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Díaz MP, Kunc HP, Houghton JDR. Anthropogenic noise predicts sea turtle behavioural responses. MARINE POLLUTION BULLETIN 2024; 198:115907. [PMID: 38061147 DOI: 10.1016/j.marpolbul.2023.115907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 12/01/2023] [Accepted: 12/03/2023] [Indexed: 01/05/2024]
Abstract
Anthropogenic noise is a pollutant of global concern. While the effects of underwater noise pollution have been frequently studied in fish and mammals, our understanding of how this anthropogenic stressor affects marine reptiles is scant. Using a multichannel data logger equipped with a camera and hydrophone, we quantified behavioural responses of a free-ranging green turtle (Chelonia mydas) to vessel noise in the Galapagos Archipelago, an important nesting site in the eastern Pacific. We found that while travelling the turtle increased its vigilance with increasing vessel noise. However, when on the seabed the turtle did not increase its vigilance with increasing noise levels. Our findings illustrate that noise pollution has the potential to alter overall time budgets of animals. Identifying real-time responses of wild animals illustrate how in situ approaches allow to assess the effects of human activities on marine systems.
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Affiliation(s)
- Macarena Parra Díaz
- Charles Darwin Research Station, Charles Darwin Foundation, Puerto Ayora, Galapagos, Ecuador; School of Biological Sciences, Queen's University Belfast, 19 Chlorine Gardens, Co. Antrim BT9 5DL, UK
| | - Hansjoerg P Kunc
- School of Biological Sciences, Queen's University Belfast, 19 Chlorine Gardens, Co. Antrim BT9 5DL, UK.
| | - Jonathan D R Houghton
- School of Biological Sciences, Queen's University Belfast, 19 Chlorine Gardens, Co. Antrim BT9 5DL, UK; Queen's University Belfast Marine Laboratory, 12-13 The Strand, Portaferry, Co. Down BT22 1PF, UK
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2
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Smulders FOH, Bakker ES, O'Shea OR, Campbell JE, Rhoades OK, Christianen MJA. Green turtles shape the seascape through grazing patch formation around habitat features: Experimental evidence. Ecology 2023; 104:e3902. [PMID: 36310424 PMCID: PMC10078154 DOI: 10.1002/ecy.3902] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 08/10/2022] [Accepted: 09/07/2022] [Indexed: 02/03/2023]
Abstract
Understanding how megaherbivores incorporate habitat features into their foraging behavior is key toward understanding how herbivores shape the surrounding landscape. While the role of habitat structure has been studied within the context of predator-prey dynamics and grazing behavior in terrestrial systems, there is a limited understanding of how structure influences megaherbivore grazing in marine ecosystems. To investigate the response of megaherbivores (green turtles) to habitat features, we experimentally introduced structure at two spatial scales in a shallow seagrass meadow in The Bahamas. Turtle density increased 50-fold (to 311 turtles ha-1 ) in response to the structures, and turtles were mainly grazing and resting (low vigilance behavior). This resulted in a grazing patch exceeding the size of the experimental setup (242 m2 ), with reduced seagrass shoot density and aboveground biomass. After structure removal, turtle density decreased and vigilance increased (more browsing and shorter surfacing times), while seagrass within the patch partly recovered. Even at a small scale (9 m2 ), artificial structures altered turtle grazing behavior, resulting in grazing patches in 60% of the plots. Our results demonstrate that marine megaherbivores select habitat features as foraging sites, likely to be a predator refuge, resulting in heterogeneity in seagrass bed structure at the landscape scale.
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Affiliation(s)
- F O H Smulders
- Aquatic Ecology and Water Quality Management Group, Wageningen University & Research, Wageningen, The Netherlands
| | - E S Bakker
- Department of Aquatic Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands.,Wildlife Ecology and Conservation Group, Wageningen University, Wageningen, The Netherlands
| | - O R O'Shea
- The Centre for Ocean Research and Education (CORE), Gregory Town, The Bahamas
| | - J E Campbell
- Department of Biological Sciences, Institute of Environment, Florida International University, Miami, Florida, USA
| | - O K Rhoades
- Department of Biological Sciences, Institute of Environment, Florida International University, Miami, Florida, USA
| | - M J A Christianen
- Aquatic Ecology and Water Quality Management Group, Wageningen University & Research, Wageningen, The Netherlands
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3
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Hounslow JL, Fossette S, Byrnes EE, Whiting SD, Lambourne RN, Armstrong NJ, Tucker AD, Richardson AR, Gleiss AC. Multivariate analysis of biologging data reveals the environmental determinants of diving behaviour in a marine reptile. ROYAL SOCIETY OPEN SCIENCE 2022; 9:211860. [PMID: 35958091 PMCID: PMC9364005 DOI: 10.1098/rsos.211860] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 07/20/2022] [Indexed: 06/10/2023]
Abstract
Diving behaviour of 'surfacers' such as sea snakes, cetaceans and turtles is complex and multi-dimensional, thus may be better captured by multi-sensor biologging data. However, analysing these large multi-faceted datasets remains challenging, though a high priority. We used high-resolution multi-sensor biologging data to provide the first detailed description of the environmental influences on flatback turtle (Natator depressus) diving behaviour, during its foraging life-history stage. We developed an analytical method to investigate seasonal, diel and tidal effects on diving behaviour for 24 adult flatback turtles tagged with biologgers. We extracted 16 dive variables associated with three-dimensional and kinematic characteristics for 4128 dives. K-means and hierarchical cluster analyses failed to identify distinct dive types. Instead, principal component analysis objectively condensed the dive variables, removing collinearity and highlighting the main features of diving behaviour. Generalized additive mixed models of the main principal components identified significant seasonal, diel and tidal effects on flatback turtle diving behaviour. Flatback turtles altered their diving behaviour in response to extreme tidal and water temperature ranges, displaying thermoregulation and predator avoidance strategies while likely optimizing foraging in this challenging environment. This study demonstrates an alternative statistical technique for objectively interpreting diving behaviour from multivariate collinear data derived from biologgers.
