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Rich G, Stennett R, Galloway M, McClure M, Riley R, Freeman EW, Hunt KE. Nailing it: Investigation of elephant toenails for retrospective analysis of adrenal and reproductive hormones. CONSERVATION PHYSIOLOGY 2024; 12:coae048. [PMID: 39100510 PMCID: PMC11295213 DOI: 10.1093/conphys/coae048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 06/25/2024] [Accepted: 07/15/2024] [Indexed: 08/06/2024]
Abstract
Hormone monitoring of at-risk species can be valuable for evaluation of individual physiological status. Traditional non-invasive endocrine monitoring from urine and faeces typically captures only a short window in time, poorly reflecting long-term hormone fluctuations. We examined toenail trimmings collected from African (Loxodonta africana) and Asian (Elephas maximus) elephants during routine foot care, to determine if long-term hormone patterns are preserved in these slow-growing keratinized tissues. We first measured the growth rate of elephant toenails biweekly for one year, to establish the temporal delay between deposition of hormones into nail tissue (at the proximal nail bed) and collection of toenail trimmings months later (at the distal tip of the nail). In African elephants, toenails grew ~0.18 ± 0.015 mm/day (mean ± SEM) and in Asian elephants, toenails grew ~0.24 ± 0.034 mm/day. This slow growth rate, combined with the large toenail size of elephants, may mean that toenails could contain a 'hormone timeline' of over a year between the nail bed and nail tip. Progesterone, testosterone and cortisol were readily detectable using commercial enzyme immunoassays, and all assays passed validations, indicating that these hormones can be accurately quantified in elephant toenail extract. In most cases, variations in hormone concentrations reflected expected physiological patterns for adult females and males (e.g. ovarian cycling and musth) and matched individual health records from participating zoos. Progesterone patterns aligned with our calculations of temporal delay, aligning with female ovarian cycling from over six months prior. Unexpectedly, male testosterone patterns aligned with current musth status at the time of sample collection (i.e. rather than prior musth status). Though this sample type will require further study, these results indicate that preserved hormone patterns in elephant toenails could give conservationists a new tool to aid management of elephant populations.
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Affiliation(s)
- Garrett Rich
- Department of Biology, George Mason University, 4400 University Drive, Fairfax, VA 22030, USA
| | - Rebecca Stennett
- The Maryland Zoo in Baltimore, 1 Safari Place Baltimore, MD 21217, USA
| | - Marie Galloway
- Smithsonian’s National Zoo and Conservation Biology Institute, 3001 Connecticut Ave NW, Washington, DC 20008, USA
| | - Mike McClure
- The Maryland Zoo in Baltimore, 1 Safari Place Baltimore, MD 21217, USA
| | - Rebecca Riley
- Smithsonian’s National Zoo and Conservation Biology Institute, 3001 Connecticut Ave NW, Washington, DC 20008, USA
| | - Elizabeth W Freeman
- School of Integrative Studies, George Mason University, 4400 University Drive, Fairfax, VA 22030, USA
| | - Kathleen E Hunt
- Department of Biology, George Mason University, 4400 University Drive, Fairfax, VA 22030, USA
- Smithsonian-Mason School of Conservation, 1500 Remount Road, Front Royal, VA 22630, USA
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Fernández Ajó A, Teixeira C, M D de Mello D, Dillon D, Rice JM, Buck CL, Hunt KE, Rogers MC, Torres LG. A longitudinal study of endocrinology and foraging ecology of subadult gray whales prior to death based on baleen analysis. Gen Comp Endocrinol 2024; 352:114492. [PMID: 38479678 DOI: 10.1016/j.ygcen.2024.114492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 03/04/2024] [Accepted: 03/06/2024] [Indexed: 03/18/2024]
Abstract
Individual-level assessments of wild animal health, vital rates, and foraging ecology are critical for understanding population-wide impacts of exposure to stressors. Large whales face multiple stressors, including, but not limited to, ocean noise, pollution, and ship strikes. Because baleen is a continuously growing keratinized structure, serial extraction, and quantification of hormones and stable isotopes along the length of baleen provide a historical record of whale physiology and foraging ecology. Furthermore, baleen analysis enables the investigation of dead specimens, even decades later, allowing comparisons between historic and modern populations. Here, we examined baleen of five sub-adult gray whales and observed distinct patterns of oscillations in δ15N values along the length of their baleen plates which enabled estimation of baleen growth rates and differentiation of isotopic niche widths of the whales during wintering and summer foraging. In contrast, no regular patterns were apparent in δ13C values. Prolonged elevation of cortisol in four individuals before death indicates that chronic stress may have impacted their health and survival. Triiodothyronine (T3) increased over months in the whales with unknown causes of death, simultaneous with elevations in cortisol, but both hormones remained stable in the one case of acute death attributed to killer whale predation. This parallel elevation of cortisol and T3 challenges the classic understanding of their interaction and might relate to increased energetic demands during exposure to stressors. Reproductive hormone profiles in subadults did not show cyclical trends, suggesting they had not yet reached sexual maturity. This study highlights the potential of baleen analysis to retrospectively assess gray whales' physiological status, exposure to stressors, reproductive status, and foraging ecology in the months or years leading up to their death, which can be a useful tool for conservation diagnostics to mitigate unusual mortality events.
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Affiliation(s)
- Alejandro Fernández Ajó
- Geospatial Ecology of Marine Megafauna Lab, Marine Mammal Institute, Department of Fisheries, Wildlife and Conservation Sciences, Oregon State University, Newport 97365, OR, USA.
| | - Clarissa Teixeira
- Marine Mammal Institute, Department of Fisheries, Wildlife and Conservation Sciences, Oregon State University, Newport 97365, OR, USA
| | - Daniela M D de Mello
- Department of Physiology, Institute of Bioscience, University of São Paulo, São Paulo 05508090, SP, Brazil
| | - Danielle Dillon
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - James M Rice
- Oregon Marine Mammal Stranding Network, Marine Mammal Institute, Oregon State University, Newport 97365, OR, USA
| | - C Loren Buck
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Kathleen E Hunt
- George Mason University & Smithsonian-Mason School of Conservation, 1500 Remount Rd, Front Royal, VA 22630, USA
| | - Matthew C Rogers
- NOAA, National Marine Fisheries Service, Alaska Fisheries Science Center Auke Bay Laboratories, Juneau, AK 99801, USA
| | - Leigh G Torres
- Geospatial Ecology of Marine Megafauna Lab, Marine Mammal Institute, Department of Fisheries, Wildlife and Conservation Sciences, Oregon State University, Newport 97365, OR, USA
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Agustí C, Manteca X, García-Párraga D, Tallo-Parra O. Validating a Non-Invasive Method for Assessing Cortisol Concentrations in Scraped Epidermal Skin from Common Bottlenose Dolphins and Belugas. Animals (Basel) 2024; 14:1377. [PMID: 38731382 PMCID: PMC11083227 DOI: 10.3390/ani14091377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 04/13/2024] [Accepted: 04/30/2024] [Indexed: 05/13/2024] Open
Abstract
Society is showing a growing concern about the welfare of cetaceans in captivity as well as cetaceans in the wild threatened by anthropogenic disturbances. The study of the physiological stress response is increasingly being used to address cetacean conservation and welfare issues. Within it, a newly described technique of extracting cortisol from epidermal desquamation may serve as a non-invasive, more integrated measure of a cetacean's stress response and welfare. However, confounding factors are common when measuring glucocorticoid hormones. In this study, we validated a steroid hormone extraction protocol and the use of a commercial enzyme immunoassay (EIA) test to measure cortisol concentrations in common bottlenose dolphin (Tursiops truncatus) and beluga (Delphinapterus leucas) epidermal samples. Moreover, we examined the effect of sample mass and body location on cortisol concentrations. Validation tests (i.e., assay specificity, accuracy, precision, and sensitivity) suggested that the method was suitable for the quantification of cortisol concentrations. Cortisol was extracted from small samples (0.01 g), but the amount of cortisol detected and the variability between duplicate extractions increased as the sample mass decreased. In common bottlenose dolphins, epidermal skin cortisol concentrations did not vary significantly across body locations while there was a significant effect of the individual. Overall, we present a contribution towards advancing and standardizing epidermis hormone assessments in cetaceans.
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Affiliation(s)
- Clara Agustí
- Animal Welfare Education Centre (AWEC), School of Veterinary Science, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain; (X.M.); (O.T.-P.)
| | - Xavier Manteca
- Animal Welfare Education Centre (AWEC), School of Veterinary Science, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain; (X.M.); (O.T.-P.)
| | - Daniel García-Párraga
- Fundación Oceanogràfic de la Comunitat Valenciana, Research Department, Ciudad de las Artes y las Ciencias, 46013 Valencia, Spain;
| | - Oriol Tallo-Parra
- Animal Welfare Education Centre (AWEC), School of Veterinary Science, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain; (X.M.); (O.T.-P.)
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Keogh MJ, Thompson DP, Crouse JA. Tracking reproductive events: Hoof growth and steroid hormone concentrations in hair and hoof tissues in moose ( Alces alces). CONSERVATION PHYSIOLOGY 2023; 11:coad097. [PMID: 38107464 PMCID: PMC10722880 DOI: 10.1093/conphys/coad097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 11/02/2023] [Accepted: 11/28/2023] [Indexed: 12/19/2023]
Abstract
Measurements of reproductive and stress-related hormones in keratinous tissues (e.g. hair, claws, hooves, baleen) can provide a record of stress and reproductive response in wildlife. We evaluated a method to collect keratin tissue from hooves of immobilized moose (Alces alces) and validated enzyme immunoassays for measuring cortisol and progesterone in hooves and hair. We also measured the annual growth and wear rates of moose hooves. Progesterone (range: 1.0-43.7 pg/mg) and cortisol (range: 0.05-2.9 pg/mg) were measurable and showed variation among hoof samples and moose. Pregnant females had twice as high progesterone concentrations (18.00 ± 3.73 pg/mg) from hoof sample locations post breeding compared to non-pregnant moose (9.40 ± 0.25 pg/mg). Annual hoof growth differed between the front (5.58 ± 0.12 cm) and rear (4.73 ± 0.13 cm) hooves and varied by season with higher growth rates during summer which decreased into autumn and winter. Adult female hooves represented between 1.6 and 2.1 years of growth and included up to two reproductive cycles. We established a method to estimate hoof growth rate and applied this to postmortem samples and were able to detect previous pregnancies. Shoulder guard hairs grew between August and March including during late gestation; however, hair progesterone concentrations (range: 2-107.1 pg/mg) were not related to reproductive state. Hair cortisol concentrations in our study (range: 0.2-15.9 pg/mg) were within the range of values previously reported for cervids. Our study supports the use of hooves for longitudinal sampling and measuring reproductive and stress-related hormones, providing a new tool for tracking reproductive events and understanding what variables may contribute to population level changes in reproduction.
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Affiliation(s)
- Mandy J Keogh
- Division of Wildlife Conservation, Alaska Department of Fish and Game, 802 3rd St, Douglas, AK 99801, USA
| | - Daniel P Thompson
- Kenai Moose Research Center, Alaska Department of Fish and Game, 43961 Kalifornsky Beach Road Suite B, Soldotna, AK 99669, USA
| | - John A Crouse
- Kenai Moose Research Center, Alaska Department of Fish and Game, 43961 Kalifornsky Beach Road Suite B, Soldotna, AK 99669, USA
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Barratclough A, Ferguson SH, Lydersen C, Thomas PO, Kovacs KM. A Review of Circumpolar Arctic Marine Mammal Health-A Call to Action in a Time of Rapid Environmental Change. Pathogens 2023; 12:937. [PMID: 37513784 PMCID: PMC10385039 DOI: 10.3390/pathogens12070937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 06/16/2023] [Accepted: 07/12/2023] [Indexed: 07/30/2023] Open
Abstract
The impacts of climate change on the health of marine mammals are increasingly being recognised. Given the rapid rate of environmental change in the Arctic, the potential ramifications on the health of marine mammals in this region are a particular concern. There are eleven endemic Arctic marine mammal species (AMMs) comprising three cetaceans, seven pinnipeds, and the polar bear (Ursus maritimus). All of these species are dependent on sea ice for survival, particularly those requiring ice for breeding. As air and water temperatures increase, additional species previously non-resident in Arctic waters are extending their ranges northward, leading to greater species overlaps and a concomitant increased risk of disease transmission. In this study, we review the literature documenting disease presence in Arctic marine mammals to understand the current causes of morbidity and mortality in these species and forecast future disease issues. Our review highlights potential pathogen occurrence in a changing Arctic environment, discussing surveillance methods for 35 specific pathogens, identifying risk factors associated with these diseases, as well as making recommendations for future monitoring for emerging pathogens. Several of the pathogens discussed have the potential to cause unusual mortality events in AMMs. Brucella, morbillivirus, influenza A virus, and Toxoplasma gondii are all of concern, particularly with the relative naivety of the immune systems of endemic Arctic species. There is a clear need for increased surveillance to understand baseline disease levels and address the gravity of the predicted impacts of climate change on marine mammal species.
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Affiliation(s)
- Ashley Barratclough
- National Marine Mammal Foundation, 2240 Shelter Island Drive, San Diego, CA 92106, USA
| | - Steven H. Ferguson
- Arctic Aquatic Research Division, Fisheries and Oceans Canada, Winnipeg, MB R3T 2N6, Canada;
| | - Christian Lydersen
- Norwegian Polar Institute, Fram Centre, 9296 Tromsø, Norway; (C.L.); (K.M.K.)
| | - Peter O. Thomas
- Marine Mammal Commission, 4340 East-West Highway, Room 700, Bethesda, MD 20814, USA;
| | - Kit M. Kovacs
- Norwegian Polar Institute, Fram Centre, 9296 Tromsø, Norway; (C.L.); (K.M.K.)
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Lysiak NSJ, Ferguson SH, Hornby CA, Heide-Jørgensen MP, Matthews CJD. Prolonged baleen hormone cycles suggest atypical reproductive endocrinology of female bowhead whales. ROYAL SOCIETY OPEN SCIENCE 2023; 10:230365. [PMID: 37501659 PMCID: PMC10369022 DOI: 10.1098/rsos.230365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 07/05/2023] [Indexed: 07/29/2023]
Abstract
Serial measurements of hormone concentrations along baleen plates allow for reconstructions of mysticete whale reproductive histories. We assessed gestation and calving interval in bowhead whales (Balaena mysticetus) by measuring progesterone, oestradiol, corticosterone and nitrogen stable isotope ratios (δ15N) along baleen of 10 females from the eastern Canada-west Greenland population. Three immature females (body size < 14.32 m) had uniformly low progesterone concentrations across their baleen, while seven mature females (body size ≥ 14.35 m) had repeated, sustained elevations of progesterone indicative of pregnancies. The mean duration of progesterone elevations (23.6 ± 1.50 months) was considerably longer than the approximately 14 month gestation previously estimated for this species. We consider several possible explanations for this observation, including delayed implantation or sequential ovulations prior to gestation, strategies that would allow females to maximize their fitness in variable Arctic conditions, as well as suggest modified criteria defining gestation as a shorter component of the entire progesterone peak. Calving intervals varied within and among individuals (mean = 3.7 years; range = range 2.8-5.7 years), providing population-specific reproductive estimates for growth models used in bowhead whale management and conservation.
