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Beltran RS, Lozano RR, Morris PA, Robinson PW, Holser RR, Keates TR, Favilla AB, Kilpatrick AM, Costa DP. Individual variation in life-history timing: synchronous presence, asynchronous events and phenological compensation in a wild mammal. Proc Biol Sci 2024; 291:20232335. [PMID: 38628129 PMCID: PMC11021928 DOI: 10.1098/rspb.2023.2335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Accepted: 03/14/2024] [Indexed: 04/19/2024] Open
Abstract
Many animals and plants have species-typical annual cycles, but individuals vary in their timing of life-history events. Individual variation in fur replacement (moult) timing is poorly understood in mammals due to the challenge of repeated observations and longitudinal sampling. We examined factors that influence variation in moult duration and timing among elephant seals (Mirounga angustirostris). We quantified the onset and progression of fur loss in 1178 individuals. We found that an exceptionally rapid visible moult (7 days, the shortest of any mammals or birds), and a wide range of moult start dates (spanning 6-10× the event duration) facilitated high asynchrony across individuals (only 20% of individuals in the population moulting at the same time). Some of the variation was due to reproductive state, as reproductively mature females that skipped a breeding season moulted a week earlier than reproductive females. Moreover, individual variation in timing and duration within age-sex categories far outweighed (76-80%) variation among age-sex categories. Individuals arriving at the end of the moult season spent 50% less time on the beach, which allowed them to catch up in their annual cycles and reduce population-level variance during breeding. These findings underscore the importance of individual variation in annual cycles.
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Affiliation(s)
- Roxanne S. Beltran
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA 95060, USA
| | - Raquel R. Lozano
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA 95060, USA
| | - Patricia A. Morris
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA 95060, USA
| | - Patrick W. Robinson
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA 95060, USA
| | - Rachel R. Holser
- Institute of Marine Sciences, University of California Santa Cruz, Santa Cruz, CA 95060, USA
| | - Theresa R. Keates
- Department of Ocean Sciences, University of California Santa Cruz, Santa Cruz, CA 95060, USA
| | - Arina B. Favilla
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA 95060, USA
| | - A. Marm Kilpatrick
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA 95060, USA
| | - Daniel P. Costa
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA 95060, USA
- Institute of Marine Sciences, University of California Santa Cruz, Santa Cruz, CA 95060, USA
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Peterson SH, Peterson MG, Ackerman JT, Debier C, Goetsch C, Holser RR, Hückstädt LA, Johnson JC, Keates TR, McDonald BI, McHuron EA, Costa DP. Foraging behavior and age affect maternal transfer of mercury to northern elephant seal pups. Sci Rep 2024; 14:4693. [PMID: 38409311 PMCID: PMC10897339 DOI: 10.1038/s41598-024-54527-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 02/13/2024] [Indexed: 02/28/2024] Open
Abstract
Deep ocean foraging northern elephant seals (Mirounga angustirostris) consume fish and squid in remote depths of the North Pacific Ocean. Contaminants bioaccumulated from prey are subsequently transferred by adult females to pups during gestation and lactation, linking pups to mercury contamination in mesopelagic food webs (200-1000 m depths). Maternal transfer of mercury to developing seal pups was related to maternal mercury contamination and was strongly correlated with maternal foraging behavior (biotelemetry and isotopes). Mercury concentrations in lanugo (hair grown in utero) were among the highest observed worldwide for young pinnipeds (geometric mean 23.01 μg/g dw, range 8.03-63.09 μg/g dw; n = 373); thus, some pups may be at an elevated risk of sub-lethal adverse health effects. Fetal mercury exposure was affected by maternal foraging geographic location and depth; mercury concentrations were highest in pups of the deepest diving, pelagic females. Moreover, pup lanugo mercury concentrations were strongly repeatable among successive pups of individual females, demonstrating relative consistency in pup mercury exposure based on maternal foraging strategies. Northern elephant seals are biosentinels of a remote deep-sea ecosystem. Our results suggest that mercury within North Pacific mesopelagic food webs may also pose an elevated risk to other mesopelagic-foraging predators and their offspring.