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Affiliation(s)
- Jenna L. Hounslow
- Centre for Sustainable Aquatic Ecosystems, Harry Butler Institute, Murdoch University, Western Australia, Australia
- Environmental and Conservation Science, Murdoch University, Western Australia, Australia
| | - Sabrina Fossette
- Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions, Kensington, Western Australia, Australia
| | - Evan E. Byrnes
- Centre for Sustainable Aquatic Ecosystems, Harry Butler Institute, Murdoch University, Western Australia, Australia
- Environmental and Conservation Science, Murdoch University, Western Australia, Australia
- Faculty of Science, Simon Fraser University, British Columbia, Canada
| | - Scott D. Whiting
- Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions, Kensington, Western Australia, Australia
| | - Renae N. Lambourne
- Centre for Sustainable Aquatic Ecosystems, Harry Butler Institute, Murdoch University, Western Australia, Australia
- Environmental and Conservation Science, Murdoch University, Western Australia, Australia
| | - Nicola J. Armstrong
- School of Electrical Engineering, Computing and Mathematical Sciences, Curtin University, Bentley, Western Australia, Australia
| | - Anton D. Tucker
- Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions, Kensington, Western Australia, Australia
| | - Anthony R. Richardson
- Parks and Wildlife Service, West Kimberley District, Department of Biodiversity, Conservation and Attractions, Broome, Western Australia, Australia
| | - Adrian C. Gleiss
- Centre for Sustainable Aquatic Ecosystems, Harry Butler Institute, Murdoch University, Western Australia, Australia
- Environmental and Conservation Science, Murdoch University, Western Australia, Australia
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4
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Arce F, Hindell MA, McMahon CR, Wotherspoon SJ, Guinet C, Harcourt RG, Bestley S. Elephant seal foraging success is enhanced in Antarctic coastal polynyas. Proc Biol Sci 2022; 289:20212452. [PMID: 35078353 PMCID: PMC8790345 DOI: 10.1098/rspb.2021.2452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 12/02/2021] [Indexed: 01/28/2023] Open
Abstract
Antarctic polynyas are persistent open water areas which enable early and large seasonal phytoplankton blooms. This high primary productivity, boosted by iron supply from coastal glaciers, attracts organisms from all trophic levels to form a rich and diverse community. How the ecological benefit of polynya productivity is translated to the highest trophic levels remains poorly resolved. We studied 119 southern elephant seals feeding over the Antarctic shelf and demonstrated that: (i) 96% of seals foraging here used polynyas, with individuals spending on average 62% of their time there; (ii) the seals exhibited more area-restricted search behaviour when in polynyas; and (iii) these seals gained more energy (indicated by increased buoyancy from greater fat stores) when inside polynyas. This higher-quality foraging existed even when ice was not present in the study area, indicating that these are important and predictable foraging grounds year-round. Despite these energetic advantages from using polynyas, not all the seals used them extensively. Factors other than food supply may influence an individual's choice in their use of feeding grounds, such as exposure to predation or the probability of being able to return to distant sub-Antarctic breeding sites.
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Affiliation(s)
- Fernando Arce
- Institute for Marine and Antarctic Studies, University of Tasmania, Private Bag 129 Hobart, TAS 7001, Australia
- Australian Antarctic Division, 203 Channel Highway, Kingston, TAS 7050, Australia
| | - Mark A. Hindell
- Institute for Marine and Antarctic Studies, University of Tasmania, Private Bag 129 Hobart, TAS 7001, Australia
| | - Clive R. McMahon
- Institute for Marine and Antarctic Studies, University of Tasmania, Private Bag 129 Hobart, TAS 7001, Australia
- IMOS Animal Tagging, Sydney Institute of Marine Science, Mosman, NSW 2088, Australia
- Department of Biological Sciences, Macquarie University, North Ryde, NSW 2113, Australia
| | - Simon J. Wotherspoon
- Institute for Marine and Antarctic Studies, University of Tasmania, Private Bag 129 Hobart, TAS 7001, Australia
- Australian Antarctic Division, 203 Channel Highway, Kingston, TAS 7050, Australia
| | - Christophe Guinet
- Centre d'Etudes Biologiques de Chizé, CNRS, Villiers en Bois 79360, France
| | - Robert G. Harcourt
- Department of Biological Sciences, Macquarie University, North Ryde, NSW 2113, Australia
| | - Sophie Bestley
- Institute for Marine and Antarctic Studies, University of Tasmania, Private Bag 129 Hobart, TAS 7001, Australia
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5
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Braun CD, Arostegui MC, Thorrold SR, Papastamatiou YP, Gaube P, Fontes J, Afonso P. The Functional and Ecological Significance of Deep Diving by Large Marine Predators. ANNUAL REVIEW OF MARINE SCIENCE 2022; 14:129-159. [PMID: 34416123 DOI: 10.1146/annurev-marine-032521-103517] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Many large marine predators make excursions from surface waters to the deep ocean below 200 m. Moreover, the ability to access meso- and bathypelagic habitats has evolved independently across marine mammals, reptiles, birds, teleost fishes, and elasmobranchs. Theoretical and empirical evidence suggests a number of plausible functional hypotheses for deep-diving behavior. Developing ways to test among these hypotheses will, however, require new ways to quantify animal behavior and biophysical oceanographic processes at coherent spatiotemporal scales. Current knowledge gaps include quantifying ecological links between surface waters and mesopelagic habitats and the value of ecosystem services provided by biomass in the ocean twilight zone. Growing pressure for ocean twilight zone fisheries creates an urgent need to understand the importance of the deep pelagic ocean to large marine predators.
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Affiliation(s)
- Camrin D Braun
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA;
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, Washington 98195, USA
| | - Martin C Arostegui
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA;
- Air-Sea Interaction and Remote Sensing Department, Applied Physics Laboratory, University of Washington, Seattle, Washington 98105, USA
| | - Simon R Thorrold
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA;
| | - Yannis P Papastamatiou
- Institute of Environment, Department of Biological Sciences, Florida International University, Miami, Florida 33181, USA
| | - Peter Gaube
- Air-Sea Interaction and Remote Sensing Department, Applied Physics Laboratory, University of Washington, Seattle, Washington 98105, USA
| | - Jorge Fontes
- Okeanos and Institute of Marine Research, University of the Azores, 9901-862 Horta, Portugal
| | - Pedro Afonso
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA;
- Okeanos and Institute of Marine Research, University of the Azores, 9901-862 Horta, Portugal
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6
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Hall KE, James MC. Predation of satellite-tagged juvenile loggerhead turtles Caretta caretta in the Northwest Atlantic Ocean. ENDANGER SPECIES RES 2021. [DOI: 10.3354/esr01165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
We present evidence of predator interactions with 8 juvenile loggerhead sea turtles Caretta caretta equipped with pop-up satellite archival transmitting tags (PSATs) following incidental capture in the Northwest Atlantic. Ingestion of PSATs occurred up to 5 mo after tagging and was identified by an abrupt change in depth distribution, a stabilization and/or increase in ambient temperature and a marked drop in light levels to near zero, with cessation of diel light level cycling. In some cases, following expulsion from the digestive tract of predators, positively buoyant PSATs descended to the sea floor or beyond the programmed release depth threshold (1800 m), indicating that they remained tethered to the indigestible carapaces of turtles and that the entire turtle was originally consumed. PSAT data, combined with the sudden termination of satellite uplinks from 2 loggerheads also equipped with platform transmitting terminals, provided additional evidence of whole-turtle predation. PSAT data indicated that both endothermic and ectothermic sharks ingested tags. Based on PSAT-logged temperature data, dive patterns and geographic distribution, the following shark species were considered as candidate predators: white, porbeagle, shortfin mako, tiger and blue. This study represents the first analysis of data collected by loggerhead turtle PSATs inside predators. The results expand the list of shark species known to prey on large juvenile loggerheads and point to the importance of acknowledging predation as an important source of mortality for loggerhead turtles in the Northwest Atlantic Ocean.