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Affiliation(s)
- N. S. J. Lysiak
- Biology Department, Suffolk University, Boston, 02108, MA, USA
| | - S. H. Ferguson
- Arctic Aquatic Research Division, Fisheries and Oceans Canada, 501 University Crescent, Winnipeg, Manitoba, Canada R3T 2N6
| | - C. A. Hornby
- Arctic Aquatic Research Division, Fisheries and Oceans Canada, 501 University Crescent, Winnipeg, Manitoba, Canada R3T 2N6
| | | | - C. J. D. Matthews
- Arctic Aquatic Research Division, Fisheries and Oceans Canada, 501 University Crescent, Winnipeg, Manitoba, Canada R3T 2N6
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Beattie UK, Romero LM. Long term stability of corticosterone in feathers. Comp Biochem Physiol A Mol Integr Physiol 2023:111472. [PMID: 37390888 DOI: 10.1016/j.cbpa.2023.111472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 06/27/2023] [Accepted: 06/27/2023] [Indexed: 07/02/2023]
Abstract
Measuring corticosterone in feathers allows researchers to make long-term, retrospective assessments of physiology with non-invasive sampling. To date, there is little evidence that steroids degrade within the feather matrix, however this has yet to be determined from the same sample over many years. In 2009, we made a pool of European starling (Sturnus vulgaris) feathers that had been ground to a homogenous powder using a ball mill and stored on a laboratory bench. Over the past 14 years, a subset of this pooled sample has been assayed via radioimmunoassay (RIA) 19 times to quantify corticosterone. Despite high variability across time (though low variability within assays), there was no effect of time on measured feather corticosterone concentration. In contrast, two enzyme immunoassays (EIA) produced higher concentrations than the samples assayed with RIA, though this difference is likely due to different binding affinities of the antibodies used. The present study provides further support for researchers to use specimens stored long-term and from museums for feather corticosterone quantification, and likely applies to corticosteroid measurements in other keratinized tissues.
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Reis-Santos P, Gillanders BM, Sturrock AM, Izzo C, Oxman DS, Lueders-Dumont JA, Hüssy K, Tanner SE, Rogers T, Doubleday ZA, Andrews AH, Trueman C, Brophy D, Thiem JD, Baumgartner LJ, Willmes M, Chung MT, Charapata P, Johnson RC, Trumble S, Heimbrand Y, Limburg KE, Walther BD. Reading the biomineralized book of life: expanding otolith biogeochemical research and applications for fisheries and ecosystem-based management. REVIEWS IN FISH BIOLOGY AND FISHERIES 2023; 33:411-449. [PMID: 0 DOI: 10.1007/s11160-022-09720-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Accepted: 07/15/2022] [Indexed: 05/26/2023]
Abstract
AbstractChemical analysis of calcified structures continues to flourish, as analytical and technological advances enable researchers to tap into trace elements and isotopes taken up in otoliths and other archival tissues at ever greater resolution. Increasingly, these tracers are applied to refine age estimation and interpretation, and to chronicle responses to environmental stressors, linking these to ecological, physiological, and life-history processes. Here, we review emerging approaches and innovative research directions in otolith chemistry, as well as in the chemistry of other archival tissues, outlining their value for fisheries and ecosystem-based management, turning the spotlight on areas where such biomarkers can support decision making. We summarise recent milestones and the challenges that lie ahead to using otoliths and archival tissues as biomarkers, grouped into seven, rapidly expanding and application-oriented research areas that apply chemical analysis in a variety of contexts, namely: (1) supporting fish age estimation; (2) evaluating environmental stress, ecophysiology and individual performance; (3) confirming seafood provenance; (4) resolving connectivity and movement pathways; (5) characterising food webs and trophic interactions; (6) reconstructing reproductive life histories; and (7) tracing stock enhancement efforts. Emerging research directions that apply hard part chemistry to combat seafood fraud, quantify past food webs, as well as to reconcile growth, movement, thermal, metabolic, stress and reproductive life-histories provide opportunities to examine how harvesting and global change impact fish health and fisheries productivity. Ultimately, improved appreciation of the many practical benefits of archival tissue chemistry to fisheries and ecosystem-based management will support their increased implementation into routine monitoring.
Graphical abstract
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Cherney MD, Fisher DC, Auchus RJ, Rountrey AN, Selcer P, Shirley EA, Beld SG, Buigues B, Mol D, Boeskorov GG, Vartanyan SL, Tikhonov AN. Testosterone histories from tusks reveal woolly mammoth musth episodes. Nature 2023; 617:533-539. [PMID: 37138076 DOI: 10.1038/s41586-023-06020-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 03/27/2023] [Indexed: 05/05/2023]
Abstract
Hormones in biological media reveal endocrine activity related to development, reproduction, disease and stress on different timescales1. Serum provides immediate circulating concentrations2, whereas various tissues record steroid hormones accumulated over time3,4. Hormones have been studied in keratin, bones and teeth in modern5-8 and ancient contexts9-12; however, the biological significance of such records is subject to ongoing debate10,13-16, and the utility of tooth-associated hormones has not previously been demonstrated. Here we use liquid chromatography with tandem mass spectrometry paired with fine-scale serial sampling to measure steroid hormone concentrations in modern and fossil tusk dentin. An adult male African elephant (Loxodonta africana) tusk shows periodic increases in testosterone that reveal episodes of musth17-19, an annually recurring period of behavioural and physiological changes that enhance mating success20-23. Parallel assessments of a male woolly mammoth (Mammuthus primigenius) tusk show that mammoths also experienced musth. These results set the stage for wide-ranging studies using steroids preserved in dentin to investigate development, reproduction and stress in modern and extinct mammals. Because dentin grows by apposition, resists degradation, and often contains growth lines, teeth have advantages over other tissues that are used as records of endocrine data. Given the low mass of dentin powder required for analytical precision, we anticipate dentin-hormone studies to extend to smaller animals. Thus, in addition to broad applications in zoology and palaeontology, tooth hormone records could support medical, forensic, veterinary and archaeological studies.
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Affiliation(s)
- Michael D Cherney
- Museum of Paleontology, University of Michigan, Ann Arbor, MI, USA.
- Medical School, University of Michigan, Ann Arbor, MI, USA.
| | - Daniel C Fisher
- Museum of Paleontology, University of Michigan, Ann Arbor, MI, USA
- Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
| | | | - Adam N Rountrey
- Museum of Paleontology, University of Michigan, Ann Arbor, MI, USA
| | - Perrin Selcer
- Program in the Environment, University of Michigan, Ann Arbor, MI, USA
| | - Ethan A Shirley
- Museum of Paleontology, University of Michigan, Ann Arbor, MI, USA
- Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Scott G Beld
- Museum of Paleontology, University of Michigan, Ann Arbor, MI, USA
| | | | - Dick Mol
- Natural History Museum, Rotterdam, Netherlands
| | - Gennady G Boeskorov
- Diamond and Precious Metals Geology Institute, Siberian Branch of the Russian Academy of Sciences, St Jean de Luz, Russian Federation
| | - Sergey L Vartanyan
- Laboratory of Cenozoic Geology and Paleogeography, North-east Interdisciplinary Scientific Research Institute, Far-East Branch, Russian Academy of Sciences, Magadan, Russian Federation
| | - Alexei N Tikhonov
- Laboratory of Mammals, Zoological Institute of the Russian Academy of Sciences, St Petersburg, Russian Federation
- Mammoth Museum, North-Eastern Federal University, Yakutsk, Russian Federation
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Majelantle TL, Bennett NC, Ganswindt SB, Hart DW, Ganswindt A. Validation of Enzyme Immunoassays via an Adrenocorticotrophic Stimulation Test for the Non-Invasive Quantification of Stress-Related Hormone Metabolites in Naked Mole-Rats. Animals (Basel) 2023; 13:ani13081424. [PMID: 37106986 PMCID: PMC10135013 DOI: 10.3390/ani13081424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 04/17/2023] [Accepted: 04/19/2023] [Indexed: 04/29/2023] Open
Abstract
Small size in mammals usually restricts long-term, frequent monitoring of endocrine function using plasma as a matrix. Thus, the non-invasive monitoring of hormone metabolite concentrations in excreta may provide an invaluable approach. The aim of the current study was to examine the suitability of enzyme immunoassays (EIAs) for monitoring responses to stressors in the naked mole-rat (Heterocephalus glaber, NMR) using urine and feces as hormone matrices. A saline control administration, and a high- and low-dose adrenocorticotropic hormone (ACTH) challenge were performed on six male and six female disperser morph NMRs. The results revealed that a 5α-pregnane-3β,11β,21-triol-20-one EIA detecting glucocorticoid metabolites (GCMs) with a 5α-3β-11β-diol structure is the most suitable assay for measuring concentrations in male urine samples, whereas an 11-oxoaetiocholanolone EIA detecting GCMs with a 5β-3α-ol-11-one structure appears the most suitable EIA for quantifying GCMs in female urine. An 11-oxoaetiocholanolone EIA detecting 11,17 dioxoandrostanes was the most suitable EIA for quantifying GCMs in the feces of both sexes. There were sex-related differences in response to the high- and low-dose ACTH challenge. We recommend using feces as a more suitable matrix for non-invasive GCM monitoring for NMRs which can be valuable when investigating housing conditions and other welfare aspects.
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Affiliation(s)
- Tshepiso Lesedi Majelantle
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria 0028, South Africa
| | - Nigel Charles Bennett
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria 0028, South Africa
| | - Stefanie Birgit Ganswindt
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria 0028, South Africa
| | - Daniel William Hart
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria 0028, South Africa
| | - Andre Ganswindt
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria 0028, South Africa
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Dillon D, Witten PE, Buck CL. Evaluating Dermal Bone as a Novel Source of Endocrine Information in Ninespine and Threespine Stickleback Fish. Integr Org Biol 2023; 5:obad007. [PMID: 36937455 PMCID: PMC10019498 DOI: 10.1093/iob/obad007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 02/01/2023] [Accepted: 02/27/2023] [Indexed: 03/06/2023] Open
Abstract
Monitoring the physiology of small aquatic and marine teleost fish presents challenges. Blood samples, often the first choice for endocrinologists, can be difficult or even impossible to obtain and alternative matrices currently used for hormone analyses do not occur in fishes (e.g., hair, feathers etc.) or are not easily collected from small aquatic organisms (e.g., urine and feces). Some teleosts, however, have enlarged bony dermal elements that possibly accumulate and store steroid hormones in physiological relevant concentrations. Both threespine stickleback (Gasterosteus aculeatus) and ninespine stickleback (Pungitius pungitius) have a series of external, lateral bony plates, dorsal spines, and a pair of pelvic spines attached to the pelvic girdle. We investigated if cortisol, the primary circulating glucocorticoid in teleosts, could be extracted from stickleback dermal bone and quantified using a commercially available enzyme immunoassay (EIA). We successfully validated a cortisol EIA for dermal bone extracts, determined that cortisol was detectable in both species, and found that dermal bone cortisol levels significantly correlated with cortisol levels in whole body homogenate. Ninespine stickleback had significantly higher dermal bone cortisol concentrations than threespine stickleback and female threespine stickleback tended to have over twice the mean dermal bone cortisol concentration than males. Because both stickleback species are widely used for ecotoxicological studies, using dermal bone as a source of endocrine information, while leaving the body for contaminant, genomic, histological, and stable isotope analyses, could be a powerful and parsimonious tool. Further investigation and physiological validations are necessary to fully understand the utility of this new sample matrix.
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Affiliation(s)
- D Dillon
- Department of Biological Sciences, Northern Arizona University, 617 S. Beaver St., Flagstaff, AZ 86011, USA
| | - P E Witten
- Research Group Evolutionary Developmental Biology, Ghent University, Ledeganckstraat 35, 9000 Ghent, Belgium
| | - C L Buck
- Department of Biological Sciences, Northern Arizona University, 617 S. Beaver St., Flagstaff, AZ 86011, USA
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Atkinson S, Branch TA, Pack AA, Straley JM, Moran JR, Gabriele C, Mashburn KL, Cates K, Yin S. Pregnancy rate and reproductive hormones in humpback whale blubber: Dominant form of progesterone differs during pregnancy. Gen Comp Endocrinol 2023; 330:114151. [PMID: 36341970 DOI: 10.1016/j.ygcen.2022.114151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 10/19/2022] [Accepted: 10/25/2022] [Indexed: 11/04/2022]
Abstract
To better understand reproductive physiology of humpback whales Megaptera novaeangliae that reside in Hawai'i and Alaska, enzyme immunoassays were validated for both progesterone and testosterone in free-ranging and stranded animals (n = 185 biopsies). Concentrations were analyzed between different depths of large segments of blubber taken from skin to muscle layers of stranded female (n = 2, 1 pregnant, 1 non-pregnant) and male (n = 1) whales. Additionally, progesterone metabolites were identified between pregnant (n = 1) and non-pregnant (n = 3) females using high pressure liquid chromatography (HPLC). Progesterone concentrations were compared between juvenile (i.e., sexually immature), lactating, and pregnant females, and male whales, and pregnancy rates of sexually mature females were calculated. Based on replicate samples from ship struck animals collected at 7 depth locations, blubber containing the highest concentration of progesterone was located 1 cm below the skin for females, and the highest concentration of testosterone was in the skin layer of one male whale. HPLC of blubber samples of pregnant and non-pregnant females contain different immunoreactive progesterone metabolites, with the non-pregnant female eluate comprised of a more polar, and possibly conjugated, form of progesterone than the pregnant female. In females, concentrations of progesterone were highest in the blubber of pregnant (n = 28, 28.6 ± 6.9 ng/g), followed by lactating (n = 16, 0.9 ± 0.1 ng/g), and female juvenile (n = 5, 1.0 ± 0.2 ng/g) whales. Progesterone concentrations in male (n = 24, 0.6 ng/g ± 0.1 ng/g) tissues were the lowest all groups, and not different from lactating or juvenile females. Estimated summer season pregnancy rate among sexually mature females from the Hawai'i stock of humpback whales was 0.562 (95 % confidence interval 0.528-0.605). For lactating females, the year-round pregnancy rate was 0.243 (0.09-0.59), and varies depending on the threshold of progesterone assumed for pregnancy in the range between 3.1 and 28.5 ng/g. Our results demonstrate the synergistic value added when combining immunoreactive assays, HPLC, and long-term sighting histories to further knowledge of humpback whale reproductive physiology.
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Affiliation(s)
- S Atkinson
- University of Alaska Fairbanks, College of Fisheries and Ocean Sciences, 17101 Point Lena Loop Road, Juneau, AK 99801, USA.
| | - T A Branch
- University of Washington, School of Aquatic and Fishery Sciences, Box 355020, Washington 98105, USA.
| | - A A Pack
- Departments of Psychology and Biology, University of Hawai'i at Hilo, 200 West Kawili Street, Hilo, HI 96720, USA; The Dolphin Institute, P.O. Box 6279, Hilo, HI 96720, USA.
| | - J M Straley
- University of Alaska Southeast, 1332 Seward Avenue, Sitka, AK 99835, USA.
| | - J R Moran
- National Marine Fisheries Service, Alaska Fisheries Science Center, Ted Stevens Marine Research Institute, 17109 Pt. Lena Loop Road, Juneau, AK 99801, USA.
| | - C Gabriele
- Hawai'i Marine Mammal Consortium, P.O. Box 6107, Kamuela, HI 96743, USA; Glacier Bay National Park & Preserve, P.O. Box 140, Gustavus, AK 99826, USA.
| | - K L Mashburn
- University of Alaska Fairbanks, College of Fisheries and Ocean Sciences, 17101 Point Lena Loop Road, Juneau, AK 99801, USA.
| | - K Cates
- University of Alaska Fairbanks, College of Fisheries and Ocean Sciences, 17101 Point Lena Loop Road, Juneau, AK 99801, USA.
| | - S Yin
- Hawai'i Marine Mammal Consortium, P.O. Box 6107, Kamuela, HI 96743, USA.