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Affiliation(s)
- Sarah H Peterson
- Western Ecological Research Center, Dixon Field Station, U.S. Geological Survey, 800 Business Park Drive Suite D, Dixon, CA, USA.
- Institute of Marine Sciences, University of California Santa Cruz, Santa Cruz, CA, USA.
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, USA.
| | - Michael G Peterson
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Joshua T Ackerman
- Western Ecological Research Center, Dixon Field Station, U.S. Geological Survey, 800 Business Park Drive Suite D, Dixon, CA, USA
| | - Cathy Debier
- Louvain Institute of Biomolecular Science and Technology, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Chandra Goetsch
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, USA
- CSS, Inc, Fairfax, VA, USA
| | - Rachel R Holser
- Institute of Marine Sciences, University of California Santa Cruz, Santa Cruz, CA, USA
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Luis A Hückstädt
- Institute of Marine Sciences, University of California Santa Cruz, Santa Cruz, CA, USA
- Centre for Ecology and Conservation, University of Exeter, Penryn, UK
| | - Jennifer C Johnson
- Moss Landing Marine Labs, San Jose State University, Moss Landing, CA, USA
| | - Theresa R Keates
- Department of Ocean Sciences, University of California Santa Cruz, Santa Cruz, CA, USA
| | | | - Elizabeth A McHuron
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Daniel P Costa
- Institute of Marine Sciences, University of California Santa Cruz, Santa Cruz, CA, USA
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, USA
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Holser RR, Crocker DE, Favilla AR, Adachi T, Keates TR, Naito Y, Costa DP. Effects of disease on foraging behaviour and success in an individual free-ranging northern elephant seal. Conserv Physiol 2023; 11:coad034. [PMID: 37250476 PMCID: PMC10214463 DOI: 10.1093/conphys/coad034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 04/14/2023] [Accepted: 05/17/2023] [Indexed: 05/31/2023]
Abstract
Evaluating consequences of stressors on vital rates in marine mammals is of considerable interest to scientific and regulatory bodies. Many of these species face numerous anthropogenic and environmental disturbances. Despite its importance as a critical form of mortality, little is known about disease progression in air-breathing marine megafauna at sea. We examined the movement, diving, foraging behaviour and physiological state of an adult female northern elephant seal (Mirounga angustirostris) who suffered from an infection while at sea. Comparing her to healthy individuals, we identified abnormal behavioural patterns from high-resolution biologging instruments that are likely indicators of diseased and deteriorating condition. We observed continuous extended (3-30 minutes) surface intervals coinciding with almost no foraging attempts (jaw motion) during 2 weeks of acute illness early in her post-breeding foraging trip. Elephant seals typically spend ~ 2 minutes at the surface. There were less frequent but highly extended (30-200 minutes) surface periods across the remainder of the trip. Dive duration declined throughout the trip rather than increasing. This seal returned in the poorest body condition recorded for an adult female elephant seal (18.3% adipose tissue; post-breeding trip average is 30.4%). She was immunocompromised at the end of her foraging trip and has not been seen since that moulting season. The timing and severity of the illness, which began during the end of the energy-intensive lactation fast, forced this animal over a tipping point from which she could not recover. Additional physiological constraints to foraging, including thermoregulation and oxygen consumption, likely exacerbated her already poor condition. These findings improve our understanding of illness in free-ranging air-breathing marine megafauna, demonstrate the vulnerability of individuals at critical points in their life history, highlight the importance of considering individual health when interpreting biologging data and could help differentiate between malnutrition and other causes of at-sea mortality from transmitted data.
