costa DP. Effects of Age, Colony, and Sex on Mercury Concentrations in California Sea Lions. ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2016; 70:46-55. [PMID: 26259982 DOI: 10.1007/s00244-015-0201-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Accepted: 07/27/2015] [Indexed: 06/04/2023]
Abstract
We measured total mercury (THg) concentrations in California sea lions (Zalophus californianus) and examined how concentrations varied with age class, colony, and sex. Because Hg exposure is primarily via diet, we used nitrogen (δ (15)N) and carbon (δ (13)C) stable isotopes to determine if intraspecific differences in THg concentrations could be explained by feeding ecology. Blood and hair were collected from 21 adult females and 57 juveniles from three colonies in central and southern California (San Nicolas, San Miguel, and Año Nuevo Islands). Total Hg concentrations ranged from 0.01 to 0.31 μg g(-1) wet weight (ww) in blood and 0.74 to 21.00 μg g(-1) dry weight (dw) in hair. Adult females had greater mean THg concentrations than juveniles in blood (0.15 vs. 0.03 μg(-1) ww) and hair (10.10 vs. 3.25 μg(-1) dw). Age class differences in THg concentrations did not appear to be driven by trophic level or habitat type because there were no differences in δ (15)N or δ (13)C values between adults and juveniles. Total Hg concentrations in adult females were 54 % (blood) and 24 % (hair) greater in females from San Miguel than females from San Nicolas Island, which may have been because sea lions from the two islands foraged in different areas. For juveniles, we detected some differences in THg concentrations with colony and sex, although these were likely due to sampling effects and not ecological differences. Overall, THg concentrations in California sea lions were within the range documented for other marine mammals and were generally below toxicity benchmarks for fish-eating wildlife.
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Affiliation(s)
- Elizabeth A McHuron
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, 100 Shaffer Road, Santa Cruz, CA, 95060, USA.
| | - Sarah H Peterson
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, 100 Shaffer Road, Santa Cruz, CA, 95060, USA
| | - Joshua T Ackerman
- U.S. Geological Survey, Western Ecological Research Center, 800 Business Park Drive, Suite D, Dixon, CA, 95620, USA
| | - Sharon R Melin
- National Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 7600 Sand Point Way NE, Seattle, WA, 98155, USA
| | - Jeffrey D Harris
- National Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 7600 Sand Point Way NE, Seattle, WA, 98155, USA
| | - Daniel P Costa
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, 100 Shaffer Road, Santa Cruz, CA, 95060, USA
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Osterrieder SK, Salgado Kent C, Robinson RW. Variability in haul-out behaviour by male Australian sea lions Neophoca cinerea in the Perth metropolitan area, Western Australia. ENDANGER SPECIES RES 2015. [DOI: 10.3354/esr00690] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Kappes MA, Shaffer SA, Tremblay Y, Foley DG, Palacios DM, Bograd SJ, Costa DP. Reproductive constraints influence habitat accessibility, segregation, and preference of sympatric albatross species. MOVEMENT ECOLOGY 2015; 3:34. [PMID: 26421151 PMCID: PMC4587674 DOI: 10.1186/s40462-015-0063-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 09/09/2015] [Indexed: 05/27/2023]
Abstract
BACKGROUND The spatiotemporal distribution of animals is dependent on a suite of factors, including the distribution of resources, interactions within and between species, physiological limitations, and requirements for reproduction, dispersal, or migration. During breeding, reproductive constraints play a major role in the distribution and behavior of central place foragers, such as pelagic seabirds. We examined the foraging behavior and marine habitat selection of Laysan (Phoebastria immutabilis) and black-footed (P. nigripes) albatrosses throughout their eight month breeding cycle at Tern Island, Northwest Hawaiian Islands to evaluate how variable constraints of breeding influenced habitat availability and foraging decisions. We used satellite tracking and light-based geolocation to determine foraging locations of individuals, and applied a biologically realistic null usage model to generate control locations and model habitat preference under a case-control design. Remotely sensed oceanographic data were used to characterize albatross habitats in the North Pacific. RESULTS Individuals of both species ranged significantly farther and for longer durations during incubation and chick-rearing compared to the brooding period. Interspecific segregation of core foraging areas was observed during incubation and chick-rearing, but not during brooding. At-sea activity patterns were most similar between species during brooding; neither species altered foraging effort to compensate for presumed low prey availability and high energy demands during this stage. Habitat selection during long-ranging movements was most strongly associated with sea surface temperature for both species, with a preference for cooler ocean temperatures compared to overall availability. During brooding, lower explanatory power of habitat models was likely related to the narrow range of ocean temperatures available for selection. CONCLUSIONS Laysan and black-footed albatrosses differ from other albatross species in that they breed in an oligotrophic marine environment. During incubation and chick-rearing, they travel to cooler, more productive waters, but are restricted to the low-productivity environment near the colony during brooding, when energy requirements are greatest. Compared to other albatross species, Laysan and black-footed albatrosses spend a greater proportion of time in flight when foraging, especially during the brooding period; this strategy may be adaptive for locating dispersed prey in an oligotrophic environment.