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Melica V, Atkinson S, Calambokidis J, Gendron D, Lang A, Scordino J. Naturally stressed? Glucocorticoid profiles in blubber of blue and gray whales in response to life history parameters. MARINE MAMMAL SCIENCE 2022; 38:1524-1548. [PMID: 36619002 PMCID: PMC9815209 DOI: 10.1111/mms.12954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The goal of the present study was to carry out a thorough methodological validation and describe baseline profiles for glucocorticoid hormones (cortisol and corticosterone) in blubber from blue (n = 77) and gray (n = 103) whales from the eastern North Pacific Ocean. For each species, we modelled cortisol and corticosterone concentrations in response to life history parameters (age, sex, reproductive status) and season or geographic location. In blue whales, cortisol concentrations did not vary significantly by age class, sex, or reproductive status, whereas corticosterone was significantly lower in immature than in adult females (p < .001). In gray whales, cortisol concentrations were significantly higher in lactating whales (p < .05), while corticosterone was significantly different between females and males (p = .001) and elevated in calves (p = .003). In gray whales, corticosterone concentrations were significantly lower in males sampled later in the year (August to November) compared to both sexes sampled between March and August (p = .05), but no seasonal trend occurred in blue whales. Our results indicate that glucocorticoid actions vary between species and sex in large whales. Analysis of multiple hormones improves our understanding of the physiology of maintaining metabolic homeostasis or coping with chronic stressors.
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Affiliation(s)
- Valentina Melica
- Fisheries Department, College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Juneau, Alaska
| | - Shannon Atkinson
- Fisheries Department, College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Juneau, Alaska
| | | | - Diane Gendron
- Instituto Politecnico Nacional, Centro Interdisciplinario de Ciencias Marina (IPN-CICIMAR), La Paz, Baja California Sur, Mexico
| | - Aimee Lang
- Ocean Associates Inc., on contract to NOAA Southwest Fisheries Science Center, La Jolla, California
| | - Jonathan Scordino
- Marine Mammal Program, Makah Fisheries Management, Neah Bay, Washington
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14
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Vercauteren M, Ampe B, Devriese L, Moons CPH, Decostere A, Aerts J, Chiers K. Explorative study on scale cortisol accumulation in wild caught common dab (Limanda limanda). BMC Vet Res 2022; 18:324. [PMID: 35996154 PMCID: PMC9394017 DOI: 10.1186/s12917-022-03385-3] [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: 07/17/2020] [Accepted: 07/14/2022] [Indexed: 05/31/2023] Open
Abstract
Background Flatfish live in a diverse marine ecosystem that is changing due to natural variations and anthropogenic influences. These changes can evoke a stress response mainly resulting in production of the glucocorticoid cortisol, which mediates effects on various levels of biological organization. The finding that cortisol accumulates in fish scales, offering a retrospective view on cortisol production, provides opportunities to use this matrix for chronic stress assessment. The present study is the first to gather information on scale cortisol concentration in wild-caught common dab (Limanda limanda), based on a two-pronged approach using (1) field measurements and (2) a laboratory in vivo-study where wild-caught dab were fed by cortisol-spiked feed during 30 or 90 days to demonstrate the possible accumulation of cortisol in the scales and to evaluate its impact on fish health. Results Based on the field measurements, the average scale cortisol concentration in wild-caught fish was 0.0034 ± 0.0046 µg kg−1 scale (n = 67). This indicates that wild common dab is indeed able to incorporate cortisol in the scales. Based on the experimental data, the cortisol-fed fish showed an increased plasma cortisol concentration (80.16 ± 82.58 µg L−1) compared to the control group (4.54 ± 9.57 µg L−1) after 30 days of cortisol feeding. The increase in plasma cortisol concentration was positively correlated with an increased cortisol concentration in the scale after 30 days of cortisol-spiked feeding. This correlation was, however, no longer observed after 90 days of cortisol-spiked feeding. Interestingly, cortisol concentration of the scales on the pigmented side was significantly higher compared to the non-pigmented side. Some health parameters such as epidermal thickness, body condition and Ichthyobodo sp. parasitic infection showed a correlation with scale cortisol concentration after 30 days. Conclusions We have demonstrated that common dab is able to accumulate cortisol in its scales. This seems to occur proportionally to circulating concentrations of plasma cortisol in fish fed with cortisol supplemented feed after 30 days. Supplementary Information The online version contains supplementary material available at 10.1186/s12917-022-03385-3.
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Affiliation(s)
- Maaike Vercauteren
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, Merelbeke, Belgium.
| | - Bart Ampe
- Flanders Research Institute for Agriculture, Fisheries and Food (ILVO), Animal Husbandry, Scheldeweg 68, Melle, Belgium
| | - Lisa Devriese
- Flanders Marine Institute (VLIZ), InnovOcean site, Wandelaarkaai 7, Ostend, Belgium
| | - Christel Palmyre Henri Moons
- Department of Nutrition, Genetics and Ethology, Faculty of Veterinary Medicine, Ghent University, Heidestraat 19, Merelbeke, Belgium
| | - Annemie Decostere
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, Merelbeke, Belgium
| | - Johan Aerts
- Stress Physiology Research GroupFlanders Research Institute for Agricultural and Fisheries and FoodDepartment of Biology, Faculty of Sciences, Animal Sciences Unit, Ghent University, Wetenschapspark 1, Ostend, Belgium
| | - Koen Chiers
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, Merelbeke, Belgium
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Roffler GH, Karpovich S, Charapata P, Keogh MJ. Validation and measurement of physiological stress and reproductive hormones in wolf hair and claws. WILDLIFE SOC B 2022. [DOI: 10.1002/wsb.1330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Gretchen H. Roffler
- Alaska Department of Fish and Game Division of Wildlife Conservation 801 3rd Street Douglas AK 99824 USA
| | - Shawna Karpovich
- Alaska Department of Fish and Game Division of Wildlife Conservation 1300 College, Road Fairbanks AK 99701 USA
| | - Patrick Charapata
- Alaska Department of Fish and Game Division of Wildlife Conservation 1300 College, Road Fairbanks AK 99701 USA
| | - Mandy J. Keogh
- Alaska Department of Fish and Game Division of Wildlife Conservation 801 3rd Street Douglas AK 99824 USA
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16
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Lowe CL, Hunt KE, Neilson JL, Gabriele CM, Teerlink SS, Buck CL. Reproductive Steroid Hormone Patterns in Baleen of Two Pregnant Humpback Whales (Megaptera Novaeangliae). Integr Comp Biol 2022; 62:152-163. [PMID: 35671163 DOI: 10.1093/icb/icac070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 05/16/2022] [Accepted: 05/19/2022] [Indexed: 11/14/2022] Open
Abstract
Understanding reproductive physiology in mysticetes has been slowed by the lack of repeated samples from individuals. Analysis of humpback whale baleen enables retrospective hormone analysis within individuals dating back three to five years before death. Using this method, we investigated differences in four steroid hormones involved in reproduction and mating during confirmed pregnant and non-pregnant periods in two female humpback whales (Megaptera novaeangliae) with known reproductive histories based on sightings and necropsy data. Cortisol, corticosterone, testosterone and estradiol concentrations were determined via enzyme immunoassay using subsamples of each baleen plate at 2 cm intervals. There were no significant differences in cortisol or corticosterone during pregnancy when compared to non-pregnancy (inter-calving interval), but there were significant differences between the two whales in average glucocorticoid concentrations, with the younger whale showing higher values overall. For testosterone, levels for the younger female peaked at parturition in one pregnancy, but also had spikes during nonpregnancy. The older female had three large spikes in testosterone, one of which was associated with parturition. Estradiol had large fluctuations in both whales but had generally lower concentrations during non-pregnancy than during pregnancy. There were peaks in estradiol before each pregnancy, possibly coinciding with ovulation, and peaks coinciding with the month of parturition. Both estradiol and testosterone could be useful for determining ovulation or impending birth. Using baleen to investigate retrospective steroid hormone profiles can be used for elucidating long-term patterns of physiological change during gestation.
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Affiliation(s)
- Carley L Lowe
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011USA
| | - Kathleen E Hunt
- Department of Biology, Smithsonian-Mason School of Conservation & George Mason University, Front Royal, VI 22630USA
| | - Janet L Neilson
- Humpback Whale Monitoring Program, Glacier Bay National Park & Preserve, Gustavus, AK 99826USA
| | - Christine M Gabriele
- Humpback Whale Monitoring Program, Glacier Bay National Park & Preserve, Gustavus, AK 99826USA
| | | | - C Loren Buck
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011USA
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17
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Hunt KE, Buck CL, Ferguson SH, Fernández Ajo A, Heide-Jørgensen MP, Matthews CJD. Male Bowhead Whale Reproductive Histories Inferred from Baleen Testosterone and Stable Isotopes. Integr Org Biol 2022; 4:obac014. [PMID: 35617113 PMCID: PMC9125798 DOI: 10.1093/iob/obac014] [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] [Indexed: 11/14/2022] Open
Abstract
Synopsis
Male mammals of seasonally reproducing species typically have annual testosterone (T) cycles, with T usually peaking during the breeding season, but occurrence of such cycles in male mysticete whales has been difficult to confirm. Baleen, a keratinized filter-feeding apparatus of mysticetes, incorporates hormones as it grows, such that a single baleen plate can record years of endocrine history with sufficient temporal resolution to discern seasonal patterns. We analyzed patterns of T every 2 cm across the full length of baleen plates from nine male bowhead whales (Balaena mysticetus) to investigate occurrence and regularity of T cycles and potential inferences about timing of breeding season, sexual maturation, and reproductive senescence. Baleen specimens ranged from 181–330 cm in length, representing an estimated 11 years (smallest whale) to 22 years (largest whale) of continuous baleen growth, as indicated by annual cycles in stable isotopes. All baleen specimens contained regularly spaced areas of high T content (T peaks) confirmed by time series analysis to be cyclic, with periods matching annual stable isotope cycles of the same individuals. In 8 of the 9 whales, T peaks preceded putative summer isotope peaks by a mean of 2.8 months, suggesting a mating season in late winter / early spring. The only exception to this pattern was the smallest and youngest male, which had T peaks synchronous with isotope peaks. This smallest, youngest whale also did not have T peaks in the first half of the plate, suggesting initiation of T cycling during the period of baleen growth. Linear mixed effect models suggest that whale age influences T concentrations, with the two largest and oldest males exhibiting a dramatic decline in T peak concentration across the period of baleen growth. Overall, these patterns are consistent with onset of sexual maturity in younger males and possible reproductive senescence in older males. We conclude that adult male bowheads undergo annual T cycles, and that analyses of T in baleen may enable investigation of reproductive seasonality, timing of the breeding season, and life history of male whales.
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Affiliation(s)
- Kathleen E Hunt
- Smithsonian-Mason School of Conservation & Department of Biology, George Mason University, 1500 Remount Rd, Front Royal, VA 22630, USA
| | - C Loren Buck
- Department of Biological Sciences, Northern Arizona University, 617 S. Beaver St., Flagstaff, AZ 86011, USA
| | - Steven H Ferguson
- Fisheries and Oceans Canada, Arctic Aquatic Research Division, 501 University Crescent, Winnipeg, MB R3T 2N6, Canada
| | - Alejandro Fernández Ajo
- Marine Mammal Institute, Fisheries and Wildlife Department, Oregon State University, Newport, OR 97365, USA
| | | | - Cory J D Matthews
- Fisheries and Oceans Canada, Arctic Aquatic Research Division, 501 University Crescent, Winnipeg, MB R3T 2N6, Canada
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18
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Fernández Ajó A, Hunt KE, Dillon D, Uhart M, Sironi M, Rowntree V, Loren Buck C. Optimizing hormone extraction protocols for whale baleen: Tackling questions of solvent:sample ratio and variation. Gen Comp Endocrinol 2022; 315:113828. [PMID: 34058189 DOI: 10.1016/j.ygcen.2021.113828] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 05/25/2021] [Indexed: 12/19/2022]
Abstract
Obtaining endocrine data from alternative sample types such as baleen and other keratinized tissues has proven a valuable tool to investigate reproductive and stress physiology via steroid hormone quantification, and metabolic stress via thyroid hormone quantification in whales and other vertebrates. These alternative sample types provide an integrated measure of plasma levels over the period that the structure was growing, thus capturing months or even years of an individual's endocrine history. Additionally, their robust and stable keratin matrix allows such samples to be stored for years to decades, enabling the analysis and comparison of endocrine patterns from past and modern populations. However, the extraction and analysis of hormones from baleen and other keratinized tissues remains novel and requires both biological and analytical validations to ensure the method fulfills the requirements for its intended use. We utilized baleen recovered at necropsy from southern right whales (Eubalaena australis) that died at Península Valdés, Argentina, using a commercially available progesterone enzyme immunoassay (EIA) to address two methodological questions: 1) what is the minimum sample mass required to reliably quantify hormone content of baleen samples analyzed with commercially available EIAs, and 2) what is the optimal ratio of solvent volume to sample mass, i.e., the ratio that yields the maximum amount of hormone with high accuracy and low variability between replicates. We concluded that masses of at least 20 mg should be used whenever possible, and extraction is best performed using an 80:1 ratio of solvent to sample (volume of solvent to sample mass; μl:mg). These results can help researchers to make informed methodological decisions when using a destructive extraction method with rare or unique specimens.
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Affiliation(s)
- Alejandro Fernández Ajó
- Department of Biological Sciences, Northern Arizona University, 617 S. Beaver St., PO Box 5640, Flagstaff, AZ 86011, USA; Instituto de Conservación de Ballenas, Capital Federal, O'Higgins 4380, Ciudad Autónoma de Buenos Aires 1429, Argentina.
| | - Kathleen E Hunt
- George Mason University & Smithsonian-Mason School of Conservation, 1500 Remount Rd, Front Royal, VA 22630, USA
| | - Danielle Dillon
- Department of Biological Sciences, Northern Arizona University, 617 S. Beaver St., PO Box 5640, Flagstaff, AZ 86011, USA
| | - Marcela Uhart
- Southern Right Whale Health Monitoring Program, Los Alerces 3376, Puerto Madryn, Chubut 9120, Argentina; Wildlife Health Center, School of Veterinary Medicine, University of California, 1089 Veterinary Medicine Drive, VM3B Ground Floor, Davis, CA 95616, USA
| | - Mariano Sironi
- Instituto de Conservación de Ballenas, Capital Federal, O'Higgins 4380, Ciudad Autónoma de Buenos Aires 1429, Argentina; Facultad de Ciencias Exactas, Físicas y Naturales (FCEFyN), Universidad Nacional de Córdoba, Av. Vélez Sársfield 299, Córdoba 5000, Argentina
| | - Victoria Rowntree
- Instituto de Conservación de Ballenas, Capital Federal, O'Higgins 4380, Ciudad Autónoma de Buenos Aires 1429, Argentina; Wildlife Health Center, School of Veterinary Medicine, University of California, 1089 Veterinary Medicine Drive, VM3B Ground Floor, Davis, CA 95616, USA; Department of Biology, University of Utah, 257 South 1400 East University of Utah, Salt Lake City, UT 84112, USA; Ocean Alliance/Whale Conservation Institute, 32 Horton St, Gloucester, MA 01930, USA
| | - C Loren Buck
- Department of Biological Sciences, Northern Arizona University, 617 S. Beaver St., PO Box 5640, Flagstaff, AZ 86011, USA
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Riekenberg PM, Camalich J, Svensson E, IJsseldijk LL, Brasseur SMJM, Witbaard R, Leopold MF, Rebolledo EB, Middelburg JJ, van der Meer MTJ, Sinninghe Damsté JS, Schouten S. Reconstructing the diet, trophic level and migration pattern of mysticete whales based on baleen isotopic composition. ROYAL SOCIETY OPEN SCIENCE 2021; 8:210949. [PMID: 34909214 PMCID: PMC8652277 DOI: 10.1098/rsos.210949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 10/28/2021] [Indexed: 06/14/2023]
Abstract
Baleen from mysticete whales is a well-preserved proteinaceous material that can be used to identify migrations and feeding habits for species whose migration pathways are unknown. Analysis of δ13C and δ15N values from bulk baleen have been used to infer migration patterns for individuals. However, this approach has fallen short of identifying migrations between regions as it is difficult to determine variations in isotopic shifts without temporal sampling of prey items. Here, we apply analysis of δ15N values of amino acids to five baleen plates belonging to three species, revealing novel insights on trophic position, metabolic state and migration between regions. Humpback and minke whales had higher reconstructed trophic levels than fin whales (3.7-3.8 versus 3-3.2, respectively) as expected due to different feeding specialization. Isotopic niche areas between baleen minima and maxima were well separated, indicating regional resource use for individuals during migration that aligned with isotopic gradients in Atlantic Ocean particulate organic matter. Phenylanine δ15N values confirmed regional separation between the niche areas for two fin whales as migrations occurred and elevated glycine and threonine δ15N values suggested physiological changes due to fasting. Simultaneous resolution of trophic level and physiological changes allow for identification of regional migrations in mysticetes.