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Affiliation(s)
- KE Hall
- Population Ecology Division, Fisheries and Oceans Canada, Bedford Institute of Oceanography, 1 Challenger Drive, Dartmouth, NS B2Y 4A2, Canada
| | - MC James
- Population Ecology Division, Fisheries and Oceans Canada, Bedford Institute of Oceanography, 1 Challenger Drive, Dartmouth, NS B2Y 4A2, Canada
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7
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Beltran RS, Kendall-Bar JM, Pirotta E, Adachi T, Naito Y, Takahashi A, Cremers J, Robinson PW, Crocker DE, Costa DP. Lightscapes of fear: How mesopredators balance starvation and predation in the open ocean. SCIENCE ADVANCES 2021; 7:7/12/eabd9818. [PMID: 33731347 PMCID: PMC7968837 DOI: 10.1126/sciadv.abd9818] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 01/27/2021] [Indexed: 05/06/2023]
Abstract
Like landscapes of fear, animals are hypothesized to strategically use lightscapes based on intrinsic motivations. However, longitudinal evidence of state-dependent risk aversion has been difficult to obtain in wild animals. Using high-resolution biologgers, we continuously measured body condition, time partitioning, three-dimensional movement, and risk exposure of 71 elephant seals throughout their 7-month foraging migrations (N = 16,000 seal days). As body condition improved from 21 to 32% fat and daylength declined from 16 to 10 hours, seals rested progressively earlier with respect to sunrise, sacrificing valuable nocturnal foraging hours to rest in the safety of darkness. Seals in superior body condition prioritized safety over energy conservation by resting >100 meters deeper where it was 300× darker. Together, these results provide empirical evidence that marine mammals actively use the three-dimensional lightscape to optimize risk-reward trade-offs based on ecological and physiological factors.
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Affiliation(s)
- Roxanne S Beltran
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, CA, USA.
| | - Jessica M Kendall-Bar
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - Enrico Pirotta
- Department of Mathematics and Statistics, Washington State University, Vancouver, WA, USA
- School of Biological, Earth and Environmental Sciences, University College Cork, Cork, Ireland
| | - Taiki Adachi
- School of Biology, University of St Andrews, St Andrews, Fife, Scotland, UK
| | - Yasuhiko Naito
- National Institute of Polar Research, Tachikawa, Tokyo, Japan
| | | | - Jolien Cremers
- Section of Biostatistics, Department of Public Health, University of Copenhagen, Copenhagen, Denmark
| | - Patrick W Robinson
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - Daniel E Crocker
- Department of Biology, Sonoma State University, Rohnert Park, CA, USA
| | - Daniel P Costa
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, CA, USA
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8
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Rodgers EM, Franklin CE, Noble DWA. Diving in hot water: a meta-analytic review of how diving vertebrate ectotherms will fare in a warmer world. J Exp Biol 2021; 224:224/Suppl_1/jeb228213. [PMID: 33627460 DOI: 10.1242/jeb.228213] [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] [Indexed: 01/23/2023]
Abstract
Diving ectothermic vertebrates are an important component of many aquatic ecosystems, but the threat of climate warming is particularly salient to this group. Dive durations typically decrease as water temperatures rise; yet, we lack an understanding of whether this trend is apparent in all diving ectotherms and how this group will fare under climate warming. We compiled data from 27 studies on 20 ectothermic vertebrate species to quantify the effect of temperature on dive durations. Using meta-analytic approaches, we show that, on average, dive durations decreased by 11% with every 1°C increase in water temperature. Larger increases in temperature (e.g. +3°C versus +8-9°C) exerted stronger effects on dive durations. Although species that respire bimodally are projected to be more resilient to the effects of temperature on dive durations than purely aerial breathers, we found no significant difference between these groups. Body mass had a weak impact on mean dive durations, with smaller divers being impacted by temperature more strongly. Few studies have examined thermal phenotypic plasticity (N=4) in diving ectotherms, and all report limited plasticity. Average water temperatures in marine and freshwater habitats are projected to increase between 1.5 and 4°C in the next century, and our data suggest that this magnitude of warming could translate to substantial decreases in dive durations, by approximately 16-44%. Together, these data shed light on an overlooked threat to diving ectothermic vertebrates and suggest that time available for underwater activities, such as predator avoidance and foraging, may be shortened under future warming.
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Affiliation(s)
- Essie M Rodgers
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT 2600, Australia
| | - Craig E Franklin
- School of Biological Sciences, The University of Queensland, St Lucia, 4072 Queensland, Australia
| | - Daniel W A Noble
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT 2600, Australia
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9
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Suzuki M, Anraku M, Hakamata W, Kishida T, Ueda K, Endoh T. Antioxidative Potency of Dolphin Serum Albumin Is Stronger Than That of Human Serum Albumin Irrespective of Substitution of 34Cysteine With Serine. Front Physiol 2020; 11:598451. [PMID: 33224041 PMCID: PMC7667151 DOI: 10.3389/fphys.2020.598451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 10/06/2020] [Indexed: 11/13/2022] Open
Abstract
Serum albumin (SA), the most abundant protein in circulation, functions as a carrier protein, osmoregulator, and antioxidant. Generally, SA exerts its antioxidative effects by scavenging reactive oxygen species. Because marine mammals are superior divers, they are intermittently exposed to oxidative stress induced by rapid reperfusion of oxygen to ischemic tissues after the dive. Although several antioxidants in marine mammals have been described, SA activity remains largely uncharacterized. In this study, we investigated the antioxidative activity of SA in marine mammals by comparing features of the primary and steric structures, biochemical properties, and antioxidative activities of common bottlenose dolphin SA (DSA) and human SA (HSA). Our results revealed that DSA lacked free cysteine at position 34 that is important for the antioxidative activity of HSA; however, the antioxidative capacity and thiol activity of DSA were stronger than those of HSA. Circular dichroism spectra showed different patterns in DSA and HSA. Ultraviolet fluorescence intensities of DSA were higher than those of HSA, suggesting lower surface hydrophobicity of DSA. Additionally, DSA showed higher excess heat capacity than HSA. We then compared a homology model of DSA with a 3D model of HSA. Our results indicate that DSA was more unstable than HSA at least in the body-temperature range, probably due to the mode of molecules involved in the disulfide bonds and/or the lower surface hydrophobicity, and it may be related to the equivalent or stronger antioxidant potency of DSA. These data show that DSA is an effective antioxidant in the circulation of the dolphin.
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Affiliation(s)
- Miwa Suzuki
- Laboratory of Aquatic Animal Physiology, Department of Marine Science and Resources, College of Bioresource Sciences, Nihon University, Fujisawa, Japan
| | - Makoto Anraku
- Laboratory of Physical Pharmaceutics, Faculty of Pharmaceutical Sciences, Sojo University, Kumamoto, Japan
| | - Wataru Hakamata
- Laboratory of Biological Chemistry, Department of Chemistry and Life Science, College of Bioresource Sciences, Nihon University, Fujisawa, Japan
| | - Takushi Kishida
- Wildlife Research Center, Kyoto University, Kyoto, Japan.,Museum of Natural and Environmental History, Shizuoka, Japan
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10
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Rodgers EM, Franklin CE. Diving beyond Aerobic Limits: Effect of Temperature on Anaerobic Support of Simulated Predator Avoidance Dives in an Air-Breathing Ectotherm. Physiol Biochem Zool 2019; 92:293-302. [PMID: 30864880 DOI: 10.1086/702828] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Diving optimality models predict air breathers to routinely dive within aerobic limits, but predator avoidance dives may be an exception. Lengthening submergence times during a predation threat may enhance survival probability, and we therefore hypothesized that predator avoidance dives in juvenile estuarine crocodiles (Crocodylus porosus) would be partially anaerobically fueled. We also predicted that reliance on anaerobic metabolism would increase at elevated temperatures to offset the faster depletion of body oxygen stores. Crocodiles were maintained at 28° and 34°C for 60 d and subsequently underwent simulated predator avoidance dive trials at two test temperatures (28° and 34°C). Blood was sampled immediately on surfacing to measure plasma lactate concentrations relative to nondiving (control) values. Aerobic dive limits (cADL; min) were also calculated using known body mass and oxygen storage relationships and rates of diving oxygen consumption and compared with observed dive durations. Postdive plasma lactate levels were elevated beyond resting levels at both test temperatures, indicating that aerobic thresholds were surpassed during simulated predator avoidance dives. Similarly, ≥90% of dive durations exceeded cADLs at both test temperatures. Postdive plasma lactate concentrations were independent of water temperature and thermal acclimation treatment. Together, these findings suggest that reliance on anaerobiosis during simulated predator avoidance dives is important regardless of temperature.