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Affiliation(s)
- Michelle A. Kappes
- />Department of Ecology and Evolutionary Biology, University of California Santa Cruz, 100 Shaffer Road, Santa Cruz, California 95060 USA
- />Present address: Department of Fisheries and Wildlife, Oregon State University, 104 Nash Hall, Corvallis, Oregon 97331 USA
| | - Scott A. Shaffer
- />Department of Ecology and Evolutionary Biology, University of California Santa Cruz, 100 Shaffer Road, Santa Cruz, California 95060 USA
- />Present address: Department of Biological Sciences, San Jose State University, One Washington Square, San Jose, California 95192 USA
| | - Yann Tremblay
- />Department of Ecology and Evolutionary Biology, University of California Santa Cruz, 100 Shaffer Road, Santa Cruz, California 95060 USA
- />Present address: Institut pour la Recherche et le Développement, UMR 212 IRD-IFREMER-UM2. Av Jean Monnet 34200, Sète, France
| | - David G. Foley
- />Environmental Research Division, Southwest Fisheries Science Center, NOAA Fisheries, 1352 Lighthouse Avenue, Pacific Grove, California 93950 USA
- />Joint Institute for Marine and Atmospheric Research, University of Hawai’i at Manoa, 1000 Pope Road, Honolulu, Hawai’i 96822 USA
| | - Daniel M. Palacios
- />Environmental Research Division, Southwest Fisheries Science Center, NOAA Fisheries, 1352 Lighthouse Avenue, Pacific Grove, California 93950 USA
- />Joint Institute for Marine and Atmospheric Research, University of Hawai’i at Manoa, 1000 Pope Road, Honolulu, Hawai’i 96822 USA
| | - Steven J. Bograd
- />Environmental Research Division, Southwest Fisheries Science Center, NOAA Fisheries, 1352 Lighthouse Avenue, Pacific Grove, California 93950 USA
| | - Daniel P. Costa
- />Department of Ecology and Evolutionary Biology, University of California Santa Cruz, 100 Shaffer Road, Santa Cruz, California 95060 USA
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Adachi T, Maresh JL, Robinson PW, Peterson SH, Costa DP, Naito Y, Watanabe YY, Takahashi A. The foraging benefits of being fat in a highly migratory marine mammal. Proc Biol Sci 2015; 281:rspb.2014.2120. [PMID: 25377461 DOI: 10.1098/rspb.2014.2120] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Foraging theory predicts that breath-hold divers adjust the time spent foraging at depth relative to the energetic cost of swimming, which varies with buoyancy (body density). However, the buoyancy of diving animals varies as a function of their body condition, and the effects of these changes on swimming costs and foraging behaviour have been poorly examined. A novel animal-borne accelerometer was developed that recorded the number of flipper strokes, which allowed us to monitor the number of strokes per metre swam (hereafter, referred to as strokes-per-metre) by female northern elephant seals over their months-long, oceanic foraging migrations. As negatively buoyant seals increased their fat stores and buoyancy, the strokes-per-metre increased slightly in the buoyancy-aided direction (descending), but decreased significantly in the buoyancy-hindered direction (ascending), with associated changes in swim speed and gliding duration. Overall, the round-trip strokes-per-metre decreased and reached a minimum value when seals achieved neutral buoyancy. Consistent with foraging theory, seals stayed longer at foraging depths when their round-trip strokes-per-metre was less. Therefore, neutrally buoyant divers gained an energetic advantage via reduced swimming costs, which resulted in an increase in time spent foraging at depth, suggesting a foraging benefit of being fat.