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Affiliation(s)
- Philip M. Riekenberg
- Department of Marine Microbiology and Biogeochemistry, NIOZ Royal Netherlands Institute for Sea Research, PO Box 59, Den Hoorn 1790AB, The Netherlands
| | - Jaime Camalich
- Department of Marine Microbiology and Biogeochemistry, NIOZ Royal Netherlands Institute for Sea Research, PO Box 59, Den Hoorn 1790AB, The Netherlands
| | - Elisabeth Svensson
- Department of Marine Microbiology and Biogeochemistry, NIOZ Royal Netherlands Institute for Sea Research, PO Box 59, Den Hoorn 1790AB, The Netherlands
| | - Lonneke L. IJsseldijk
- Division of Pathology, Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3854 CL Utrecht, The Netherlands
| | - Sophie M. J. M. Brasseur
- Wageningen Marine Research, Wageningen University and Research, PO Box 57, 1780 AB Den Helder, The Netherlands
| | - Rob Witbaard
- Department of Estuarine and Delta Systems, NIOZ Royal Netherlands Institute for Sea Research, and Utrecht University, PO Box 140, 4400 AC Yerseke, The Netherlands
| | - Mardik F. Leopold
- Wageningen Marine Research, Wageningen University and Research, PO Box 57, 1780 AB Den Helder, The Netherlands
| | - Elisa Bravo Rebolledo
- Wageningen Marine Research, Wageningen University and Research, PO Box 57, 1780 AB Den Helder, The Netherlands
| | - Jack J. Middelburg
- Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Princetonlaan 8a, 3584 CB Utrecht, The Netherlands
| | - Marcel T. J. van der Meer
- Department of Marine Microbiology and Biogeochemistry, NIOZ Royal Netherlands Institute for Sea Research, PO Box 59, Den Hoorn 1790AB, The Netherlands
| | - Jaap S. Sinninghe Damsté
- Department of Marine Microbiology and Biogeochemistry, NIOZ Royal Netherlands Institute for Sea Research, PO Box 59, Den Hoorn 1790AB, The Netherlands
- Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Princetonlaan 8a, 3584 CB Utrecht, The Netherlands
| | - Stefan Schouten
- Department of Marine Microbiology and Biogeochemistry, NIOZ Royal Netherlands Institute for Sea Research, PO Box 59, Den Hoorn 1790AB, The Netherlands
- Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Princetonlaan 8a, 3584 CB Utrecht, The Netherlands
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20
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Seasonal changes in steroid and thyroid hormone content in shed skins of the tegu lizard Salvator merianae. J Comp Physiol B 2021; 192:127-139. [PMID: 34379176 DOI: 10.1007/s00360-021-01397-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 06/30/2021] [Accepted: 08/02/2021] [Indexed: 10/20/2022]
Abstract
Sampling blood for endocrine analysis from some species may not be practical or ethical. Quantification of hormones extracted from nontypical sample types, such as keratinized tissues, offers a less invasive alternative to the traditional collection and analysis of blood. Here, we aimed to validate assays by using parallelism and accuracy tests for quantification of testosterone, corticosterone, progesterone, and triiodothyronine (T3) in shed skins of tegu lizards. We assessed whether hormone content of sheds varied across one year similar to what was previously detected in plasma samples. In addition, we aimed to identify the phase relationship between hormone levels of shed skin and plasma levels obtained from the same animals. High frequency of shedding occurred during the active season for tegus (spring/summer), while shedding ceased during hibernation (winter). All hormones measured in shed skins exhibited seasonal changes in concentration. Levels of testosterone in shed skins of male tegus correlated positively with plasma testosterone levels, while corticosterone in both males and females exhibited an inverse relationship between sample types for the same month of collection. An inverse relationship was found when accounting for a lag time of 3 and 4 months between sheds and plasma testosterone. These results indicate that endocrine content of sheds may be confounded by factors (i.e., seasons, environmental temperature, thermoregulatory behavior, among others) that affect frequency of molting, skin blood perfusion, and therefore hormone transfer from the bloodstream and deposition in sheds of squamates.
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21
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Dillon D, Fernández Ajó A, Hunt KE, Buck CL. Investigation of keratinase digestion to improve steroid hormone extraction from diverse keratinous tissues. Gen Comp Endocrinol 2021; 309:113795. [PMID: 33891932 DOI: 10.1016/j.ygcen.2021.113795] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 04/16/2021] [Accepted: 04/17/2021] [Indexed: 12/29/2022]
Abstract
Monitoring the physiology of wild populations presents many technical challenges. Blood samples, long the gold standard of wildlife endocrinology studies, cannot always be obtained. The validation and use of non-plasma samples to obtain hormone data have greatly improved access to more integrated information about an organism's physiological state. Keratinous tissues like skin, hair, nails, feathers, or baleen store steroid hormones in physiologically relevant concentrations, are stable across decades, and can be used to retrospectively infer physiological state at prior points in time. Most protocols for steroid extraction employ physical pulverization or cutting of the sample, followed by mixing with a solvent. Such methods do produce repeatable and useful data, but low hormone yield and detectability issues can complicate research on small or rare samples. We investigated the use of keratinase, an enzyme that breaks down keratin, to improve the extraction and yield of corticosterone from vertebrate keratin tissues. Corticosterone content of keratinase-digested extracts were compared to non-keratinase extracts for baleen from three species of whale (blue, Balaenoptera musculus; bowhead, Balaena mysticetus; southern right, SRW; Eubalaena australis), shed skin from two reptiles (tegu lizard, Salvator merianae; narrow-headed garter snake, Thamnophis rufipunctatus), hair from arctic ground squirrel (AGS; Urocitellus parryii), feathers from Purple Martins (PUMA; Progne subis), and spines from the short-beaked echidna (Tachyglossus aculeatus). We tested four starting masses (10, 25, 50, 100 mg) for each sample; digestion was most complete in the 10 and 25 mg samples. A corticosterone enzyme immunoassay (EIA) was validated for all keratinase-digested extracts. In all sample types except shed skin from reptiles, keratinase digestion improved hormone yield, with PUMA feathers and blue whale baleen having the greatest increase in apparent corticosterone content (100% and 66% more hormone, respectively). The reptilian shed skin samples did not benefit from keratinase digestion, actually yielding less hormone than controls. With further optimization and refinement, keratinase digestion could greatly improve yield of steroid hormones from various wildlife epidermal tissue types, allowing more efficient use of samples and ultimately improving understanding of the endocrine physiology of wild populations.
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Affiliation(s)
- Danielle Dillon
- Department of Biological Sciences, Northern Arizona University, 617 S. Beaver St., Flagstaff, AZ 86011, USA.
| | - Alejandro Fernández Ajó
- Department of Biological Sciences, Northern Arizona University, 617 S. Beaver St., Flagstaff, AZ 86011, USA; Instituto de Conservación de Ballenas, Capital Federal, O'Higgins 4380, Ciudad Autónoma de Buenos Aires 1429, Argentina
| | - Kathleen E Hunt
- Smithsonian-Mason School of Conservation & Department of Biology, George Mason University, 1500 Remount Rd, Front Royal, VA 22630, USA
| | - C Loren Buck
- Department of Biological Sciences, Northern Arizona University, 617 S. Beaver St., Flagstaff, AZ 86011, USA
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22
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Lowe CL, Hunt KE, Rogers MC, Neilson JL, Robbins J, Gabriele CM, Teerlink SS, Seton R, Buck CL. Multi-year progesterone profiles during pregnancy in baleen of humpback whales ( Megaptera novaeangliae). CONSERVATION PHYSIOLOGY 2021; 9:coab059. [PMID: 34745632 PMCID: PMC8567847 DOI: 10.1093/conphys/coab059] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 04/27/2021] [Accepted: 07/13/2021] [Indexed: 05/27/2023]
Abstract
Understanding calving rates of wild whale populations is critically important for management and conservation. Reproduction of humpback whales (Megaptera novaeangliae) is difficult to monitor and, even with long-term sighting studies, basic physiological information such as pregnancy rates and calving intervals remain poorly understood in many populations. We hypothesized that pregnant whales have sustained elevations in baleen progesterone that temporally correlate with gestation. To test this hypothesis, baleen progesterone profiles from two adult female North Pacific humpbacks, both with extensive sighting records and documented pregnancies, were compared to those of a nulliparous female (adult female never seen with a calf) and a juvenile male. Baleen specimens recovered during necropsy were subsampled every 2 cm from the base to the tip of the plate, with each interval representing 30-45 days of growth. Homogenized baleen powder was assayed for progesterone using enzyme immunoassays. The date of growth of each sampling location on the baleen plate was estimated based on stable isotope analysis of annual δ15N cycles. Progesterone profiles from both pregnant whales showed sustained high progesterone content (>350 ng/g) in areas corresponding to known pregnancies, inferred from calf sightings and post-mortem data. The younger female, estimated to be 13 years old, had higher progesterone during pregnancy than the 44.5 year old, but levels during non-pregnancy were similar. The nulliparous female and the male had low progesterone throughout their baleen plates. Baleen hormone analysis can determine how progesterone concentrations change throughout gestation and has potential for estimating age at first reproduction, pregnancy intervals, failed pregnancies and early calf mortality. Understanding rates of calving and current and historic reproductive patterns in humpbacks is vital to continuing conservation measures in this species.
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Affiliation(s)
- Carley L Lowe
- Department of Biological Sciences, Northern Arizona
University, Flagstaff, AZ 86011, USA
| | - Kathleen E Hunt
- Department of Biology, George Mason University and
Smithsonian-Mason School of Conservation, Front Royal, VA 22630,
USA
| | - Matthew C Rogers
- Alaska Fisheries Science Center Auke Bay Laboratories, NOAA,
National Marine Fisheries Service, Juneau, AK 99801, USA
| | - Janet L Neilson
- Humpback Whale Monitoring Program, Glacier Bay National Park
and Preserve, Gustavus, AK 99826, USA
| | - Jooke Robbins
- Center for Coastal Studies, Provincetown, MA
02657, USA
| | - Christine M Gabriele
- Humpback Whale Monitoring Program, Glacier Bay National Park
and Preserve, Gustavus, AK 99826, USA
| | | | | | - C Loren Buck
- Department of Biological Sciences, Northern Arizona
University, Flagstaff, AZ 86011, USA
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23
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Blecher AS, Ganswindt A, Scheun J. Scales of our lives: Sex identification of Temminck's pangolin (Smutsia temminckii) using scales retrieved out of the illegal wildlife trade. Gen Comp Endocrinol 2021; 308:113782. [PMID: 33862053 DOI: 10.1016/j.ygcen.2021.113782] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 02/24/2021] [Accepted: 04/09/2021] [Indexed: 01/09/2023]
Abstract
Pangolins are the most trafficked wild mammals, with their scales in high demand. Scales are often the only part of the animal confiscated from the trade, but they represent accessible material for forensic investigations, including for sexing. This study aimed to develop a sexing tool for Temminck's pangolin, using scales for hormone quantification. Scales from males and females were liquidised using keratinase and the resulting suspension analysed for progestagen and androgen metabolite (scPM and scAM) concentrations. Scale PM and scAM concentrations were compared between sexes, while overall median values for scPM and scAM, as well as a ratio of scPM to scAM (P/A) were used as boundary values for sex identification. Neither scPM nor scAM concentrations were significantly different between the sexes and concentrations of a juvenile and sub-adult male overlapped with females, possibly indicating later sexual maturity in males. Boundary values for scAM concentrations and the P/A ratio predicted sex with 100% accuracy for females and 78% for males, while the accuracies for the scPM boundary value were lower. When only adult individuals are considered, scAM and P/A ratio boundaries are 100% accurate for both sexes. Therefore, scale hormone ratios show promise as a sex identification tool for Temminck's pangolin, particularly applicable in forensic investigations on the pangolin trade.
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Affiliation(s)
- Arantxa S Blecher
- Mammal Research Institute, Department of Zoology and Entomology, Faculty of Natural and Agricultural Sciences, University of Pretoria, South Africa.
| | - André Ganswindt
- Mammal Research Institute, Department of Zoology and Entomology, Faculty of Natural and Agricultural Sciences, University of Pretoria, South Africa; Biodiversity Research Services, National Zoological Gardens, South Africa
| | - Juan Scheun
- Mammal Research Institute, Department of Zoology and Entomology, Faculty of Natural and Agricultural Sciences, University of Pretoria, South Africa; Biodiversity Research Services, National Zoological Gardens, South Africa; Department of Life and Consumer Sciences, University of South Africa, South Africa
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24
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Charapata P, Horstmann L, Misarti N. Steroid hormones in Pacific walrus bones collected over three millennia indicate physiological responses to changes in estimated population size and the environment. CONSERVATION PHYSIOLOGY 2021; 9:coaa135. [PMID: 33537147 PMCID: PMC7836870 DOI: 10.1093/conphys/coaa135] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 11/10/2020] [Accepted: 12/15/2020] [Indexed: 05/15/2023]
Abstract
The Pacific walrus (Odobenus rosmarus divergens) is an iconic Arctic marine mammal and an important resource to many Alaska Natives. A decrease in sea ice habitat and unknown population numbers has led to concern of the long-term future health of the walrus population. There is currently no clear understanding of how walrus physiology might be affected by a changing Arctic ecosystem. In this study, steroid hormone concentrations (progesterone, testosterone, cortisol and estradiol) were analysed in walrus bones collected during archaeological [3585-200 calendar years before present (BP)], historical [1880-2006 common era (CE)] and modern (2014-2016 CE) time periods, representing ~ 3651 years, to track changes in reproductive activity and cortisol concentrations (biomarker of stress) over time. Our results show that modern walrus samples have similar cortisol concentrations (median = 43.97 ± standard deviation 904.38 ng/g lipid) to archaeological walruses (38.94 ± 296.17 ng/g lipid, P = 0.75). Cortisol concentrations were weakly correlated with a 15-year average September Chukchi Sea ice cover (P = 0.002, 0.02, r 2 = 0.09, 0.04, for females and males, respectively), indicating a possible physiological resiliency to sea ice recession in the Arctic. All steroid hormones had significant negative correlations with mean walrus population estimates from 1960 to 2016 (P < 0.001). Progesterone in females and testosterone in males exhibited significant correlations with average September Chukchi Sea ice cover for years 1880-2016 (P < 0.001 for both, r2 = 0.34, 0.22, respectively). Modern walruses had significantly lower (P = < 0.001) reproductive hormone concentrations compared with historic walruses during times of rapid population increase, indicative of a population possibly at carrying capacity. This is the first study to apply bone as a tool to monitor long-term changes in hormones that may be associated with changes in walrus population size and sea ice cover.