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11
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Dicken ML, Hussey NE, Christiansen HM, Smale MJ, Nkabi N, Cliff G, Wintner SP. Diet and trophic ecology of the tiger shark (Galeocerdo cuvier) from South African waters. PLoS One 2017; 12:e0177897. [PMID: 28594833 PMCID: PMC5464543 DOI: 10.1371/journal.pone.0177897] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 05/04/2017] [Indexed: 11/18/2022] Open
Abstract
Knowledge of the diet and trophic ecology of apex predators is key for the implementation of effective ecosystem as well as species-based management initiatives. Using a combination of stomach content data and stable isotope analysis (δ15N and δ13C) the current study provides information on size-based and sex-specific variations in diet, trophic position (TP) and foraging habitat of tiger sharks (Galeocerdo cuvier) caught in the KwaZulu-Natal Sharks Board bather protection program. This study presents the longest time-series and most detailed analysis of stomach content data for G. cuvier worldwide. Prey identified from 628 non-empty stomachs revealed a size-based shift in diet. Reptiles, birds, mysticetes, and large shark species increased in dietary importance with G. cuvier size, concomitant with a decrease in smaller prey such as batoids and teleosts. Seasonal and decadal shifts in diet driven primarily by changes in the importance of elasmobranchs and mammal (cetacean) prey were recorded for medium sized (150-220 cm) G. cuvier. Both stomach content and stable isotope analysis indicated that G. cuvier is a generalist feeder at the population level. Size-based δ13C profiles indicated a movement to offshore foraging habitats by larger G. cuvier. Calculated TP varied by method ranging from 4.0 to 5.0 (TPSCA for stomach contents) and from 3.6 to 4.5 (TPscaled and TPadditive for δ15N). Large (> 220 cm) G. cuvier did not feed at discrete trophic levels, but rather throughout the food web. These data provide key information on the ecological role of G. cuvier to improve the accuracy of regional food web modelling. This will enable a better understanding of the ecological impacts related to changes in the abundance of this predator.
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Affiliation(s)
- Matthew L. Dicken
- KwaZulu-Natal Sharks Board, Umhlanga Rocks, South Africa
- Department of Zoology and Entomology, University of Fort Hare, Alice. South Africa
- * E-mail:
| | - Nigel E. Hussey
- University of Windsor–Biological Sciences, Windsor, Ontario, Canada
| | | | - Malcolm J. Smale
- Department of Zoology, Nelson Mandela Metropolitan University, Port Elizabeth, South Africa
- Port Elizabeth Museum, Humewood, Port Elizabeth, South Africa
| | - Nomfundo Nkabi
- KwaZulu-Natal Sharks Board, Umhlanga Rocks, South Africa
| | - Geremy Cliff
- KwaZulu-Natal Sharks Board, Umhlanga Rocks, South Africa
- Biomedical Resource Unit, University of KwaZulu-Natal, Durban South Africa
| | - Sabine P. Wintner
- KwaZulu-Natal Sharks Board, Umhlanga Rocks, South Africa
- Biomedical Resource Unit, University of KwaZulu-Natal, Durban South Africa
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12
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Lyamin OI, Mukhametov LM, Siegel JM. Sleep in the northern fur seal. Curr Opin Neurobiol 2017; 44:144-151. [PMID: 28505502 PMCID: PMC5609733 DOI: 10.1016/j.conb.2017.04.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 04/20/2017] [Indexed: 11/17/2022]
Abstract
The pattern of sleep in the fur seal, a semiaquatic pinniped, has several striking behavioral and physiological adaptations that allow this species to inhabit both the land and water environment. These features include unihemispheric slow wave sleep (USWS, also being unihemispheric waking), the ability to maintain movement for stabilization of the sleep posture and to briefly open one eye while having a sleep electroencephalogram (EEG) in one hemisphere. In vivo microdialysis studies suggest that acetylcholine release is required for cortical activation during USWS, and that monoamines are not required for USWS. The need to breathe, to maintain efficient thermoregulation, and to avoid predation have shaped the sleep patterns in semiaquatic fur seals as in fully aquatic cetaceans.
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Affiliation(s)
- Oleg I Lyamin
- Department of Psychiatry and Biobehavioral Sciences, and Brain Research Institute, University of California Los Angeles, Los Angeles, CA, United States; Severtsov Institute of Ecology and Evolution, RAS, Moscow, Russia; Utrish Dolphinarium Ltd., Moscow, Russia
| | - Lev M Mukhametov
- Severtsov Institute of Ecology and Evolution, RAS, Moscow, Russia; Utrish Dolphinarium Ltd., Moscow, Russia
| | - Jerome M Siegel
- Department of Psychiatry and Biobehavioral Sciences, and Brain Research Institute, University of California Los Angeles, Los Angeles, CA, United States; Severtsov Institute of Ecology and Evolution, RAS, Moscow, Russia.
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Udyawer V, Simpfendorfer CA, Heupel MR, Clark TD. Temporal and spatial activity‐associated energy partitioning in free‐swimming sea snakes. Funct Ecol 2017. [DOI: 10.1111/1365-2435.12882] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Vinay Udyawer
- Australian Institute of Marine Science Townsville QLD4810 Australia
- Centre for Sustainable Tropical Fisheries and Aquaculture & College of Science and Engineering James Cook University Townsville QLD4811 Australia
| | - Colin A. Simpfendorfer
- Centre for Sustainable Tropical Fisheries and Aquaculture & College of Science and Engineering James Cook University Townsville QLD4811 Australia
| | - Michelle R. Heupel
- Australian Institute of Marine Science Townsville QLD4810 Australia
- Centre for Sustainable Tropical Fisheries and Aquaculture & College of Science and Engineering James Cook University Townsville QLD4811 Australia
| | - Timothy D. Clark
- Australian Institute of Marine Science Townsville QLD4810 Australia
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Hammerschlag N, Bell I, Fitzpatrick R, Gallagher AJ, Hawkes LA, Meekan MG, Stevens JD, Thums M, Witt MJ, Barnett A. Behavioral evidence suggests facultative scavenging by a marine apex predator during a food pulse. Behav Ecol Sociobiol 2016. [DOI: 10.1007/s00265-016-2183-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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15
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Udyawer V, Simpfendorfer CA, Heupel MR, Clark TD. Coming up for air: thermal-dependence of dive behaviours and metabolism in sea snakes. J Exp Biol 2016; 219:3447-3454. [DOI: 10.1242/jeb.146571] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 08/22/2016] [Indexed: 02/04/2023]
Abstract
Cutaneous gas exchange allows some air-breathing diving ectotherms to supplement their pulmonary oxygen uptake, which may allow prolongation of dives and an increased capacity to withstand anthropogenic and natural threatening processes that increase submergence times. However, little is known of the interplay between metabolism, bimodal oxygen uptake and activity levels across thermal environments in diving ectotherms. Here, we show in two species of sea snake (spine-bellied sea snake; Hydrophis curtus and elegant sea snake; H. elegans) that increasing temperature elevates surfacing rates, increases total oxygen consumption, and decreases dive durations. The majority of dives observed in both species remained within estimated maximal aerobic limits. While cutaneous gas exchange accounted for a substantial proportion of total oxygen consumption (up to 23%), unexpectedly it was independent of water temperature and activity levels, suggesting a diffusion-limited mechanism. Our findings demonstrate that rising water temperature and a limited capability to up-regulate cutaneous oxygen uptake may compromise the proficiency with which sea snakes perform prolonged dives. This may hinder their capacity to withstand ongoing anthropogenic activities like trawl fishing, and increase their susceptibility to surface predation as their natural environments continue to warm.