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Affiliation(s)
- Taiki Adachi
- Department of Polar Science, The Graduate University for Advanced Studies (SOKENDAI), Tachikawa, Tokyo, Japan
| | - Jennifer L Maresh
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, USA
| | - Patrick W Robinson
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, USA
| | - Sarah H Peterson
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, USA
| | - Daniel P Costa
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, USA
| | - Yasuhiko Naito
- National Institute of Polar Research, Tachikawa, Tokyo, Japan
| | - Yuuki Y Watanabe
- Department of Polar Science, The Graduate University for Advanced Studies (SOKENDAI), Tachikawa, Tokyo, Japan National Institute of Polar Research, Tachikawa, Tokyo, Japan
| | - Akinori Takahashi
- Department of Polar Science, The Graduate University for Advanced Studies (SOKENDAI), Tachikawa, Tokyo, Japan National Institute of Polar Research, Tachikawa, Tokyo, Japan
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Volpov BL, Rosen DAS, Trites AW, Arnould JPY. Validating the relationship between 3-dimensional body acceleration and oxygen consumption in trained Steller sea lions. J Comp Physiol B 2015; 185:695-708. [PMID: 26002519 DOI: 10.1007/s00360-015-0911-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 05/01/2015] [Accepted: 05/08/2015] [Indexed: 11/27/2022]
Abstract
We tested the ability of overall dynamic body acceleration (ODBA) to predict the rate of oxygen consumption ([Formula: see text]) in freely diving Steller sea lions (Eumetopias jubatus) while resting at the surface and diving. The trained sea lions executed three dive types-single dives, bouts of multiple long dives with 4-6 dives per bout, or bouts of multiple short dives with 10-12 dives per bout-to depths of 40 m, resulting in a range of activity and oxygen consumption levels. Average metabolic rate (AMR) over the dive cycle or dive bout calculated was calculated from [Formula: see text]. We found that ODBA could statistically predict AMR when data from all dive types were combined, but that dive type was a significant model factor. However, there were no significant linear relationships between AMR and ODBA when data for each dive type were analyzed separately. The potential relationships between AMR and ODBA were not improved by including dive duration, food consumed, proportion of dive cycle spent submerged, or number of dives per bout. It is not clear whether the lack of predictive power within dive type was due to low statistical power, or whether it reflected a true absence of a relationship between ODBA and AMR. The average percent error for predicting AMR from ODBA was 7-11 %, and standard error of the estimated AMR was 5-32 %. Overall, the extensive range of dive behaviors and physiological conditions we tested indicated that ODBA was not suitable for estimating AMR in the field due to considerable error and the inconclusive effects of dive type.
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Affiliation(s)
- Beth L Volpov
- School of Life and Environmental Sciences, Deakin University, Burwood, VIC, 3125, Australia,
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44
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Sperm whale echolocation behaviour reveals a directed, prior-based search strategy informed by prey distribution. Behav Ecol Sociobiol 2015. [DOI: 10.1007/s00265-015-1877-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Bestley S, Jonsen ID, Hindell MA, Harcourt RG, Gales NJ. Taking animal tracking to new depths: synthesizing horizontal–vertical movement relationships for four marine predators. Ecology 2015; 96:417-27. [DOI: 10.1890/14-0469.1] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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46
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Evolutionary theory as a tool for predicting extinction risk. Trends Ecol Evol 2015; 30:61-5. [PMID: 25578283 DOI: 10.1016/j.tree.2014.12.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Revised: 12/01/2014] [Accepted: 12/03/2014] [Indexed: 01/17/2023]
Abstract
Timely and proactive wildlife conservation requires strategies for determining which species are most at the greatest threat of extinction. Here, we suggest that evolutionary theory, particularly the concept of specialization, can be a useful tool to inform such assessments and may greatly aid in our ability to predict the vulnerabilities of species to anthropogenic impacts.
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47
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Maresh JL, Simmons SE, Crocker DE, McDonald BI, Williams TM, Costa DP. Free-swimming northern elephant seals have low field metabolic rates that are sensitive to an increased cost of transport. ACTA ACUST UNITED AC 2015; 217:1485-95. [PMID: 24790099 DOI: 10.1242/jeb.094201] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Widely ranging marine predators often adopt stereotyped, energy-saving behaviours to minimize the energetic cost of transport while maximizing energy gain. Environmental and anthropogenic disturbances can disrupt energy balance by prompting avoidance behaviours that increase transport costs, thereby decreasing foraging efficiency. We examined the ability of 12 free-ranging, juvenile northern elephant seals (Mirounga angustirostris) to mitigate the effects of experimentally increased transport costs by modifying their behaviour and/or energy use in a compensatory manner. Under normal locomotion, elephant seals had low energy requirements (106.5±28.2 kJ kg(-1) day(-1)), approaching or even falling below predictions of basal requirements. Seals responded to a small increase in locomotion costs by spending more time resting between dives (149±44 s) compared with matched control treatments (102±11 s; P<0.01). Despite incurred costs, most other dive and transit behaviours were conserved across treatments, including fixed, rhythmic swimming gaits. Because of this, and because each flipper stroke had a predictable effect on total costs (P<0.001), total energy expenditure was strongly correlated with time spent at sea under both treatments (P<0.0001). These results suggest that transiting elephant seals have a limited capacity to modify their locomotory behaviour without increasing their transport costs. Based on this, we conclude that elephant seals and other ocean predators occupying similar niches may be particularly sensitive to increased transport costs incurred when avoiding unanticipated disturbances.