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Affiliation(s)
- Patrick Charapata
- College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, PO Box 757220, Fairbanks, AK 99775, USA
- Department of Biology, Baylor University, One Bear Place, Waco, TX 76706, USA
| | - Lara Horstmann
- College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, PO Box 757220, Fairbanks, AK 99775, USA
| | - Nicole Misarti
- Water and Environmental Research Center, University of Alaska Fairbanks, PO Box 755910, Fairbanks, AK 99775, USA
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25
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Blecher AS, Scheun J, Ganswindt A. Degradation of Temminck's pangolin ( Smutsia temminckii) scales with a keratinase for extraction of reproductive steroid hormones. MethodsX 2021; 8:101229. [PMID: 34434752 PMCID: PMC8374191 DOI: 10.1016/j.mex.2021.101229] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 01/08/2021] [Indexed: 01/07/2023] Open
Abstract
Hormone monitoring in keratinous tissues has become increasingly popular. The insoluble keratin materials are generally pulverised before hormone extraction; however, this is difficult for thicker keratin structures like baleen plates or hooves. A new method, involving the use of keratinase, allows enzymatic digestion of keratin and hormone analysis in the resulting suspension. Pangolins are unique mammals covered in keratinous scales, which are one of the reasons these animals are extensively trafficked. This study aimed to investigate the suitability of Temminck's pangolin scales as hormone matrix for quantifying reproductive steroids. A protocol was developed to digest scales with a keratinase before measuring hormone concentrations. This method can be used to investigate the reproductive endocrinology of Temminck's pangolins but may also be extended to the other extant pangolin species.•Keratinase digests Temminck's pangolin scales and reproductive steroid metabolite concentrations are measurable in the resulting suspension.•Isopropanol is an ideal washing solvent for scales to remove surface contaminants and scale sample mass should be standardised to allow comparisons.•Any section of a scale and scales from any pangolin body region can be used as samples for hormone quantification.
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Affiliation(s)
- Arantxa S. Blecher
- Mammal Research Institute, Department of Zoology and Entomology, Faculty of Natural and Agricultural Sciences, University of Pretoria, South Africa
| | - Juan Scheun
- Mammal Research Institute, Department of Zoology and Entomology, Faculty of Natural and Agricultural Sciences, University of Pretoria, South Africa
- Biodiversity Research Services, National Zoological Gardens, South Africa
- Department of Life and Consumer Sciences, University of South Africa, South Africa
| | - André Ganswindt
- Mammal Research Institute, Department of Zoology and Entomology, Faculty of Natural and Agricultural Sciences, University of Pretoria, South Africa
- Biodiversity Research Services, National Zoological Gardens, South Africa
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26
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Keogh MJ, Charapata P, Fadely BS, Zeppelin T, Rea L, Waite JN, Burkanov V, Marshall C, Jones A, Sprowls C, Wooller MJ. Whiskers as a novel tissue for tracking reproductive and stress-related hormones in North Pacific otariid pinnipeds. CONSERVATION PHYSIOLOGY 2021; 9:coaa134. [PMID: 33489238 PMCID: PMC7808128 DOI: 10.1093/conphys/coaa134] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 11/07/2020] [Accepted: 12/15/2020] [Indexed: 05/30/2023]
Abstract
Keratinized tissues, including whiskers, are ideal for acquiring a record of physiological parameters. Most tissues provide a snapshot of physiological status; however, whiskers may support longitudinal sampling for reproductive and stress-related hormones, if hormones are incorporated as whiskers grow and concentrations change with physiological state. Whiskers from female Steller sea lions (Eumetopias jubatus) and northern fur seals (Callorhinus ursinus) were serially sectioned and pulverized and steroid hormones were extracted. Standard methods were used to validate enzyme immunoassay kits for cortisol, progesterone, 17β-estradiol and testosterone. All hormones were measurable in whisker segments from both species with progesterone concentrations showing cyclical patterns, which appear to signify previous pregnancies or luteal phases. Yearly progesterone concentrations were greater in years a pup was produced compared with years when no pup was observed. Free-ranging female Steller sea lions had reproductive rates between 0 and 1.0 (0.53 ± 0.33, n = 12) using a yearly progesterone concentration of 30 pg/mg or greater to classify a reproductive year as producing a pup and below 30 pg/mg as non-reproductive. Cortisol concentrations were greater near the root and rapidly declined, lacking any obvious patterns, throughout the rest of the whisker. Progesterone and testosterone concentrations were able to help determine sex of unknown individuals. Immunohistochemistry revealed that steroid hormones most likely do not leach out of whiskers based on the deposition patterns of progesterone and cortisol being present throughout the whisker length. Overall, measuring steroid hormones in whiskers can reveal individual reproductive histories over multiple years in sea lions and fur seals. Cyclical patterns of δ15N were useful for identifying periods of up to ~10 years of growth within whiskers, and measuring both stable isotopes and hormones may be useful for differentiating periods of active gestation from diapause and potentially track multi-year reproductive histories of female otariids.
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Affiliation(s)
- Mandy J Keogh
- Division of Wildlife Conservation, Alaska Department of Fish and Game, P.O. Box 110024 Douglas, AK 99811-0024, USA
| | - Patrick Charapata
- Division of Wildlife Conservation, Alaska Department of Fish and Game, 1300 College Road, Fairbanks, AK 99701, USA
- Biology Department, Baylor University, One Bear Place #97388, Waco, TX 76798, USA
| | - Brian S Fadely
- Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 7600 Sand Point Way NE, Seattle, WA 98115, USA
| | - Tonya Zeppelin
- Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 7600 Sand Point Way NE, Seattle, WA 98115, USA
| | - Lorrie Rea
- Water and Environmental Research Center, Institute of Northern Engineering, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
| | - Jason N Waite
- Division of Wildlife Conservation, Alaska Department of Fish and Game, P.O. Box 110024 Douglas, AK 99811-0024, USA
| | - Vladimir Burkanov
- Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 7600 Sand Point Way NE, Seattle, WA 98115, USA
- Kamchatka Branch of the Pacific Geographical Institute Far East Branch, Russian Academy of Sciences, Petropavlovsk-Kamchatsky 683000, Russia
| | - Chris Marshall
- Department of Marine Biology, Texas A&M University, Galveston Campus, Galveston, TX 77553, USA
- Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, TX 77843, USA
| | - Aubree Jones
- Department of Marine Biology, Texas A&M University, Galveston Campus, Galveston, TX 77553, USA
| | - Caitlin Sprowls
- Department of Marine Biology, Texas A&M University, Galveston Campus, Galveston, TX 77553, USA
| | - Matthew J Wooller
- Water and Environmental Research Center, Institute of Northern Engineering, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
- Alaska Stable Isotope Facility, Water and Environmental Research Center, Institute of Northern Engineering, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
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27
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Graham KM, Burgess EA, Rolland RM. Stress and reproductive events detected in North Atlantic right whale blubber using a simplified hormone extraction protocol. CONSERVATION PHYSIOLOGY 2021; 9:coaa133. [PMID: 33489237 PMCID: PMC7808127 DOI: 10.1093/conphys/coaa133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 10/16/2020] [Accepted: 12/14/2020] [Indexed: 06/12/2023]
Abstract
As studies quantifying steroid hormones in marine mammal blubber progress, methodological refinements may improve the utility and consistency of blubber hormone measurements. This study advances blubber extraction methodologies by testing a simplified extraction protocol that reduces time and complexity compared to a protocol widely used in cetacean blubber studies. Using blubber samples archived from remote biopsy (n = 21 live whales) and necropsy collection (n = 7 dead whales) of North Atlantic right whales (NARW; Eubalaena glacialis) of known life history states, we performed analytical and biological validations to assess the feasibility of measuring reproductive (testosterone, progesterone) and glucocorticoid (cortisol) hormones in blubber via enzyme immunoassay following the simplified extraction. Analytical validations (parallelism, accuracy, extraction efficiency, repeatability) showed the simplified extraction produced similar results to the extended protocol, offering a more efficient and consistent technique. In live, apparently healthy whales, blubber testosterone concentrations (mean ± SE) were significantly higher in males (2.02 ± 0.36 ng/g) compared to females (0.81 ± 0.15 ng/g). Blubber progesterone was highest in a confirmed pregnant female (60.3 ng/g), which was 12-fold greater than the mean concentration of non-pregnant females (4.56 ± 0.88 ng/g). Blubber cortisol concentrations in whales that died from anthropogenic causes averaged 5.31 ± 2.28 ng/g, whereas most live, healthy whales had cortisol values below 1 ng/g. Among living whales, a whale actively entangled in fishing gear had the highest blubber cortisol measurement (3.51 ng/g), exhibiting levels similar to whales that died from acute entanglement (2.88 ± 0.42 ng/g). Overall, the highest blubber cortisol concentration (18.0 ng/g) was measured in a dead whale with a severe chronic entanglement, approximately 30-fold greater than mean blubber cortisol of apparently healthy whales (0.58 ± 0.11 ng/g). The methodological approach presented here provides a reference for researchers interested in an alternative, streamlined technique for hormone extraction of cetacean blubber and contributes to the diverse tool set for stress and reproductive assessments of endangered NARWs.
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Affiliation(s)
- Katherine M Graham
- Anderson Cabot Center for Ocean Life at the New England Aquarium, Central Wharf, Boston, MA 02110, USA
| | - Elizabeth A Burgess
- Anderson Cabot Center for Ocean Life at the New England Aquarium, Central Wharf, Boston, MA 02110, USA
| | - Rosalind M Rolland
- Anderson Cabot Center for Ocean Life at the New England Aquarium, Central Wharf, Boston, MA 02110, USA
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28
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Crain DD, Karpovich SA, Quakenbush L, Polasek L. Using claws to compare reproduction, stress and diet of female bearded and ringed seals in the Bering and Chukchi seas, Alaska, between 1953-1968 and 1998-2014. CONSERVATION PHYSIOLOGY 2021; 9:coaa115. [PMID: 33442472 PMCID: PMC7786451 DOI: 10.1093/conphys/coaa115] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/27/2020] [Accepted: 11/20/2020] [Indexed: 05/08/2023]
Abstract
Rapid climate warming is decreasing sea ice thickness, extent and duration. Marine mammals such as bearded (Erignathus barbatus) and ringed (Pusa hispida) seals, which use sea ice for pupping, molting and resting, may be negatively affected. Claws from bearded and ringed seals store up to 14 and 12 years of sequential analyte data, respectively. These data can be used to compare reproduction, stress and diet across decades. In this study, we compare progesterone, cortisol and carbon and nitrogen stable isotopes in female bearded and ringed seals during 1953-1968 (pre-1968, a period prior to sea ice decline) to 1998-2014 (post-1998, a period during sea ice decline). When comparing these periods, bearded seals had statistically higher cortisol concentrations post-1998, and for both species δ13C was more negative post-1998, while progesterone and δ15N did not change. There was a positive relationship between progesterone and cortisol Z-scores for both species, except for ringed seals post-1998. There was a negative relationship between cortisol Z-scores and δ13C for bearded seals evident in post-1998 indicating that higher cortisol Z-scores are associated with more negative δ13C in bearded seals in recent years. This negative relationship between cortisol and δ13C in bearded seals suggests a shift to higher prey diversity, possibly due to changes in sea ice in the Pacific Arctic evident post 1998. Progesterone Z-scores corresponded to expected differences among non-pregnant, unimplanted, implanted and post-partum individuals. Using these data, pregnancy history was determined for reproductive years for each individual female sampled, which could allow for yearly pregnancy rates to be calculated given a large enough representative sample of the population. These results combine decades of observational studies with hormones and stable isotopes to infer changes in reproduction, stress and diet, as well as the connection between these life history parameters.
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Affiliation(s)
| | - Shawna A Karpovich
- Alaska Department of Fish and Game, 1300 College Road, Fairbanks, AK 99701, USA
| | - Lori Quakenbush
- Alaska Department of Fish and Game, 1300 College Road, Fairbanks, AK 99701, USA
| | - Lori Polasek
- Alaska Department of Fish and Game, 1255 W 8 St, Juneau, AK 99802, USA
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29
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Lowe CL, Hunt KE, Robbins J, Seton RE, Rogers M, Gabriele CM, Neilson JL, Landry S, Teerlink SS, Buck CL. Patterns of cortisol and corticosterone concentrations in humpback whale ( Megaptera novaeangliae) baleen are associated with different causes of death. CONSERVATION PHYSIOLOGY 2021; 9:coab096. [PMID: 34987826 PMCID: PMC8710851 DOI: 10.1093/conphys/coab096] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 10/08/2021] [Accepted: 12/06/2021] [Indexed: 05/15/2023]
Abstract
Baleen whales are subject to a myriad of natural and anthropogenic stressors, but understanding how these stressors affect physiology is difficult. Measurement of adrenal glucocorticoid (GC) hormones involved in the vertebrate stress response (cortisol and corticosterone) in baleen could help fill this data gap. Baleen analysis is a powerful tool, allowing for a retrospective re-creation of multiple years of GC hormone concentrations at approximately a monthly resolution. We hypothesized that whales that died from acute causes (e.g. ship strike) would have lower levels of baleen GCs than whales that died from extended illness or injury (e.g. long-term entanglement in fishing gear). To test this hypothesis, we extracted hormones from baleen plates of four humpback whales (Megaptera novaeangliae) with well-documented deaths including multiple and chronic entanglements (n = 1, female), ship strike (n = 2, male and female) and chronic illness with nutritional stress (n = 1, male). Over ~3 years of baleen growth and during multiple entanglements, the entangled whale had average corticosterone levels of 80-187% higher than the other three whales but cortisol levels were similar to two of the other three whales. The nutritionally stressed and chronically ill whale showed a slow increase in both cortisol and corticosterone spanning ~3 years, followed by a sharp decline in both hormones before death, possibly indicative of adrenal failure in this moribund individual. This whale's correlation between cortisol and corticosterone was significant but there were no correlations in the other three whales. Our results show that cortisol and corticosterone concentrations vary according to the type and duration of illness or injury. Single-point GC concentrations should be interpreted with caution as low values can occur in whales experiencing pronounced stress and individual baselines can be highly variable. Baleen analysis is a promising tissue type for retrospective analyses of physiological responses to various stressors affecting baleen whales.