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Affiliation(s)
- Vinay Udyawer
- Centre for Sustainable Tropical Fisheries and Aquaculture & College of Marine and Environmental Sciences, James Cook University, Townsville, Queensland, Australia
| | - Colin A. Simpfendorfer
- Centre for Sustainable Tropical Fisheries and Aquaculture & College of Marine and Environmental Sciences, James Cook University, Townsville, Queensland, Australia
| | - Michelle R. Heupel
- Centre for Sustainable Tropical Fisheries and Aquaculture & College of Marine and Environmental Sciences, James Cook University, Townsville, Queensland, Australia
- Australian Institute of Marine Science, Townsville, Queensland, Australia
| | - Timothy D. Clark
- Australian Institute of Marine Science, Townsville, Queensland, Australia
- Current address: University of Tasmania & CSIRO Agriculture and Food, Hobart, Tasmania, Australia
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Goundie ET, Rosen DAS, Trites AW. Dive behaviour can predict metabolic expenditure in Steller sea lions. CONSERVATION PHYSIOLOGY 2015; 3:cov052. [PMID: 27293736 PMCID: PMC4778462 DOI: 10.1093/conphys/cov052] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 10/14/2015] [Accepted: 10/27/2015] [Indexed: 06/06/2023]
Abstract
Quantification of costs associated with foraging contributes to understanding the energetic impact that changes in prey availability have on the energy balance of an animal and the fitness of populations. However, estimating the costs of foraging is difficult for breath-hold divers, such as Steller sea lions, that feed underwater. We developed models parameterized with data from free-diving captive Steller sea lions to estimate the costs incurred by wild animals while foraging. We measured diving metabolic rate of trained sea lions performing four types of dives to 10 and 40 m in the open ocean and estimated the separate costs of different dive components: surface time; bottom time; and transiting to and from depth. We found that the sea lions' diving metabolic rates were higher while transiting (20.5 ± 13.0 ml O2 min(-1) kg(-1)) than while swimming at depth (13.5 ± 4.1 ml O2 min(-1) kg(-1)), and both were higher than metabolism at the surface (9.2 ± 1.6 ml O2 min(-1) kg(-1)). These values were incorporated into an energetic model that accurately predicted oxygen consumption for dives only (within 9.5%) and dive cycles (within 7.7%), although it consistently overestimated costs by 5.9% for dives and 21.8% for dive cycles. Differences in the costs of individual components of dives also explained differences in the efficiency of different dive strategies. Single dives were energetically less costly than bout dives; however, sea lions were more efficient at replenishing oxygen stores after bout dives and could therefore spend a greater portion of their time foraging than when undertaking single dives. The metabolic rates we measured for the different behavioural components of diving can be applied to time-depth recordings from wild Steller sea lions to estimate the energy expended while foraging. In turn, this can be used to understand how changes in prey availability affect energy balance and the health of individuals in declining populations.
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Affiliation(s)
- Elizabeth T Goundie
- Department of Zoology and Marine Mammal Research Unit, Institute for the Oceans and Fisheries, University of British Columbia, 2202 Main Mall, Vancouver, BC, Canada V6T 1Z4
| | - David A S Rosen
- Department of Zoology and Marine Mammal Research Unit, Institute for the Oceans and Fisheries, University of British Columbia, 2202 Main Mall, Vancouver, BC, Canada V6T 1Z4
| | - Andrew W Trites
- Department of Zoology and 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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Jouma'a J, Le Bras Y, Richard G, Vacquié‐Garcia J, Picard B, El Ksabi N, Guinet C. Adjustment of diving behaviour with prey encounters and body condition in a deep diving predator: the Southern Elephant Seal. Funct Ecol 2015. [DOI: 10.1111/1365-2435.12514] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
| | - Yves Le Bras
- CEBC UMR 7372 ULR‐CNRS 79360 Villiers en Bois France
| | | | | | | | - Nory El Ksabi
- CEBC UMR 7372 ULR‐CNRS 79360 Villiers en Bois France
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Hammerschlag N, Broderick AC, Coker JW, Coyne MS, Dodd M, Frick MG, Godfrey MH, Godley BJ, Griffin DB, Hartog K, Murphy SR, Murphy TM, Nelson ER, Williams KL, Witt MJ, Hawkes LA. Evaluating the landscape of fear between apex predatory sharks and mobile sea turtles across a large dynamic seascape. Ecology 2015; 96:2117-26. [DOI: 10.1890/14-2113.1] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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19
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Christiansen F, Lynas NM, Lusseau D, Tscherter U. Structure and dynamics of minke whale surfacing patterns in the Gulf of St. Lawrence, Canada. PLoS One 2015; 10:e0126396. [PMID: 25970425 PMCID: PMC4430536 DOI: 10.1371/journal.pone.0126396] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2014] [Accepted: 04/01/2015] [Indexed: 11/29/2022] Open
Abstract
Animal behavioral patterns can help us understand physiological and ecological constraints on animals and its influence on fitness. The surfacing patterns of aquatic air-breathing mammals constitute a behavioral pattern that has evolved as a trade-off between the need to replenish oxygen stores at the surface and the need to conduct other activities underwater. This study aims to better understand the surfacing pattern of a marine top predator, the minke whale (Balaenoptera acutorostrata), by investigating how their dive duration and surfacing pattern changes across their activity range. Activities were classified into resting, traveling, surface feeding and foraging at depth. For each activity, we classified dives into short and long dives and then estimated the temporal dependence between dive types. We found that minke whales modified their surfacing pattern in an activity-specific manner, both by changing the expression of their dives (i.e. density distribution) and the temporal dependence (transition probability) between dive types. As the depth of the prey layer increased between activities, the surfacing pattern of foraging whales became increasingly structured, going from a pattern dominated by long dives, when feeding at the surface, to a pattern where isolated long dives were followed by an increasing number of breaths (i.e. short dives), when the whale was foraging at depth. A similar shift in surfacing pattern occurred when prey handling time (inferred from surface corralling maneuvers) increased for surface feeding whales. The surfacing pattern also differed between feeding and non-feeding whales. Resting whales did not structure their surfacing pattern, while traveling whales did, possibly as a way to minimize cost of transport. Our results also suggest that minke whales might balance their oxygen level over multiple, rather than single, dive cycles.