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Affiliation(s)
- Rachel R Holser
- Corresponding author: Institute of Marine Sciences, University of California Santa Cruz, 115 McAllister Way, Santa Cruz, CA, 95060, USA. Tel.: +1 253-514-0110.
| | - Daniel E Crocker
- Department of Biology, Sonoma State University, Rohnert Park, California, 94928, USA
| | - Arina R Favilla
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, California, 95064 USA
| | - Taiki Adachi
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, California, 95064 USA
- National Institute of Polar Research, Tachikawa, Tokyo, Japan
| | - Theresa R Keates
- Department of Ocean Sciences, University of California Santa Cruz, Santa Cruz, California, 95064, USA
| | - Yasuhiko Naito
- National Institute of Polar Research, Tachikawa, Tokyo, Japan
| | - Daniel P Costa
- Institute of Marine Sciences, University of California Santa Cruz, 115 McAllister Way, Santa Cruz, CA, 95060, USA
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, California, 95064 USA
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Adachi T, Lovell P, Turnbull J, Fedak MA, Picard B, Guinet C, Biuw M, Keates TR, Holser RR, Costa DP, Crocker DE, Miller PJO. Body condition changes at sea: Onboard calculation and telemetry of body density in diving animals. Methods Ecol Evol 2023. [DOI: 10.1111/2041-210x.14089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023]
Affiliation(s)
- Taiki Adachi
- Sea Mammal Research Unit University of St Andrews St Andrews UK
- Department of Ecology and Evolutionary Biology University of California Santa Cruz Santa Cruz California USA
| | - Philip Lovell
- Sea Mammal Research Unit University of St Andrews St Andrews UK
| | - James Turnbull
- Sea Mammal Research Unit University of St Andrews St Andrews UK
| | - Mike A. Fedak
- Sea Mammal Research Unit University of St Andrews St Andrews UK
| | - Baptiste Picard
- CNRS Centre of Biology Studies of Chizé Villiers‐en‐Bois France
| | | | | | - Theresa R. Keates
- Department of Ocean Sciences University of California Santa Cruz Santa Cruz California USA
| | - Rachel R. Holser
- Institute of Marine Sciences, University of California Santa Cruz Santa Cruz California USA
| | - Daniel P. Costa
- Department of Ecology and Evolutionary Biology University of California Santa Cruz Santa Cruz California USA
- Institute of Marine Sciences, University of California Santa Cruz Santa Cruz California USA
| | - Daniel E. Crocker
- Department of Biology Sonoma State University Rohnert Park California USA
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Adachi T, Takahashi A, Costa DP, Robinson PW, Hückstädt LA, Peterson SH, Holser RR, Beltran RS, Keates TR, Naito Y. Forced into an ecological corner: Round-the-clock deep foraging on small prey by elephant seals. Sci Adv 2021; 7:7/20/eabg3628. [PMID: 33980496 PMCID: PMC8115928 DOI: 10.1126/sciadv.abg3628] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 03/22/2021] [Indexed: 06/01/2023]
Abstract
Small mesopelagic fishes dominate the world's total fish biomass, yet their ecological importance as prey for large marine animals is poorly understood. To reveal the little-known ecosystem dynamics, we identified prey, measured feeding events, and quantified the daily energy balance of 48 deep-diving elephant seals throughout their oceanic migrations by leveraging innovative technologies: animal-borne smart accelerometers and video cameras. Seals only attained positive energy balance after feeding 1000 to 2000 times per day on small fishes, which required continuous deep diving (80 to 100% of each day). Interspecies allometry suggests that female elephant seals have exceptional diving abilities relative to their body size, enabling them to exploit a unique foraging niche on small but abundant mesopelagic fish. This unique foraging niche requires extreme round-the-clock deep diving, limiting the behavioral plasticity of elephant seals to a changing mesopelagic ecosystem.