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Affiliation(s)
- Carley L Lowe
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86001, USA
- Corresponding author: Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86001, USA. Tel: 702-524-3667. Fax: 928-523-7500.
| | - Kathleen E Hunt
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86001, USA
- Smithsonian-Mason School of Conservation & George Mason University, Front Royal, VA 22630, USA
| | - Jooke Robbins
- Center for Coastal Studies, Provincetown, MA 02657, USA
| | - Rosemary E Seton
- Allied Whale, College of the Atlantic, Bar Harbor, ME 04609, USA
| | - Matthew Rogers
- NOAA Fisheries, Alaska Fisheries Science Center Auke Bay Laboratories, Juneau, AK 99801, USA
| | | | - Janet L Neilson
- Glacier Bay National Park & Preserve, Gustavus, AK 99826, USA
| | - Scott Landry
- Center for Coastal Studies, Provincetown, MA 02657, USA
| | - Suzie S Teerlink
- NOAA Fisheries, Alaska Regional Office, Protected Resources Division, Juneau AK, 99801 USA
| | - C Loren Buck
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86001, USA
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30
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Hudson JM, Matthews CJD, Watt CA. Detection of steroid and thyroid hormones in mammalian teeth. CONSERVATION PHYSIOLOGY 2021; 9:coab087. [PMID: 36439380 PMCID: PMC8633673 DOI: 10.1093/conphys/coab087] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 08/30/2021] [Accepted: 10/27/2021] [Indexed: 05/21/2023]
Abstract
Endocrine tools can provide an avenue to better understand mammalian life histories and predict how individuals and populations may respond to environmental stressors; however, few options exist for studying long-term endocrine patterns in individual marine mammals. Here, we (i) determined whether hormones could be measured in teeth from four marine mammal species: narwhal (Monodon monoceros), beluga (Delphinapterus leucas), killer whale (Orcinus orca) and Atlantic walrus (Odobenus rosmarus rosmarus); (ii) validated commercially available enzyme immunoassay kits for use with tooth extracts; and (iii) conducted biological validations for each species to determine whether reproductive hormone concentrations in teeth correlated with age of sexual maturity. Tooth extracts from all species had measurable concentrations of progesterone, testosterone, 17β-estradiol, corticosterone, aldosterone and triiodothyronine (T3); however, cortisol was undetectable. Parallelism between the binding curves of assay kit standards and serially diluted pools of tooth extract for each species was observed for all measurable hormones. Slopes of accuracy tests ranged from 0.750 to 1.116, with r2 values ranging from 0.977 to 1.000, indicating acceptable accuracy. Biological validations were inconsistent with predictions for each species, with the exception of female killer whales (n = 2), which assumed higher progesterone and testosterone concentrations in mature individuals than immature individuals. Instead, we observed a decline in progesterone and testosterone concentrations from infancy through adulthood in narwhal (n = 1) and walruses (n = 2) and higher reproductive hormone concentrations in immature individuals than mature individuals in belugas (n = 8 and 10, respectively) and male killer whales (n = 1 and 2, respectively). While unexpected, this pattern has been observed in other taxa; however, further analytical and biological validations are necessary before this technique can be used to assess individual mammalian endocrine patterns.
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Affiliation(s)
- Justine M Hudson
- Corresponding author: Fisheries and Oceans Canada, Winnipeg, R3T 2N6, Canada. Tel: 1 (204) 984-0550.
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31
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Fernández Ajó AA, Hunt KE, Giese AC, Sironi M, Uhart M, Rowntree VJ, Marón CF, Dillon D, DiMartino M, Buck CL. Retrospective analysis of the lifetime endocrine response of southern right whale calves to gull wounding and harassment: A baleen hormone approach. Gen Comp Endocrinol 2020; 296:113536. [PMID: 32540491 DOI: 10.1016/j.ygcen.2020.113536] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Revised: 05/28/2020] [Accepted: 06/08/2020] [Indexed: 11/30/2022]
Abstract
Physiological measurements are informative in assessing the relative importance of stressors that potentially impact the health of wildlife. Kelp Gulls, Larus dominicanus (KG), resident to the region of Península Valdés, Argentina, have developed a unique behavior of landing on the backs of southern right whale adults and calves, Eubalaena australis (SRW), where they feed on their skin and blubber. This parasitic behavior results in large open wounds on the dorsal surface of the whale. Coincidently, the SRW population off the coast of Península Valdés has experienced elevated calf mortality. We quantified levels of glucocorticoids and thyroid hormone extracted from baleen of dead calves to evaluate, retrospectively, the endocrine response of whale calves to gull wounding and harassment. Baleen accumulates hormones as it grows, allowing evaluation of long-term trends in physiological condition. While glucocorticoids (GCs) are known to increase in response to stressors such as disturbance, the metabolic hormone triiodothyronine (T3) has been shown to decrease under sustained food deprivation but is largely unaffected by disturbance stress. We quantified lifetime patterns of GCs and T3 in baleen recovered at necropsy from 36 southern right whale calves with varying severity of wounding from KGs. GC levels in baleen correlated positively with the degree of wounding, while T3 levels remained stable irrespective of the severity of the wounding. Our results suggest no evidence of malnutrition in low vs. severely wounded whales. However, the positive correlation of GCs with wound severity indicates that heavily wounded calves are suffering high levels of physiological stress before they die. This suggests that KG wounding may have contributed to the high southern right whale calf mortality observed in the Península Valdés region of Argentina.
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Affiliation(s)
- Alejandro A Fernández Ajó
- Department of Biological Sciences, Northern Arizona University, 617 S. Beaver St., PO Box 5640, Flagstaff, AZ 86011, USA; Instituto de Conservación de Ballenas, Capital Federal, O'Higgins 4380, Ciudad Autónoma de Buenos Aires 1429, Argentina.
| | - Kathleen E Hunt
- George Mason University, Smithsonian-Mason School of Conservation 1500 Remount Rd, Front Royal, VA 22630, USA
| | - A Carolina Giese
- Instituto Patagónico Para el Estudio de los Ecosistemas Continentales. IPEEC-CONICET, Bvd. Brown 2915 (9120), Puerto Madryn, Argentina
| | - Mariano Sironi
- Instituto de Conservación de Ballenas, Capital Federal, O'Higgins 4380, Ciudad Autónoma de Buenos Aires 1429, Argentina; Southern Right Whale Health Monitoring Program, Los Alerces 3376, Puerto Madryn, Chubut 9120, Argentina; Facultad de Ciencias Exactas, Físicas y Naturales (FCEFyN), Universidad Nacional de Córdoba, Av. Vélez Sársfield 299, Córdoba 5000, Argentina
| | - Marcela Uhart
- Southern Right Whale Health Monitoring Program, Los Alerces 3376, Puerto Madryn, Chubut 9120, Argentina; Wildlife Health Center, School of Veterinary Medicine, University of California, 1089 Veterinary Medicine Drive, VM3B Ground Floor, Davis, CA 95616, USA
| | - Victoria J Rowntree
- Instituto de Conservación de Ballenas, Capital Federal, O'Higgins 4380, Ciudad Autónoma de Buenos Aires 1429, Argentina; Southern Right Whale Health Monitoring Program, Los Alerces 3376, Puerto Madryn, Chubut 9120, Argentina; Department of Biology, University of Utah, 257 South 1400 East University of Utah, Salt Lake City, UT 84112, USA; Ocean Alliance/Whale Conservation Institute, 32 Horton St, Gloucester, MA 01930, USA
| | - Carina F Marón
- Instituto de Conservación de Ballenas, Capital Federal, O'Higgins 4380, Ciudad Autónoma de Buenos Aires 1429, Argentina; Facultad de Ciencias Exactas, Físicas y Naturales (FCEFyN), Universidad Nacional de Córdoba, Av. Vélez Sársfield 299, Córdoba 5000, Argentina
| | - Danielle Dillon
- Department of Biological Sciences, Northern Arizona University, 617 S. Beaver St., PO Box 5640, Flagstaff, AZ 86011, USA
| | - Matias DiMartino
- Southern Right Whale Health Monitoring Program, Los Alerces 3376, Puerto Madryn, Chubut 9120, Argentina
| | - C Loren Buck
- Department of Biological Sciences, Northern Arizona University, 617 S. Beaver St., PO Box 5640, Flagstaff, AZ 86011, USA
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Cates KA, Atkinson S, Pack AA, Straley JM, Gabriele CM, Yin S. Corticosterone in central North Pacific male humpback whales (Megaptera novaeangliae): Pairing sighting histories with endocrine markers to assess stress. Gen Comp Endocrinol 2020; 296:113540. [PMID: 32585212 DOI: 10.1016/j.ygcen.2020.113540] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 06/08/2020] [Accepted: 06/13/2020] [Indexed: 10/24/2022]
Abstract
Developing a better understanding of the stress response is critical to ensuring the health and sustainability of marine mammal populations. However, accurately measuring and interpreting a stress response in free-ranging, large cetaceans is a nascent field. Here, an enzyme immunoassay for corticosterone was validated for use in biopsy samples from male humpback whales (Megaptera novaeangliae). Analyses were conducted on 247 male North Pacific humpback whale blubber samples, including 238 non-calves and 9 calves that were collected on the Hawaiian breeding and Southeast Alaskan feeding grounds from 2004 to 2006. Significant relationships were found when corticosterone concentrations were examined by year, age class and distribution between locations. When examined by year, corticosterone concentrations for male humpback whales were higher in Hawaii in 2004 than in 2005 and 2006 (p < 0.05). Corticosterone concentration also varied by age class with initially high concentrations at birth which subsequently tapered off and remained relatively low until sexual maturity was reached around age 8-10 years. Corticosterone concentrations appeared to peak in male humpback whales around 15-25 years of age. Blubber biopsies from Alaska and Hawaii had similar mean corticosterone concentrations, yet the variability in these samples was much greater for whales located in Hawaii. It is clear that much work remains to be done in order to accurately define or monitor a stress response in male humpback whales and that specific attention is required when looking at age, sex, and yearly trends. Our results suggest that a stress response may be most impacted by age and yearly oceanographic conditions and needs to be initially examined at the individual level.
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Affiliation(s)
- Kelly A Cates
- University of Alaska Fairbanks, College of Fisheries and Ocean Sciences, Fisheries Department, Juneau Center, 17101 Pt. Lena Loop Road, Juneau, Alaska 99801, USA.
| | - Shannon Atkinson
- University of Alaska Fairbanks, College of Fisheries and Ocean Sciences, Fisheries Department, Juneau Center, 17101 Pt. Lena Loop Road, Juneau, Alaska 99801, USA
| | - Adam A Pack
- Departments of Psychology and Biology, University of Hawai'i at Hilo, 200 West Kawili Street, Hilo, Hawai'i 96720, USA; The Dolphin Institute, P.O. Box 6279, Hilo, Hawai'i 96720, USA
| | - Janice M Straley
- University of Alaska Southeast Sitka Campus, 1332 Seward Ave., Sitka, Alaska 99835, USA
| | | | - Suzanne Yin
- Hawai'i Marine Mammal Consortium, P.O. Box 6107, Kamuela, Hawai'i 96743, USA
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Larsen Tempel JT, Atkinson S. Endocrine profiling of reproductive status and evidence of pseudopregnancy in the Pacific walrus (Odobenus rosmarus divergens). PLoS One 2020; 15:e0239218. [PMID: 32931507 PMCID: PMC7491731 DOI: 10.1371/journal.pone.0239218] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 09/01/2020] [Indexed: 01/05/2023] Open
Abstract
Endocrine profiling is an increasingly utilized tool for detecting pregnancies in wild populations of mammals. Given the difficulty in calculating reproductive rates of Pacific walruses (Odobenus rosmarus divergens) the use of endocrine techniques for determining pregnancy rates could be particularly useful for management of the population. The goals of this study were to 1) determine if progesterone and total estrogen concentrations in ovarian tissues of female walruses could be used to determine reproductive state and 2) determine if walruses undergo a functional postpartum estrus, as is seen in other pinnipeds. Ovaries were collected from female walruses (n = 13) hunted in subsistence hunts by Alaska Native communities. Females were categorized as postpartum, full-term pregnant, pregnant diapause or unbred. Total estrogen concentrations were greatest in unbred (n = 2) and pregnant (n = 2) females. Progesterone concentrations were also nominally larger in unbred (n = 2) than pregnant (n = 2) and postpartum (n = 9) animals. Small samples sizes precluded the use of statistical comparisons among groups. Corpora lutea tissue samples in this study did not reflect the presence of a postpartum estrus in the month of May as postpartum females yielded lower total estrogen concentrations than unbred or pregnant animals. Both unbred animals were in a state of pseudopregnancy, which has not been physiologically described for this species before. The progesterone profiles in late (59 ng/g) and early (140 ng/g) pregnancy were lower than expected and fell within the range of the postpartum females (36-210 ng/g), suggesting low production of the hormone by the corpus luteum during these phases of pregnancy. Profiling reproductive hormones in free-ranging walruses demonstrates that an endocrine approach may be a valuable tool for determining reproductive status of females, however increased sample sizes and time of year must be considered to accurately separate pregnant versus pseudopregnant individuals.
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Affiliation(s)
- Jenell T. Larsen Tempel
- Fisheries Department, College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Juneau Campus, Juneau, Alaska, United States of America
| | - Shannon Atkinson
- Fisheries Department, College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Juneau Campus, Juneau, Alaska, United States of America
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Crain DD, Thomas A, Mansouri F, Potter CW, Usenko S, Trumble SJ. Hormone comparison between right and left baleen whale earplugs. CONSERVATION PHYSIOLOGY 2020; 8:coaa055. [PMID: 32607240 PMCID: PMC7311829 DOI: 10.1093/conphys/coaa055] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2019] [Revised: 02/06/2020] [Accepted: 05/31/2020] [Indexed: 05/24/2023]
Abstract
Marine animals experience additional stressors as humans continue to industrialize the oceans and as the climate continues to rapidly change. To examine how the environment or humans impact animal stress, many researchers analyse hormones from biological matrices. Scientists have begun to examine hormones in continuously growing biological matrices, such as baleen whale earwax plugs, baleen and pinniped vibrissae. Few of these studies have determined if the hormones in these tissues across the body of the organism are interchangeable. Here, hormone values in the right and left earplugs from the same individual were compared for two reasons: (i) to determine whether right and left earplug hormone values can be used interchangeably and (ii) to assess methods of standardizing hormones in right and left earplugs to control for individuals' naturally varying hormone expressions. We analysed how absolute, baseline-corrected and Z-score normalized hormones performed in reaching these goals. Absolute hormones in the right and left earplugs displayed a positive relationship, while using Z-score normalization was necessary to standardize the variance in hormone expression. After Z-score normalization, it was possible to show that the 95% confidence intervals of the differences in corresponding lamina of the right and left earplugs include zero for both cortisol and progesterone. This indicates that the hormones in corresponding lamina of right and left earplugs are no different from zero. The results of this study reveal that both right and left earplugs from the same baleen whale can be used in hormone analyses after Z-score normalization. This study also shows the importance of Z-score normalization to interpretation of results and methodologies associated with analysing long-term trends using whale earplugs.
