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Reynolds SD, Franklin CE, Norman BM, Richardson AJ, Everett JD, Schoeman DS, White CR, Lawson CL, Pierce SJ, Rohner CA, Bach SS, Comezzi FG, Diamant S, Jaidah MY, Robinson DP, Dwyer RG. Effects of climate warming on energetics and habitat of the world's largest marine ectotherm. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 951:175832. [PMID: 39197762 DOI: 10.1016/j.scitotenv.2024.175832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 08/23/2024] [Accepted: 08/25/2024] [Indexed: 09/01/2024]
Abstract
Responses of organisms to climate warming are variable and complex. Effects on species distributions are already evident and mean global surface ocean temperatures are likely to warm by up to 4.1 °C by 2100, substantially impacting the physiology and distributions of ectotherms. The largest marine ectotherm, the whale shark Rhincodon typus, broadly prefers sea surface temperatures (SST) ranging from 23 to 30 °C. Whole-species distribution models have projected a poleward range shift under future scenarios of climate change, but these models do not consider intraspecific variation or phenotypic plasticity in thermal limits when modelling species responses, and the impact of climate warming on the energetic requirements of whale sharks is unknown. Using a dataset of 111 whale shark movement tracks from aggregation sites in five countries across the Indian Ocean and the latest Earth-system modelling produced from Coupled Model Intercomparison Project Phase 6 for the Intergovernmental Panel on Climate Change, we examined how SST and total zooplankton biomass, their main food source, may change in the future, and what this means for the energetic balance and extent of suitable habitat for whale sharks. Earth System Models, under three Shared Socioeconomic Pathways (SSPs; SSP1-2.6, SSP3-7.0 and SSP5-8.5), project that by 2100 mean SST in four regions where whale shark aggregations are found will increase by up to 4.9 °C relative to the present, while zooplankton biomass will decrease. This reduction in zooplankton is projected to be accompanied by an increase in the energetic requirements of whale sharks because warmer water temperatures will increase their metabolic rate. We found marked differences in projected changes in the extent of suitable habitat when comparing a whole-species distribution model to one including regional variation. This suggests that the conventional approach of combining data from different regions within a species' distribution could underestimate the amount of local adaptation in populations, although parameterising local models could also suffer from having insufficient data and lead to model mis-specification or highly uncertain estimates. Our study highlights the need for further research into whale shark thermal tolerances and energetics, the complexities involved in projecting species responses to climate change, and the potential importance of considering intraspecific variation when building species distribution models.
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Affiliation(s)
- Samantha D Reynolds
- School of the Environment, The University of Queensland, Brisbane, QLD, Australia; 162/3 Powell Rd, Coogee, WA, Australia; Harry Butler Institute, Murdoch University, Murdoch, WA, Australia.
| | - Craig E Franklin
- School of the Environment, The University of Queensland, Brisbane, QLD, Australia
| | - Bradley M Norman
- 162/3 Powell Rd, Coogee, WA, Australia; Harry Butler Institute, Murdoch University, Murdoch, WA, Australia
| | - Anthony J Richardson
- School of the Environment, The University of Queensland, Brisbane, QLD, Australia; Centre for Biodiversity and Conservation Science (CBCS), The University of Queensland, Brisbane, QLD, Australia; CSIRO Environment, Queensland Biosciences Precinct, St Lucia, QLD, AUSTRALIA
| | - Jason D Everett
- School of the Environment, The University of Queensland, Brisbane, QLD, Australia; CSIRO Environment, Queensland Biosciences Precinct, St Lucia, QLD, AUSTRALIA; Centre for Marine Science and Innovation, University of New South Wales, Sydney, NSW, Australia
| | - David S Schoeman
- Ocean Futures Research Cluster, School of Science, Technology, and Engineering, University of the Sunshine Coast, Maroochydore, QLD, Australia; Centre for African Conservation Ecology, Department of Zoology, Nelson Mandela University, Gqeberha, South Africa
| | - Craig R White
- School of Biological Sciences and Centre for Geometric Biology, Monash University, Clayton, VIC, Australia
| | - Christopher L Lawson
- School of the Environment, The University of Queensland, Brisbane, QLD, Australia
| | - Simon J Pierce
- Marine Megafauna Foundation, West Palm Beach, FL, USA; School of Science, Technology and Engineering, The University of the Sunshine Coast, Sippy Downs, QLD, Australia
| | | | - Steffen S Bach
- Ramboll, Copenhagen, Denmark; Qatar Whale Shark Research Project, Doha, Qatar
| | - Francesco G Comezzi
- Department of Natural Resources and Environment Tasmania, Marine Resources, Hobart, Tasmania, Australia
| | - Stella Diamant
- Marine Megafauna Foundation, West Palm Beach, FL, USA; Madagascar Whale Shark Project, Nosy Be, Madagascar
| | - Mohammed Y Jaidah
- Qatar Whale Shark Research Project, Doha, Qatar; Sundive Research, Byron Bay, New South Wales, Australia
| | - David P Robinson
- Qatar Whale Shark Research Project, Doha, Qatar; Sundive Research, Byron Bay, New South Wales, Australia
| | - Ross G Dwyer
- School of Science, Technology and Engineering, The University of the Sunshine Coast, Sippy Downs, QLD, Australia
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Gilmour KM, Daley MA, Egginton S, Kelber A, McHenry MJ, Patek SN, Sane SP, Schulte PM, Terblanche JS, Wright PA, Franklin CE. Through the looking glass: attempting to predict future opportunities and challenges in experimental biology. J Exp Biol 2023; 226:jeb246921. [PMID: 38059428 DOI: 10.1242/jeb.246921] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2023]
Abstract
To celebrate its centenary year, Journal of Experimental Biology (JEB) commissioned a collection of articles examining the past, present and future of experimental biology. This Commentary closes the collection by considering the important research opportunities and challenges that await us in the future. We expect that researchers will harness the power of technological advances, such as '-omics' and gene editing, to probe resistance and resilience to environmental change as well as other organismal responses. The capacity to handle large data sets will allow high-resolution data to be collected for individual animals and to understand population, species and community responses. The availability of large data sets will also place greater emphasis on approaches such as modeling and simulations. Finally, the increasing sophistication of biologgers will allow more comprehensive data to be collected for individual animals in the wild. Collectively, these approaches will provide an unprecedented understanding of 'how animals work' as well as keys to safeguarding animals at a time when anthropogenic activities are degrading the natural environment.