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Affiliation(s)
- Taiki Adachi
- National Institute of Polar Research, Tachikawa, Tokyo, Japan.
| | | | - Daniel P Costa
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, USA
- Institute of Marine Sciences, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Patrick W Robinson
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Luis A Hückstädt
- Institute of Marine Sciences, University of California Santa Cruz, Santa Cruz, CA, USA
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, NC, USA
| | - Sarah H Peterson
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, USA
- Institute of Marine Sciences, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Rachel R Holser
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Roxanne S Beltran
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Theresa R Keates
- Department of Ocean Sciences, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Yasuhiko Naito
- National Institute of Polar Research, Tachikawa, Tokyo, Japan
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Sequeira AMM, O'Toole M, Keates TR, McDonnell LH, Braun CD, Hoenner X, Jaine FRA, Jonsen ID, Newman P, Pye J, Bograd SJ, Hays GC, Hazen EL, Holland M, Tsontos VM, Blight C, Cagnacci F, Davidson SC, Dettki H, Duarte CM, Dunn DC, Eguíluz VM, Fedak M, Gleiss AC, Hammerschlag N, Hindell MA, Holland K, Janekovic I, McKinzie MK, Muelbert MMC, Pattiaratchi C, Rutz C, Sims DW, Simmons SE, Townsend B, Whoriskey F, Woodward B, Costa DP, Heupel MR, McMahon CR, Harcourt R, Weise M. A standardisation framework for bio‐logging data to advance ecological research and conservation. Methods Ecol Evol 2021. [DOI: 10.1111/2041-210x.13593] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Schwarz D, Spitzer SM, Thomas AC, Kohnert CM, Keates TR, Acevedo‐Gutiérrez A. Large-scale molecular diet analysis in a generalist marine mammal reveals male preference for prey of conservation concern. Ecol Evol 2018; 8:9889-9905. [PMID: 30386584 PMCID: PMC6202700 DOI: 10.1002/ece3.4474] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 07/12/2018] [Accepted: 07/13/2018] [Indexed: 11/12/2022] Open
Abstract
Sex-specific diet information is important in the determination of predator impacts on prey populations. Unfortunately, the diet of males and females can be difficult to describe, particularly when they are marine predators. We combined two molecular techniques to describe haul-out use and prey preferences of male and female harbor seals (Phoca vitulina) from Comox and Cowichan Bay (Canada) during 2012-2013. DNA metabarcoding quantified the diet proportions comprised of prey species in harbor seal scat, and qPCR determined the sex of the individual that deposited each scat. Using 287 female and 260 male samples, we compared the monthly sex ratio with GLMs and analyzed prey consumption relative to sex, season, site, and year with PERMANOVA. The sex ratio between monthly samples differed widely in both years (range = 12%-79% males) and showed different patterns at each haul-out site. Male and female diet differed across both years and sites: Females consumed a high proportion of demersal fish species while males consumed more salmonid species. Diet composition was related to both sex and season (PERMANOVA: R 2 = 27%, p < 0.001; R 2 = 24%, p < 0.001, respectively) and their interaction (PERMANOVA: R 2 = 11%, p < 0.001). Diet differences between males and females were consistent across site and year, suggesting fundamental foraging differences, including that males may have a larger impact on salmonids than females. Our novel combination of techniques allowed for both prey taxonomic and spatiotemporal resolution unprecedented in marine predators.
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Affiliation(s)
- Dietmar Schwarz
- Department of BiologyWestern Washington UniversityBellinghamWashington
| | - Sara M. Spitzer
- Department of BiologyWestern Washington UniversityBellinghamWashington
- Present address:
Illumina Inc.San DiegoCalifornia
| | - Austen C. Thomas
- Department of Zoology and Marine Mammal Research UnitInstitute for the Oceans and FisheriesUniversity of British ColumbiaVancouverBritish ColumbiaCanada
- Smith‐RootVancouverWashington
| | | | - Theresa R. Keates
- Department of BiologyWestern Washington UniversityBellinghamWashington
- Present address:
Department of Ocean SciencesUniversity of CaliforniaSanta CruzCalifornia
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