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Affiliation(s)
- Danielle D Crain
- Department of Biology, Baylor University, 101 Bagby Ave. Waco TX 76706, USA
| | - Amanda Thomas
- Department of Biology, Baylor University, 101 Bagby Ave. Waco TX 76706, USA
| | - Farzaneh Mansouri
- Department of Environmental Science, Baylor University, 101 Bagby Ave. Waco TX 76706, USA
| | - Charles W Potter
- Department of Vertebrate Zoology, Smithsonian Institution National Museum of Natural History, PO Box 37012 SI Bldg, Room 153, MRC 010, Washington, DC 20013 USA
| | - Sascha Usenko
- Department of Biology, Baylor University, 101 Bagby Ave. Waco TX 76706, USA
- Department of Environmental Science, Baylor University, 101 Bagby Ave. Waco TX 76706, USA
- Department of Chemistry and Biochemistry, Baylor University, 101 Bagby Ave. Waco TX 76706, USA
| | - Stephen J Trumble
- Department of Biology, Baylor University, 101 Bagby Ave. Waco TX 76706, USA
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Davidson I, Altory-Natour A, Haddas R, Nagar S, Meir R, Avital-Cohen N, Rozenboim I. Evaluation of Viral-Induced Stress by Quantitating Corticosterone in Feathers of Virus-Infected Specific Pathogen-Free Chicks. J APPL POULTRY RES 2020. [DOI: 10.3382/japr/pfz027] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
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Harris BN. Stress hypothesis overload: 131 hypotheses exploring the role of stress in tradeoffs, transitions, and health. Gen Comp Endocrinol 2020; 288:113355. [PMID: 31830473 DOI: 10.1016/j.ygcen.2019.113355] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 12/06/2019] [Accepted: 12/06/2019] [Indexed: 12/11/2022]
Abstract
Stress is ubiquitous and thus, not surprisingly, many hypotheses and models have been created to better study the role stress plays in life. Stress spans fields and is found in the literature of biology, psychology, psychophysiology, sociology, economics, and medicine, just to name a few. Stress, and the hypothalamic-pituitaryadrenal/interrenal (HPA/I) axis and sympathetic nervous system (SNS), are involved in a multitude of behaviors and physiological processes, including life-history and ecological tradeoffs, developmental transitions, health, and survival. The goal of this review is to highlight and summarize the large number of available hypotheses and models, to aid in comparative and interdisciplinary thinking, and to increase reproducibility by a) discouraging hypothesizing after results are known (HARKing) and b) encouraging a priori hypothesis testing. For this review I collected 214 published hypotheses or models dealing broadly with stress. In the main paper, I summarized and categorized 131 of those hypotheses and models which made direct connections among stress and/or HPA/I and SNS, tradeoffs, transitions, and health. Of those 131, the majority made predictions about reproduction (n = 43), the transition from health to disease (n = 38), development (n = 23), and stress coping (n = 18). Additional hypotheses were classified as stage-spanning or models (n = 37). The additional 83 hypotheses found during searches were tangentially related, or pertained to immune function or oxidative stress, and these are listed separately. Many of the hypotheses share underlying rationale and suggest similar, if not identical, predictions, and are thus not mutually exclusive; some hypotheses spanned classification categories. Some of the hypotheses have been tested multiple times, whereas others have only been examined a few times. It is the hope that multi-disciplinary stress researchers will begin to harmonize their naming of hypotheses in the literature so as to build a clearer picture of how stress impacts various outcomes across fields. The paper concludes with some considerations and recommendations for robust testing of stress hypotheses.
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Affiliation(s)
- Breanna N Harris
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, United States.
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Keogh MJ, Gastaldi A, Charapata P, Melin S, Fadely BS. Stress-related and reproductive hormones in hair from three north Pacific otariid species: Steller sea lions, California sea lions and northern fur seals. CONSERVATION PHYSIOLOGY 2020; 8:coaa069. [PMID: 32843968 PMCID: PMC7437363 DOI: 10.1093/conphys/coaa069] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 05/08/2020] [Accepted: 07/05/2020] [Indexed: 05/05/2023]
Abstract
Assessing the physiological impact of stressors in pinnipeds is logistically challenging, and many hormones are altered by capture and handling, limiting the utility of metabolically active tissues. Hair is increasingly being used to investigate stress-related and reproductive hormones in wildlife populations due to less-invasive collection methods, being metabolically inert once grown and containing multiple biomarkers of ecological interest. We validated enzyme immunoassays for measuring aldosterone, cortisol, corticosterone, and testosterone in lanugo (natal hair grown in utero) samples collected from Steller sea lions (Eumetopias jubatus), California sea lions (Zalophus californianus), and northern fur seals (Callorhinus ursinus). We applied laboratory validation methods including recovery of added mass, parallelism and dilution linearity. We found no effects due to differences in alcohol- versus detergent-based cleaning methods. Further, there were no significant differences in hormone concentrations in hair samples collected immediately after the molt and the subsequent samples collected over 1 year, indicating steroid hormones are stable once deposited into pinniped hair. We found no sex differences in any hormone concentrations, likely due to the lanugo being grown in utero and influenced by maternal hormone concentrations. For Steller sea lion and California sea lion pups, we found hormone concentrations significantly differed between rookeries, which warrants future research. Hair provides a novel tissue to explore the intrinsic or extrinsic drivers behind hormone measurements in otariids, which can be paired with multiple health-related metrics to further investigate possible drivers of physiological stress.
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Affiliation(s)
- Mandy J Keogh
- Division of Wildlife Conservation, Alaska Department of Fish and Game, P.O. Box 110024 Douglas, AK 99811-0024, USA
- Corresponding author:
| | - Angela Gastaldi
- Division of Wildlife Conservation, Alaska Department of Fish and Game, 1300 College Road, Fairbanks, AK 99701, USA
| | - Patrick Charapata
- Division of Wildlife Conservation, Alaska Department of Fish and Game, 1300 College Road, Fairbanks, AK 99701, USA
- Department of Biology, Baylor University, One Bear Place, Waco, TX 67679, USA
| | - Sharon Melin
- Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 7600 Sand Point Way NE, Seattle, WA 98115
| | - Brian S Fadely
- Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 7600 Sand Point Way NE, Seattle, WA 98115
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Karpovich SA, Horstmann LA, Polasek LK. Validation of a novel method to create temporal records of hormone concentrations from the claws of ringed and bearded seals. CONSERVATION PHYSIOLOGY 2020; 8:coaa073. [PMID: 32864135 PMCID: PMC7446537 DOI: 10.1093/conphys/coaa073] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 05/29/2020] [Accepted: 08/03/2020] [Indexed: 05/12/2023]
Abstract
Ringed (Pusa hispida) and bearded seals (Erignathus barbatus) inhabit vast and often remote areas in the Arctic, making it difficult to obtain long-term physiological information concerning health and reproduction. These seals are experiencing climate-driven changes in their habitat that could result in physiological stress. Chronic physiological stress can lead to immunosuppression, decreased reproduction and decreased growth. Recently, keratin has become a popular matrix to measure steroid hormones, such as stress-related cortisol and reproduction-related progesterone. We developed and validated methods to extract cortisol and progesterone from the claws of adult female ringed (n = 20) and bearded (n = 3) seals using enzyme immunosorbent assays. As ringed and bearded seal claws grow, a pair of dark- and light-colored bands of keratin is deposited annually providing a guide for sampling. Two processing methods were evaluated, removal of claw material with a grinding bit or grinding followed by mechanical pulverization (102 paired samples from six claws, two each from three seals). Adding the mechanical pulverization step resulted in a 1.5-fold increase in hormone extraction. Progesterone from the proximal claw band was evaluated to biologically validate claw material as a measure of pregnancy in ringed seals (n = 14). Claws from pregnant seals had significantly higher claw progesterone concentrations than from non-pregnant seals. This suggests that the elevated progesterone associated with gestation was reflected in the claws, and that the most proximal claw band was indicative of pregnancy status at time of death. Thus, although the sample size was low and the collection dates unbalanced, this study demonstrates the potential to use claws to examine an extended time series (up to 12 yrs) of cortisol and progesterone concentrations in ringed and bearded seal claws.
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Affiliation(s)
- Shawna A Karpovich
- Alaska Department of Fish and Game, Marine Mammal Program, Fairbanks, AK 99701, USA
- Corresponding author: Alaska Department of Fish and Game, Marine Mammal Program, Fairbanks, AK 99701, USA. Tel: 907 459 7322.
| | - Larissa A Horstmann
- College of Fisheries and Ocean Sciences, University of Alaska, Fairbanks, AK 99775, USA
| | - Lori K Polasek
- Alaska Department of Fish and Game, Marine Mammal Program, Juneau, AK 99811, USA
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39
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Galligan TM, Boggs ASP, Balmer BC, Rowles T, Smith CR, Townsend F, Wells RS, Kellar NM, Zolman ES, Schwacke LH. Blubber steroid hormone profiles as indicators of physiological state in free-ranging common bottlenose dolphins (Tursiops truncatus). Comp Biochem Physiol A Mol Integr Physiol 2019; 239:110583. [PMID: 31648064 DOI: 10.1016/j.cbpa.2019.110583] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 09/27/2019] [Accepted: 10/01/2019] [Indexed: 02/08/2023]
Abstract
Blubber has been proposed as a possible alternative to blood in the assessment of endocrine physiology in marine mammals because it can be collected via remote biopsy, which removes some of the confounding variables and logistical constraints associated with blood collection. To date, few studies have directly assessed the relationships between circulating versus blubber steroid hormone profiles in marine mammals, and these studies have been limited to a small subset of steroid hormones, which collectively limit the current utility of blubber steroid hormone measurements. In this study, we used liquid-chromatography tandem-mass spectrometry (LC-MS/MS) to screen for 16 steroid hormones in matched blood and blubber samples from free-ranging common bottlenose dolphins (Tursiops truncatus). Seven steroid hormones were detected and quantified, including two progestogens, two androgens, and three corticosteroids. Using principal components analysis (PCA), we explored relationships between hormones in both matrices and three physiological states: sexual maturity, pregnancy, and acute stress response. Plasma and blubber testosterone and its precursors, 17-hydroxyprogesterone and androstenedione, loaded to the first principal component (PC1), and PC1 scores were higher in mature males. Plasma and blubber progesterone loaded to PC2, and pregnant/probable pregnant females had significantly higher PC2 scores. Pregnant females also had higher PC1 scores than other females, suggesting differences in androgen profiles between these groups. There was disagreement between plasma and blubber corticosteroid profiles, as indicated by their loading to different PCs; plasma corticosteroids loaded to PC3 and blubber corticosteroids to PC4. PC3 scores were significantly predicted by elapsed time to blood collection (i.e., time between initiating the capture process and blood collection), while elapsed time to blubber collection significantly predicted PC4 scores, indicating that corticosteroid profiles shift in both tissues during acute stress. Corticosteroid profiles were not related to demographic group, site-month, body mass index, water temperature, or time spent outside of the water on the processing boat. Overall, these results demonstrate that blubber steroid hormone profiles reflect changes in endocrine function that occur over broad temporal scales.
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Affiliation(s)
- Thomas M Galligan
- Hollings Marine Laboratory, Medical University of South Carolina, 331 Fort Johnson Rd, Charleston, SC 29412, USA; Department of Fish and Wildlife Conservation, College of Natural Resources and the Environment, Virginia Tech, 101 Cheatham Hall, 310 West Campus Dr., Blacksburg, VA 24060, USA.
| | - Ashley S P Boggs
- National Institute of Standards and Technology, Chemical Sciences Division, Hollings Marine Laboratory, 331 Fort Johnson Road, Charleston, SC 29412, USA
| | - Brian C Balmer
- National Marine Mammal Foundation, 2240 Shelter Island Drive, Suite 200, San Diego, CA 92106, USA
| | - Teri Rowles
- Office of Protected Resources, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 1315 East-West Highway, Silver Spring, MD 20910, USA
| | - Cynthia R Smith
- National Marine Mammal Foundation, 2240 Shelter Island Drive, Suite 200, San Diego, CA 92106, USA
| | - Forrest Townsend
- Bayside Hospital for Animals, 251 Racetrack Road NE, Fort Walton Beach, FL 32547, USA
| | - Randall S Wells
- Chicago Zoological Society's Sarasota Dolphin Research Program, c/o Mote Marine Laboratory, 1600 Ken Thompson Pkwy, Sarasota, FL 34236, USA
| | - Nicholas M Kellar
- Ocean Associates, Inc., under contract to the Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 4007 N Abingdon St, Arlington, VA 22207, USA
| | - Eric S Zolman
- National Marine Mammal Foundation, 2240 Shelter Island Drive, Suite 200, San Diego, CA 92106, USA
| | - Lori H Schwacke
- National Marine Mammal Foundation, 2240 Shelter Island Drive, Suite 200, San Diego, CA 92106, USA
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40
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Laberge F, Yin-Liao I, Bernier NJ. Temporal profiles of cortisol accumulation and clearance support scale cortisol content as an indicator of chronic stress in fish. CONSERVATION PHYSIOLOGY 2019; 7:coz052. [PMID: 31620290 PMCID: PMC6788491 DOI: 10.1093/conphys/coz052] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Revised: 06/15/2019] [Accepted: 07/05/2019] [Indexed: 05/31/2023]
Abstract
The development of chronic stress indicators for fish is of great interest, but appropriate non-invasive methods are lagging those used in terrestrial vertebrates. Here, we explore the possibility that levels of the stress hormone cortisol in scales could be used as a chronic stress indicator. Three experiments were conducted to assess the temporal profiles of cortisol rise and fall in plasma and scales of goldfish (Carassius auratus) in response to stressors of varying intensity and duration. Results show that a single acute air emersion stressor does not influence scale cortisol content. In contrast, relative to plasma levels, the fall in scale cortisol content following a high-dose cortisol implant is delayed by at least 8 days, and the rise and fall in scale cortisol content in response to unpredictable chronic stress are delayed by at least 7 days. Also, scale cortisol content is spatially heterogeneous across the body surface of goldfish. Overall, since high and sustained circulating cortisol levels are needed to influence scale cortisol content and the rates of cortisol accumulation and clearance are much slower in scales than in plasma, our results show that scales can provide an integrated measure of cortisol production and serve as a chronic stress indicator.
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Affiliation(s)
- Frédéric Laberge
- Department of Integrative Biology, University of Guelph, 50 Stone Road East, Guelph, ON, Canada, N1G 2WI
| | - Irene Yin-Liao
- Department of Integrative Biology, University of Guelph, 50 Stone Road East, Guelph, ON, Canada, N1G 2WI
| | - Nicholas J Bernier
- Department of Integrative Biology, University of Guelph, 50 Stone Road East, Guelph, ON, Canada, N1G 2WI
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Kalliokoski O, Jellestad FK, Murison R. A systematic review of studies utilizing hair glucocorticoids as a measure of stress suggests the marker is more appropriate for quantifying short-term stressors. Sci Rep 2019; 9:11997. [PMID: 31427664 PMCID: PMC6701156 DOI: 10.1038/s41598-019-48517-2] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Accepted: 08/07/2019] [Indexed: 12/11/2022] Open
Abstract
Quantitating glucocorticoids (GCs) in hairs is a popular method for assessing chronic stress in studies of humans and animals alike. The cause-and-effect relationship between stress and elevated GC levels in hairs, sampled weeks later, is however hard to prove. This systematic review evaluated the evidence supporting hair glucocorticoids (hGCs) as a biomarker of stress. Only a relatively small number of controlled studies employing hGC analyses have been published, and the quality of the evidence is compromised by unchecked sources of bias. Subjects exposed to stress mostly demonstrate elevated levels of hGCs, and these concentrations correlate significantly with GC concentrations in serum, saliva and feces. This supports hGCs as a biomarker of stress, but the dataset provided no evidence that hGCs are a marker of stress outside of the immediate past. Only in cases where the stressor persisted at the time of hair sampling could a clear link between stress and hGCs be established.
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Affiliation(s)
- Otto Kalliokoski
- Department of Experimental Medicine, University of Copenhagen, Copenhagen, Denmark.
| | - Finn K Jellestad
- Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway
| | - Robert Murison
- Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway
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Rosenbaum S, Gettler LT. With a little help from her friends (and family) part II: Non-maternal caregiving behavior and physiology in mammals. Physiol Behav 2019; 193:12-24. [PMID: 29933837 DOI: 10.1016/j.physbeh.2017.12.027] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 12/21/2017] [Indexed: 12/15/2022]
Abstract
The diversity of competing frameworks for explaining the evolution of non-maternal care in mammals (Part I, this issue) reflects the vast range of behaviors and associated outcomes these theories attempt to subsume. Caretaking comprises a wide variety of behavioral domains, and is mediated by an equally large range of physiological systems. In Part II, we provide an overview of how non-maternal care in mammals is expressed, the ways in which it is regulated, and the many effects such care has on both recipients and caretakers. We also discuss the two primary ways in which closer integration of ultimate and proximate levels of explanation can be useful when addressing questions about non-maternal caretaking. Specifically, proximate mechanisms provide important functional clues, and are key to testing theory concerning evolutionary tradeoffs. Finally, we highlight a number of methodological and publication biases that currently shape the literature, which provide opportunities for knowledge advancement in this domain going forward. In this conclusion to our two-part introduction, we provide a broad survey of the behavior and physiology that the contributions to this special issue represent.