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Affiliation(s)
- Fredrik Christiansen
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Warrnambool, Victoria, Australia
- Foundation for Marine Environment Research (ORES), Basel, Switzerland
| | - Ned M. Lynas
- Foundation for Marine Environment Research (ORES), Basel, Switzerland
- Ocean Research and Education Society (ORES), Les Bergeronnes, Quebec, Canada
| | - David Lusseau
- Institute of Biological and Environmental Sciences and Institute of Marine Alliance for Science and Technology for Scotland, University of Aberdeen, Aberdeen, United Kingdom
| | - Ursula Tscherter
- Foundation for Marine Environment Research (ORES), Basel, Switzerland
- Ocean Research and Education Society (ORES), Les Bergeronnes, Quebec, Canada
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Symons J, Pirotta E, Lusseau D. Sex differences in risk perception in deep-diving bottlenose dolphins leads to decreased foraging efficiency when exposed to human disturbance. J Appl Ecol 2014. [DOI: 10.1111/1365-2664.12337] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- John Symons
- Institute of Biological and Environmental Sciences; University of Aberdeen; Aberdeen AB24 2TZ UK
| | - Enrico Pirotta
- Institute of Biological and Environmental Sciences; University of Aberdeen; Aberdeen AB24 2TZ UK
| | - David Lusseau
- Institute of Biological and Environmental Sciences; University of Aberdeen; Aberdeen AB24 2TZ UK
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Activities, motivations and disturbance: An agent-based model of bottlenose dolphin behavioral dynamics and interactions with tourism in Doubtful Sound, New Zealand. Ecol Modell 2014. [DOI: 10.1016/j.ecolmodel.2014.03.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Heaslip SG, Bowen WD, Iverson SJ. Testing predictions of optimal diving theory using animal-borne video from harbour seals (Phoca vitulina concolor). CAN J ZOOL 2014. [DOI: 10.1139/cjz-2013-0137] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Optimal diving theory predicts that animals make decisions that maximize their foraging profitability subject to the constraint of oxygen stores. We examined the temporal pattern of prey encounters within a dive from concurrently collected dive data and animal-borne video from a free-ranging pinniped to test predictions of optimal diving theory. Crittercams were deployed on 32 adult male harbour seals (Phoca vitulina concolor De Kay, 1842) at Sable Island, Nova Scotia, Canada, for 3 days each. Deployments resulted in approximately 3 h of video per seal and a total of 2275 capture attempts for 1474 prey encounter events recorded. We found support for seven of the nine selected predictions of optimal diving theory. As predicted, prey encounters increased with bottom duration; dive duration increased with dive depth; and travel duration, bottom duration, and percent bottom duration decreased over a wide range of travel durations. Descent duration did increase with dive depth, and seals terminated dives earlier when no prey were encountered and when prey were encountered later in a dive. Contrary to prediction, bottom duration did not increase and then decrease for short travel durations and dives were not terminated earlier when travel durations were short and prey encounter rate was low.
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Affiliation(s)
- Susan G. Heaslip
- Dalhousie University, Life Sciences Centre, Department of Biology, 1355 Oxford Street, P.O. Box 15000, Halifax, NS B3H 4R2, Canada
| | - W. Don Bowen
- Dalhousie University, Life Sciences Centre, Department of Biology, 1355 Oxford Street, P.O. Box 15000, Halifax, NS B3H 4R2, Canada
- Fisheries and Oceans Canada, Bedford Institute of Oceanography, Population Ecology Division, 1 Challenger Drive, P.O. Box 1006, Dartmouth, NS B2Y 4A2, Canada
| | - Sara J. Iverson
- Dalhousie University, Life Sciences Centre, Department of Biology, 1355 Oxford Street, P.O. Box 15000, Halifax, NS B3H 4R2, Canada
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Somaweera R, Brien M, Shine R. The Role of Predation in Shaping Crocodilian Natural History. HERPETOLOGICAL MONOGRAPHS 2013. [DOI: 10.1655/herpmonographs-d-11-00001] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Ruchira Somaweera
- School of Biological Sciences, University of Sydney, Sydney, New Sout Wales 2006, Australia
| | - Matthew Brien
- Wildlife Management International Pty. Limited, Karama, Northern Territory 0813, Australia
| | - Richard Shine
- School of Biological Sciences, University of Sydney, Sydney, New Sout Wales 2006, Australia
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Robertson FC, Koski WR, Thomas TA, Richardson WJ, Würsig B, Trites AW. Seismic operations have variable effects on dive-cycle behavior of bowhead whales in the Beaufort Sea. ENDANGER SPECIES RES 2013. [DOI: 10.3354/esr00515] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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A comparison of the seasonal movements of tiger sharks and green turtles provides insight into their predator-prey relationship. PLoS One 2012; 7:e51927. [PMID: 23284819 PMCID: PMC3526478 DOI: 10.1371/journal.pone.0051927] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Accepted: 11/07/2012] [Indexed: 12/02/2022] Open
Abstract
During the reproductive season, sea turtles use a restricted area in the vicinity of their nesting beaches, making them vulnerable to predation. At Raine Island (Australia), the highest density green turtle Chelonia mydas rookery in the world, tiger sharks Galeocerdo cuvier have been observed to feed on green turtles, and it has been suggested that they may specialise on such air-breathing prey. However there is little information with which to examine this hypothesis. We compared the spatial and temporal components of movement behaviour of these two potentially interacting species in order to provide insight into the predator-prey relationship. Specifically, we tested the hypothesis that tiger shark movements are more concentrated at Raine Island during the green turtle nesting season than outside the turtle nesting season when turtles are not concentrated at Raine Island. Turtles showed area-restricted search behaviour around Raine Island for ∼3–4 months during the nesting period (November–February). This was followed by direct movement (transit) to putative foraging grounds mostly in the Torres Straight where they switched to area-restricted search mode again, and remained resident for the remainder of the deployment (53–304 days). In contrast, tiger sharks displayed high spatial and temporal variation in movement behaviour which was not closely linked to the movement behaviour of green turtles or recognised turtle foraging grounds. On average, tiger sharks were concentrated around Raine Island throughout the year. While information on diet is required to determine whether tiger sharks are turtle specialists our results support the hypothesis that they target this predictable and plentiful prey during turtle nesting season, but they might not focus on this less predictable food source outside the nesting season.
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Adaptations for marine habitat and the effect of Triassic and Jurassic predator pressure on development of decompression syndrome in ichthyosaurs. Naturwissenschaften 2012; 99:443-8. [PMID: 22573359 DOI: 10.1007/s00114-012-0918-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Revised: 04/18/2012] [Accepted: 04/20/2012] [Indexed: 10/28/2022]
Abstract
Decompression syndrome (caisson disease or the "the bends") resulting in avascular necrosis has been documented in mosasaurs, sauropterygians, ichthyosaurs, and turtles from the Middle Jurassic to Late Cretaceous, but it was unclear that this disease occurred as far back as the Triassic. We have examined a large Triassic sample of ichthyosaurs and compared it with an equally large post-Triassic sample. Avascular necrosis was observed in over 15% of Late Middle Jurassic to Cretaceous ichthyosaurs with the highest occurrence (18%) in the Early Cretaceous, but was rare or absent in geologically older specimens. Triassic reptiles that dive were either physiologically protected, or rapid changes of their position in the water column rare and insignificant enough to prevent being recorded in the skeleton. Emergency surfacing due to a threat from an underwater predator may be the most important cause of avascular necrosis for air-breathing divers, with relative frequency of such events documented in the skeleton. Diving in the Triassic appears to have been a "leisurely" behavior until the evolution of large predators in the Late Jurassic that forced sudden depth alterations contributed to a higher occurrence of bends.