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Affiliation(s)
| | - Monica A Daley
- Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, CA 92697, USA
| | - Stuart Egginton
- School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Almut Kelber
- Department of Biology, Lund University, 22362 Lund, Sweden
| | - Matthew J McHenry
- Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, CA 92697, USA
| | - Sheila N Patek
- Biology Department, Duke University, Durham, NC 27708, USA
| | - Sanjay P Sane
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, GKVK Campus, Bellary Road, Bangalore, Karnataka 560065, India
| | - Patricia M Schulte
- Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - John S Terblanche
- Center for Invasion Biology, Department of Conservation Ecology & Entomology, Stellenbosch University, Stellenbosch 7602, South Africa
| | - Patricia A Wright
- Department of Integrative Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Craig E Franklin
- School of the Environment, The University of Queensland, St. Lucia, Brisbane 4072, Australia
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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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Hunting behavior of a solitary sailfish Istiophorus platypterus and estimated energy gain after prey capture. Sci Rep 2023; 13:1484. [PMID: 36707627 PMCID: PMC9883507 DOI: 10.1038/s41598-023-28748-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 01/24/2023] [Indexed: 01/29/2023] Open
Abstract
Foraging behavior and interaction with prey is an integral component of the ecological niche of predators but is inherently difficult to observe for highly mobile animals in the marine environment. Billfishes have been described as energy speculators, expending a large amount of energy foraging, expecting to offset high costs with periodic high energetic gain. Surface-based group feeding of sailfish, Istiophorus platypterus, is commonly observed, yet sailfish are believed to be largely solitary roaming predators with high metabolic requirements, suggesting that individual foraging also represents a major component of predator-prey interactions. Here, we use biologging data and video to examine daily activity levels and foraging behavior, estimate metabolic costs, and document a solitary predation event for a 40 kg sailfish. We estimate a median active metabolic rate of 218.9 ± 70.5 mgO2 kg-1 h-1 which increased to 518.8 ± 586.3 mgO2 kg-1 h-1 during prey pursuit. Assuming a successful predation, we estimate a daily net energy gain of 2.4 MJ (5.1 MJ acquired, 2.7 MJ expended), supporting the energy speculator model. While group hunting may be a common activity used by sailfish to acquire energy, our calculations indicate that opportunistic individual foraging events offer a net energy return that contributes to the fitness of these highly mobile predators.
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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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Wilson RP, Reynolds SD, Potts JR, Redcliffe J, Holton M, Buxton A, Rose K, Norman BM. Highlighting when animals expend excessive energy for travel using Dynamic Body Acceleration. iScience 2022; 25:105008. [PMID: 36105597 PMCID: PMC9464956 DOI: 10.1016/j.isci.2022.105008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 08/07/2022] [Accepted: 08/18/2022] [Indexed: 11/29/2022] Open
Abstract
Travel represents a major cost for many animals so there should be selection pressure for it to be efficient – at minimum cost. However, animals sometimes exceed minimum travel costs for reasons that must be correspondingly important. We use Dynamic Body Acceleration (DBA), an acceleration-based metric, as a proxy for movement-based power, in tandem with vertical velocity (rate of change in depth) in a shark (Rhincodon typus) to derive the minimum estimated power required to swim at defined vertical velocities. We show how subtraction of measured DBA from the estimated minimum power for any given vertical velocity provides a “proxy for power above minimum” metric (PPAmin), highlighting when these animals travel above minimum power. We suggest that the adoption of this metric across species has value in identifying where and when animals are subject to compelling conditions that lead them to deviate from ostensibly judicious energy expenditure. Plots of vertical speed vs DBA in sharks show swimming with minimum power DBA values above this minimum indicate higher speeds or increases in drag Linked to space use, this can identify regions and times of excess power use
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