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Affiliation(s)
- Jennifer L Maresh
- Department of Ecology & Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
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48
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Noren SR, Jay CV, Burns JM, Fischbach AS. Rapid maturation of the muscle biochemistry that supports diving in pacific walruses (Odobenus rosmarus divergens). J Exp Biol 2015; 218:3319-29. [PMID: 26347559 DOI: 10.1242/jeb.125757] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 08/24/2015] [Indexed: 11/20/2022]
Abstract
Physiological constraints dictate animals' abilities to exploit habitats. For marine mammals, it is important to quantify physiological limits that influence diving and their ability to alter foraging behaviors. We characterized age-specific dive limits of walruses by measuring anaerobic (acid buffering capacity) and aerobic (myoglobin content) capacities of the muscles that power hind (longissimus dorsi) and fore (supraspinatus) flipper propulsion. Mean buffering capacities were similar across muscles and age classes (a fetus, 5 neonatal calves, a 3-month old, and 20 adults), ranging from 41.31 – 54.14 slykes and 42.00 – 46.93 slykes in the longissimus and supraspinatus, respectively. Mean myoglobin in the fetus and neonatal calves fell within a narrow range (longissimus: 0.92 – 1.68 g 100 g wet muscle mass−1; supraspinatus: 0.88 – 1.64 g wet muscle mass−1). By 3 months postpartum, myoglobin in the longissimus increased by 79%, but levels in the supraspinatus remained unaltered. From 3-months postpartum to adulthood, myoglobin increased by an additional 26% in the longissimus and increased by 126% in the supraspinatus; myoglobin remained greater in the longissimus compared to the supraspinatus. Walruses are unique among marine mammals because they are born with mature muscle acid buffering capacity and attain mature myoglobin content early in life. Despite rapid physiological development, small body size limits the diving capacity of immature walruses and extreme sexual dimorphism reduces the diving capacity of adult females compared to adult males. Thus, free-ranging immature walruses likely exhibit the shortest foraging dives while adult males are capable of the longest foraging dives.
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Affiliation(s)
- Shawn R. Noren
- Institute of Marine Science, University of California, Santa Cruz, Center for Ocean Health, 100 Shaffer Road, Santa Cruz, CA 95060, USA
| | - Chadwick V. Jay
- U.S. Geological Survey, Alaska Science Center, 4210 University Drive, Anchorage, AK 99508, USA
| | - Jennifer M. Burns
- University of Alaska, Anchorage, Department of Biological Sciences, CPSB 202C, 3101 Science Circle, University of Alaska, Anchorage, AK 99508, USA
| | - Anthony S. Fischbach
- U.S. Geological Survey, Alaska Science Center, 4210 University Drive, Anchorage, AK 99508, USA
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Lavery TJ, Roudnew B, Mitchell JG. Nitrogen transport from sea to land by a threatened and declining population of Australian sea lions (Neophoca cinerea) on Kangaroo Island, South Australia. AUSTRALIAN MAMMALOGY 2015. [DOI: 10.1071/am12029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Australian sea lions consume prey in highly productive foraging grounds and defaecate nutrients on land. The resident population of 1100 Australian sea lions contributes 3800 (±80) kg N year–1 into Seal Bay Conservation Park, Kangaroo Island, South Australia. If this population were to decline in abundance the nitrogen availability and coastal productivity of Kangaroo Island may be reduced.
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50
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Pacific walrus (Odobenus rosmarus divergens) resource selection in the Northern Bering Sea. PLoS One 2014; 9:e93035. [PMID: 24717979 PMCID: PMC3981674 DOI: 10.1371/journal.pone.0093035] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 02/28/2014] [Indexed: 11/19/2022] Open
Abstract
The Pacific walrus is a large benthivore with an annual range extending across the continental shelves of the Bering and Chukchi Seas. We used a discrete choice model to estimate site selection by adult radio-tagged walruses relative to the availability of the caloric biomass of benthic infauna and sea ice concentration in a prominent walrus wintering area in the northern Bering Sea (St. Lawrence Island polynya) in 2006, 2008, and 2009. At least 60% of the total caloric biomass of dominant macroinfauna in the study area was composed of members of the bivalve families Nuculidae, Tellinidae, and Nuculanidae. Model estimates indicated walrus site selection was related most strongly to tellinid bivalve caloric biomass distribution and that walruses selected lower ice concentrations from the mostly high ice concentrations that were available to them (quartiles: 76%, 93%, and 99%). Areas with high average predicted walrus site selection generally coincided with areas of high organic carbon input identified in other studies. Projected decreases in sea ice in the St. Lawrence Island polynya and the potential for a concomitant decline of bivalves in the region could result in a northward shift in the wintering grounds of walruses in the northern Bering Sea.
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