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Thomson JA, Cooper AB, Burkholder DA, Heithaus MR, Dill LM. Heterogeneous patterns of availability for detection during visual surveys: spatiotemporal variation in sea turtle dive-surfacing behaviour on a feeding ground. Methods Ecol Evol 2011. [DOI: 10.1111/j.2041-210x.2011.00163.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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28
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Wirsing AJ, Heithaus MR, Dill LM. Predator-induced modifications to diving behavior vary with foraging mode. OIKOS 2010. [DOI: 10.1111/j.1600-0706.2010.18844.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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29
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Pratt KL, Franklin CE. Temperature independence of aquatic oxygen uptake in an air-breathing ectotherm and the implications for dive duration. Comp Biochem Physiol A Mol Integr Physiol 2010; 156:42-5. [PMID: 20026237 DOI: 10.1016/j.cbpa.2009.12.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2009] [Revised: 12/10/2009] [Accepted: 12/11/2009] [Indexed: 11/29/2022]
Affiliation(s)
- Kirstin L Pratt
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland, Australia.
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Pratt KL, Franklin CE. Predator or prey? The dive response to aerial and aquatic predators of Arafura filesnakes. AUST J ZOOL 2009. [DOI: 10.1071/zo09080] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
In air-breathing aquatic animals, predation is a strong selection pressure that may be reduced by modification to diving patterns. The risk of predation increases with time spent at the surface, thus shorter, more frequent surfacing events or longer, less frequent surfacing events would decrease predation risk. A reduction in time spent on the surface can be achieved by use of bimodal respiration, which is an ability to extend dive duration using dissolved oxygen to supplement aerially acquired oxygen. Air is a more efficient respiratory medium; however, under predation pressure, the cost of surfacing increases and the reliance on aquatic gas exchange should therefore increase. We tested whether the bimodally respiring filesnake (Acrochordus arafurae) changed its diving behaviour under simulated aerial (model bird) and aquatic (large fish) predation. Aerial predation did not alter dive or surface duration, percentage time surfacing or activity. However, a greater number of longer dives were observed with fewer long surface intervals, suggesting an increase in the use of aquatic gas exchange. The diel diving patterns (short night dives, long day dives) may provide an in-built antipredatory response to aerial predation. The threat of aquatic predation produced atypical antipredator behaviour, with longer surface intervals, shorter dives and increased activity, indicating that piscivorous filesnakes may have identified the predatory fish as prey rather than a predator.
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32
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Clark NJ, Gordos MA, Franklin CE. Diving behaviour, aquatic respiration and blood respiratory properties: a comparison of hatchling and juvenile Australian turtles. J Zool (1987) 2008. [DOI: 10.1111/j.1469-7998.2008.00454.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Clark N, Gordos M, Franklin C. Thermal Plasticity of Diving Behavior, Aquatic Respiration, and Locomotor Performance in the Mary River TurtleElusor macrurus. Physiol Biochem Zool 2008; 81:301-9. [DOI: 10.1086/528779] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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MATTHIOPOULOS J, SMOUT S, WINSHIP AJ, THOMPSON D, BOYD IL, HARWOOD J. Getting beneath the surface of marine mammal – fisheries competition. Mamm Rev 2008. [DOI: 10.1111/j.1365-2907.2008.00123.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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36
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How long does a dive last? Foraging decisions by breath-hold divers in a patchy environment: a test of a simple model. Anim Behav 2007. [DOI: 10.1016/j.anbehav.2006.06.022] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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37
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38
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Can dive cycle models predict patterns of foraging behaviour? Diving by common eiders in an Arctic polynya. Anim Behav 2007. [DOI: 10.1016/j.anbehav.2006.10.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Halsey LG, Butler PJ. Optimal diving behaviour and respiratory gas exchange in birds. Respir Physiol Neurobiol 2006; 154:268-83. [PMID: 16884962 DOI: 10.1016/j.resp.2006.01.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2005] [Revised: 01/21/2006] [Accepted: 01/23/2006] [Indexed: 11/28/2022]
Abstract
This review discusses the advancements in our understanding of the physiology and behaviour of avian diving that have been underpinned by optimal foraging theory and the testing of optimal models. To maximise their foraging efficiency during foraging periods, diving birds must balance numerous factors that are directly or indirectly related to the replenishment of the oxygen stores and the removal of excess carbon dioxide. These include (1) the time spent underwater (which diminishes the oxygen supply, increases carbon dioxide levels and may even include a build up of lactate due to anaerobic metabolism), (2) the time spent at the surface recovering from the previous dive and preparing for the next (including reloading their oxygen supply, decreasing their carbon dioxide levels and possibly also metabolising lactate) and (3) the trade-off between maximising oxygen reserves for consumption underwater by taking in more air to the respiratory system, and minimising the energy costs of positive buoyancy caused by this air, to maximise the time available underwater to forage. Due to its importance in avian diving, replenishment of the oxygen stores has become integral to models of optimal diving, which predict the time budgeting of animals foraging underwater. While many of these models have been examined qualitatively, such tests of predictive trends appear fallible and only quantifiable support affords strong evidence of their predictive value. This review describes how the quantification of certain optimal diving models, using tufted ducks, indeed demonstrates some predictive success. This suggests that replenishment of the oxygen stores and removal of excess carbon dioxide have significant influences on the duration of the surface period between dives. Nevertheless, present models are too simplistic to be robust predictors of diving behaviour for individual animals and it is proposed that they require refinement through the incorporation of other variables that also influence diving behaviour such as, perhaps, prey density and predator avoidance.
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Affiliation(s)
- Lewis G Halsey
- Centre for Ornithology, School of Biosciences, University of Birmingham, Edgbaston B15 2TT, United Kingdom.
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Green JA, Halsey LG, Butler PJ. To What Extent Is the Foraging Behaviour of Aquatic Birds Constrained by Their Physiology? Physiol Biochem Zool 2005; 78:766-81. [PMID: 16075394 DOI: 10.1086/432423] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/03/2004] [Indexed: 11/03/2022]
Abstract
Aquatic birds have access to limited amounts of usable oxygen when they forage (dive) underwater, so the major physiological constraint to their behaviour is the need to periodically visit the water surface to replenish these stores and remove accumulated carbon dioxide. The size of the oxygen stores and the rate at which they are used (V dot o2) or carbon dioxide accumulates are the ultimate determinants of the duration that aquatic birds can remain feeding underwater. However, the assumption that the decision to terminate a dive is governed solely by the level of the respiratory stores is not always valid. Quantification of an optimal diving model for tufted ducks (Aythya fuligula) shows that while they dive efficiently by spending a minimum amount of time on the surface to replenish the oxygen used during a dive, they dive with nearly full oxygen stores and surface well before these stores are exhausted. The rates of carbon dioxide production during dives and removal during surface intervals are likely to be at least as important a constraint as oxygen; thus, further developments of optimal diving models should account for their effects. In the field, diving birds will adapt to changing environmental conditions and often maximise the time spent submerged during diving bouts. However, other factors influence the diving depths and durations of aquatic birds, and in some circumstances they are unable to forage sufficiently well to provide food for their offspring. The latest developments in telemetry have demonstrated how diving birds can make physiological decisions based on complex environmental factors. Diving penguins can control their inhaled air volume to match the expected depth, likely prey encounter rate, and buoyancy challenges of the following dive.
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Affiliation(s)
- Jonathan A Green
- School of Biosciences, University of Birmingham, Edgbaston B15 2TT, United Kingdom.
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Seebacher F, Franklin CE, Read M. Diving behaviour of a reptile (Crocodylus johnstoni) in the wild: interactions with heart rate and body temperature. Physiol Biochem Zool 2005; 78:1-8. [PMID: 15702457 DOI: 10.1086/425192] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/16/2004] [Indexed: 11/03/2022]
Abstract
The differences in physical properties of air and water pose unique behavioural and physiological demands on semiaquatic animals. The aim of this study was to describe the diving behaviour of the freshwater crocodile Crocodylus johnstoni in the wild and to assess the relationships between diving, body temperature, and heart rate. Time-depth recorders, temperature-sensitive radio transmitters, and heart rate transmitters were deployed on each of six C. johnstoni (4.0-26.5 kg), and data were obtained from five animals. Crocodiles showed the greatest diving activity in the morning (0600-1200 hours) and were least active at night, remaining at the water surface. Surprisingly, activity pattern was asynchronous with thermoregulation, and activity was correlated to light rather than to body temperature. Nonetheless, crocodiles thermoregulated and showed a typical heart rate hysteresis pattern (heart rate during heating greater than heart rate during cooling) in response to heating and cooling. Additionally, dive length decreased with increasing body temperature. Maximum diving length was 119.6 min, but the greatest proportion of diving time was spent on relatively short (<45 min) and shallow (<0.4 m) dives. A bradycardia was observed during diving, although heart rate during submergence was only 12% lower than when animals were at the surface.
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Affiliation(s)
- Frank Seebacher
- School of Biological Sciences A08, University of Sydney, Sydney, New South Wales 2006, Australia.
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Abstract
Ducks, fur seals, Weddell seals and probably most cetaceans seem to be able to dive and remain aerobic for durations that are consistent with their elevated stores of usable oxygen and their metabolic rate while diving being similar to that when they are resting at the surface of the water. Ducks, in fact, have a high metabolic rate while diving, mainly because of their large positive buoyancy, but other species have relatively low buoyancy, are better streamlined and use lift-based rather than drag-based propulsion. However, species such as the larger penguins, grey seals and elephant seals seem to achieve the impossible by performing a substantial proportion of their dives for periods longer than would be expected on the above assumptions, and yet remaining aerobic. The logical conclusion is that during such dives these species reduce their metabolic rate below the resting level (hypometabolism) and, in some of them, there is a regional reduction in body temperature (hypothermia) which may contribute to the reduction in metabolic rate.
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Affiliation(s)
- Patrick J Butler
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK.
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Wilson RP, Quintana F. Surface pauses in relation to dive duration in imperial cormorants; how much time for a breather? J Exp Biol 2004; 207:1789-96. [PMID: 15107434 DOI: 10.1242/jeb.00967] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARYAir-breathing animals diving to forage can optimize time underwater by diving with just enough oxygen for the projected performance underwater. By so doing they surface with minimal body oxygen levels, which leads to maximal rates of oxygen uptake. We examined whether imperial cormorants Phalacrocorax atriceps adhere to this by examining dive:pause ratios in birds diving for extended, continuous periods to constant depths, assuming that the oxygen used underwater was exactly replenished by the periods at the surface. Examination of the cumulative time spent in surface pauses relative to the cumulative time spent in diving showed that surface pauses increase according to a power curve function of time spent in the dive or water depth. In a simplistic model we considered the rate at which birds expended energy underwater to be constant and that the rate of oxygen replenishment during the surface pause was directly proportional to the oxygen deficit. We then worked out values for the rate constant for the surface pause before using this constant to examine bird body oxygen levels immediately pre- and post dive. The model predicted that imperial cormorants do not submerge with just enough oxygen to cover their projected dive performance but rather dive with substantial reserves, although these reserves decrease with increasing dive depth/duration. We speculate that these oxygen reserves may be used to enhance bird survival when rare events, such as the appearance of predators or discovery of large prey requiring extended handling time, occur. The form of the oxygen saturation curve over time at the surface means that the time costs for maintaining constant oxygen reserves become particularly onerous for long,deep dives, so the observed decrease in reserves with increasing dive duration is expected in animals benefiting by optimizing for time.
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Affiliation(s)
- Rory P Wilson
- Institut für Meereskunde, Düsternbrooker Weg 20, D-24105 Kiel, Germany.
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Halsey L, Reed JZ, Woakes A, Butler P. The influence of oxygen and carbon dioxide on diving behaviour of tufted ducks, Aythya fuligula. Physiol Biochem Zool 2003; 76:436-46. [PMID: 13130424 DOI: 10.1086/375658] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/04/2003] [Indexed: 11/03/2022]
Abstract
While optimal diving models focus on the diver's oxygen (O(2)) stores as the predominant factor influencing diving behaviour, many vertebrate species surface from a dive before these stores are exhausted and may commence another dive well after their O(2) stores have been resaturated. This study investigates the influence of hypoxia and also hypercapnia on the dive cycle of tufted ducks, Aythya fuligula, in terms of surface duration and dive duration. The birds were trained to surface into a respirometer box after each dive to a feeding tray so that rates of O(2) uptake (VO2) and carbon dioxide output (VCO2) at the surface could be measured. Although Vco2 initially lagged behind Vo2, both respiratory gas stores were close to full adjustment after the average surface duration, indicating that they probably had a similar degree of influence on surface duration. Chemoreceptors, which are known to influence diving behaviour, detect changes in O(2) and CO(2) partial pressures in the arterial blood. Thus, the need to restore blood gas levels appears to be a strong stimulus to continue ventilation. Mean surface duration coincided with peak instantaneous respiratory exchange ratio due to predive anticipatory hyperventilation causing hypocapnia. For comparison, the relationship between surface duration and O(2) uptake in reanalysed data for two grey seals indicated that one animal tended to dive well after fully restocking its O(2) stores, while the other dived at the point of full restocking. More CO(2) is exchanged than O(2) in tufted ducks during the last few breaths before the first dive of a bout, serving to reduce CO(2) stores and suggesting that hypercapnia rather than hypoxia is more often the limiting factor on asphyxia tolerance during dives. Indeed, according to calculations of O(2) stores and O(2) consumption rates over modal diving durations, a lack of O(2) does not seem to be associated with the termination of a dive in tufted ducks. However, factors other than CO(2) are also likely to be important, and perhaps more so, such as food density and rate of food ingestion. Because some predictive success has been demonstrated for optimal diving models, they should continue to incorporate O(2) stores as a variable, but their validity is likely to be improved by also focusing on CO(2) stores.
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Affiliation(s)
- Lewis Halsey
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, United Kingdom.
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