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Affiliation(s)
- Stacy Rosenbaum
- Department of Anthropology, Northwestern University, Evanston, IL, United States; Davee Center for Epidemiology and Endocrinology, Lincoln Park Zoo, Chicago, IL, United States.
| | - Lee T Gettler
- Department of Anthropology, University of Notre Dame, Notre Dame, IN, United States; The Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, United States
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Charapata P, Horstmann L, Jannasch A, Misarti N. A novel method to measure steroid hormone concentrations in walrus bone from archaeological, historical, and modern time periods using liquid chromatography/tandem mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2018; 32:1999-2023. [PMID: 30192037 PMCID: PMC6282614 DOI: 10.1002/rcm.8272] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 08/15/2018] [Accepted: 08/19/2018] [Indexed: 05/24/2023]
Abstract
RATIONALE A liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was validated and utilized to measure and analyze four steroid hormones related to stress and reproduction in individual samples from a novel tissue, Pacific walrus (Odobenus rosmarus divergens, herein walrus) bone. This method determines steroid hormone concentrations in the remote walrus population over millennia from archaeological (>200 bp), historical (200-20 bp), and modern (2014-2016) time periods. METHODS Lipids were extracted from walrus bone collected from these periods using methanol before LC/MS/MS analysis. Isotopically labeled internal standards for each target hormone were added to every sample. Analytical and physiological validations were performed. Additionally, a tissue comparison was done among paired walrus bone, serum, and blubber samples. A rapid resolution liquid chromatography system coupled to a QqQ mass spectrometer was used to analyze all samples after derivatization for progesterone, testosterone, cortisol, and estradiol concentrations. Multiple reaction monitoring was used for MS analysis and data were acquired in positive electrospray ionization mode. RESULTS Progesterone, testosterone, cortisol, and estradiol were linear along their respective standard calibration curves based on their R2 values (all > 0.99). Accuracy ranged from 93-111% for all hormones. The recovery of extraction, recovery of hormones without matrix effect, was 92-101%. The overall process efficiency of our method for measuring hormones in walrus bone was 93-112%. Progesterone and testosterone concentrations were not affected by reproductive status among adult females and males, respectively. However, estradiol was different among pregnant and non-pregnant adult females. Overall, steroid hormones reflect a long-term reservoir in cortical bone. This method was also successfully applied to walrus bone as old as 3585 bp. CONCLUSIONS LC/MS/MS analysis of bone tissue (0.2-0.3 g) provides stress and reproductive data from elusive walruses that were alive thousands of years ago. Based on physiological validations, tissue comparison, and published literature, steroid hormone concentrations measured in walrus cortical bone could represent an accumulated average around a 10-20-year time span. By investigating how stress and reproductive physiology may have changed over the past ~3000 years based on bone steroid hormone concentrations, this method will help answer how physiologically resilient walruses are to climate change in the Arctic.
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Affiliation(s)
- Patrick Charapata
- College of Fisheries and Ocean SciencesUniversity of Alaska FairbanksPO Box 757220FairbanksAK99775USA
- Department of BiologyBaylor UniversityOne Bear PlaceWacoTX76706USA
| | - Lara Horstmann
- College of Fisheries and Ocean SciencesUniversity of Alaska FairbanksPO Box 757220FairbanksAK99775USA
| | - Amber Jannasch
- Bindley Bioscience CenterPurdue University1203 W State St.West LafayetteIN47906USA
| | - Nicole Misarti
- Water and Environmental Research CenterUniversity of Alaska FairbanksPO Box 755910FairbanksAK99775USA
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Baleen whale cortisol levels reveal a physiological response to 20th century whaling. Nat Commun 2018; 9:4587. [PMID: 30389921 PMCID: PMC6215000 DOI: 10.1038/s41467-018-07044-w] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 10/09/2018] [Indexed: 01/15/2023] Open
Abstract
One of the most important challenges researchers and managers confront in conservation ecology is predicting a population's response to sub-lethal stressors. Such predictions have been particularly elusive when assessing responses of large marine mammals to past anthropogenic pressures. Recently developed techniques involving baleen whale earplugs combine age estimates with cortisol measurements to assess spatial and temporal stress/stressor relationships. Here we show a relationship between baseline-corrected cortisol levels and corresponding whaling counts of fin, humpback, and blue whales in the Northern Hemisphere spanning the 20th century. We also model the impact of alternative demographic and environmental factors and determine that increased anomalies of sea surface temperature over a 46-year mean (1970-2016) were positively associated with cortisol levels. While industrial whaling can deplete populations by direct harvest, our data underscore a widespread stress response in baleen whales that is peripheral to whaling activities or associated with other anthropogenic change.
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Hamilton MT, Finger JW, Elsey RM, Mastromonaco GF, Tuberville TD. Corticosterone in American alligator (Alligator mississippiensis) tail scutes: Evaluating the feasibility of using unconventional samples for investigating environmental stressors. Gen Comp Endocrinol 2018; 268:7-13. [PMID: 30031024 DOI: 10.1016/j.ygcen.2018.07.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 06/23/2018] [Accepted: 07/13/2018] [Indexed: 12/31/2022]
Abstract
Baseline plasma corticosterone (CORT) concentrations have been widely used to investigate the effects of stressors in wild and captive crocodilians. However, collecting baseline plasma CORT samples from wild crocodilians may be particularly difficult due to the capture and handling protocols used for large individuals. Thus, it may prove beneficial to use recently modified techniques for extracting CORT deposited in keratinized and non-keratinized tissues to better quantify the effects of long-term stress in crocodilians. In this study, we investigated the feasibility of using American alligator (Alligator mississippiensis) tail scute tissues to quantify CORT by collecting blood and tail scutes from 40 alligators before and after a short-term handling stressor. The objective of the current study was to better understand CORT deposition in crocodilian scutes and whether short-term increases in CORT could be detected. We found that CORT can be reliably extracted from alligator scute tissue and quantified using a commercially available enzyme immunoassay. However, there was a significant increase in scute CORT concentrations following an alligator being exposed to a short-term stressor (p = 0.017), although the magnitude of change was less than observed in plasma samples from the same individuals (p = 0.002). Furthermore, our results indicate that there was a significant effect of body condition on an alligator's post-stressor CORT concentration (p = 0.02). While our study is among the first to experimentally examine the usefulness of tissue CORT in crocodilians, a combination of field and laboratory experiments are needed to better understand deposition rates of CORT in scute tissues and to further validate the usefulness of tissue glucocorticoids for evaluating the effects of stress.
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Affiliation(s)
- Matthew T Hamilton
- Savannah River Ecology Laboratory, University of Georgia, Aiken, SC 29802, USA.
| | - John W Finger
- Savannah River Ecology Laboratory, University of Georgia, Aiken, SC 29802, USA; Department of Environmental Health Science, University of Georgia, Athens, GA 30602, USA
| | - Ruth M Elsey
- Louisiana Department of Wildlife and Fisheries, Rockefeller Wildlife Refuge, Grand Chenier, LA 70643, USA
| | | | - Tracey D Tuberville
- Savannah River Ecology Laboratory, University of Georgia, Aiken, SC 29802, USA
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Hunt KE, Lysiak NSJ, Matthews CJD, Lowe C, Fernández Ajó A, Dillon D, Willing C, Heide-Jørgensen MP, Ferguson SH, Moore MJ, Buck CL. Multi-year patterns in testosterone, cortisol and corticosterone in baleen from adult males of three whale species. CONSERVATION PHYSIOLOGY 2018; 6:coy049. [PMID: 30254748 PMCID: PMC6148970 DOI: 10.1093/conphys/coy049] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 08/05/2018] [Accepted: 09/01/2018] [Indexed: 05/03/2023]
Abstract
Male baleen whales have long been suspected to have annual cycles in testosterone, but due to difficulty in collecting endocrine samples, little direct evidence exists to confirm this hypothesis. Potential influences of stress or adrenal stress hormones (cortisol, corticosterone) on male reproduction have also been difficult to study. Baleen has recently been shown to accumulate steroid hormones during growth, such that a single baleen plate contains a continuous, multi-year retrospective record of the whale's endocrine history. As a preliminary investigation into potential testosterone cyclicity in male whales and influences of stress, we determined patterns in immunoreactive testosterone, two glucocorticoids (cortisol and corticosterone), and stable-isotope (SI) ratios, across the full length of baleen plates from a bowhead whale (Balaena mysticetus), a North Atlantic right whale (Eubalaena glacialis) and a blue whale (Balaenoptera musculus), all adult males. Baleen was subsampled at 2 cm (bowhead, right) or 1 cm (blue) intervals and hormones were extracted from baleen powder with methanol, followed by quantification of all three hormones using enzyme immunoassays validated for baleen extract of these species. Baleen of all three males contained regularly spaced peaks in testosterone content, with number and spacing of testosterone peaks corresponding well to SI data and to species-specific estimates of annual baleen growth rate. Cortisol and corticosterone exhibited some peaks that co-occurred with testosterone peaks, while other glucocorticoid peaks occurred independent of testosterone peaks. The right whale had unusually high glucocorticoids during a period with a known entanglement in fishing gear and a possible disease episode; in the subsequent year, testosterone was unusually low. Further study of baleen testosterone patterns in male whales could help clarify conservation- and management-related questions such as age of sexual maturity, location and season of breeding, and the potential effect of anthropogenic and natural stressors on male testosterone cycles.
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Affiliation(s)
- Kathleen E Hunt
- Department of Biological Sciences, Center for Bioengineering Innovation, Northern Arizona University, Flagstaff, AZ, USA
| | - Nadine S J Lysiak
- Biology Department, University of Massachusetts Boston, Boston, MA, USA
| | - Cory J D Matthews
- Arctic Aquatic Research Division, Fisheries and Oceans Canada, Winnipeg, MB, Canada
| | - Carley Lowe
- Department of Biological Sciences, Center for Bioengineering Innovation, Northern Arizona University, Flagstaff, AZ, USA
| | - Alejandro Fernández Ajó
- Department of Biological Sciences, Center for Bioengineering Innovation, Northern Arizona University, Flagstaff, AZ, USA
| | - Danielle Dillon
- Department of Biological Sciences, Center for Bioengineering Innovation, Northern Arizona University, Flagstaff, AZ, USA
| | - Cornelia Willing
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, Canada
| | | | - Steven H Ferguson
- Arctic Aquatic Research Division, Fisheries and Oceans Canada, Winnipeg, MB, Canada
| | - Michael J Moore
- Marine Mammal Center, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - C Loren Buck
- Department of Biological Sciences, Center for Bioengineering Innovation, Northern Arizona University, Flagstaff, AZ, USA
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Dunlop RA, Noad MJ, McCauley RD, Kniest E, Slade R, Paton D, Cato DH. A behavioural dose-response model for migrating humpback whales and seismic air gun noise. MARINE POLLUTION BULLETIN 2018; 133:506-516. [PMID: 30041344 DOI: 10.1016/j.marpolbul.2018.06.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 03/29/2018] [Accepted: 06/03/2018] [Indexed: 06/08/2023]
Abstract
The behavioural responses of migrating humpback whales to an air gun, a small clustered seismic array and a commercial array were used to develop a dose-response model, accounting for the presence of the vessel, array towpath relative to the migration and social and environmental parameters. Whale groups were more likely to show an avoidance response (increasing their distance from the source) when the received sound exposure level was over 130 dB re 1 μPa2·s and they were within 4 km of the source. The 50% probability of response occurred where received levels were 150-155 dB re 1 μPa2·s and they were within 2.5 km of the source. A small number of whales moving rapidly close to the source vessel did not exhibit an avoidance response at the highest received levels (160-170 dB re 1 μPa2·s) meaning it was not possible to estimate the maximum response threshold.
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Affiliation(s)
- Rebecca A Dunlop
- Cetacean Ecology and Acoustics Laboratory, School of Veterinary Science, The University of Queensland, Gatton, Queensland 4343, Australia.
| | - Michael J Noad
- Cetacean Ecology and Acoustics Laboratory, School of Veterinary Science, The University of Queensland, Gatton, Queensland 4343, Australia
| | | | - Eric Kniest
- School of Engineering, University of Newcastle, Callaghan, NSW, 2308, Australia
| | - Robert Slade
- Blue Planet Marine, P.O. Box 919, Canberra ACT 2614, Australia
| | - David Paton
- Blue Planet Marine, P.O. Box 919, Canberra ACT 2614, Australia
| | - Douglas H Cato
- School of Geosciences, University of Sydney and Defence Science and Technology Group, Sydney, NSW 2006, Australia
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Madliger CL, Love OP, Hultine KR, Cooke SJ. The conservation physiology toolbox: status and opportunities. CONSERVATION PHYSIOLOGY 2018; 6:coy029. [PMID: 29942517 PMCID: PMC6007632 DOI: 10.1093/conphys/coy029] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 05/18/2018] [Accepted: 05/24/2018] [Indexed: 05/21/2023]
Abstract
For over a century, physiological tools and techniques have been allowing researchers to characterize how organisms respond to changes in their natural environment and how they interact with human activities or infrastructure. Over time, many of these techniques have become part of the conservation physiology toolbox, which is used to monitor, predict, conserve, and restore plant and animal populations under threat. Here, we provide a summary of the tools that currently comprise the conservation physiology toolbox. By assessing patterns in articles that have been published in 'Conservation Physiology' over the past 5 years that focus on introducing, refining and validating tools, we provide an overview of where researchers are placing emphasis in terms of taxa and physiological sub-disciplines. Although there is certainly diversity across the toolbox, metrics of stress physiology (particularly glucocorticoids) and studies focusing on mammals have garnered the greatest attention, with both comprising the majority of publications (>45%). We also summarize the types of validations that are actively being completed, including those related to logistics (sample collection, storage and processing), interpretation of variation in physiological traits and relevance for conservation science. Finally, we provide recommendations for future tool refinement, with suggestions for: (i) improving our understanding of the applicability of glucocorticoid physiology; (ii) linking multiple physiological and non-physiological tools; (iii) establishing a framework for plant conservation physiology; (iv) assessing links between environmental disturbance, physiology and fitness; (v) appreciating opportunities for validations in under-represented taxa; and (vi) emphasizing tool validation as a core component of research programmes. Overall, we are confident that conservation physiology will continue to increase its applicability to more taxa, develop more non-invasive techniques, delineate where limitations exist, and identify the contexts necessary for interpretation in captivity and the wild.
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Affiliation(s)
- Christine L Madliger
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental Science, Carleton University, 1125 Colonel By Dr., Ottawa, Ontario, Canada
- Department of Biological Sciences, University of Windsor, 401 Sunset Ave., Ontario, Canada
| | - Oliver P Love
- Department of Biological Sciences, University of Windsor, 401 Sunset Ave., Ontario, Canada
| | - Kevin R Hultine
- Department of Research, Conservation and Collections, Desert Botanical Garden, 1201 N. Galvin Parkway, Phoenix, AZ, USA
| | - Steven J Cooke
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental Science, Carleton University, 1125 Colonel By Dr., Ottawa, Ontario, Canada
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Pomerleau C, Matthews CJD, Gobeil C, Stern GA, Ferguson SH, Macdonald RW. Mercury and stable isotope cycles in baleen plates are consistent with year-round feeding in two bowhead whale (Balaena mysticetus) populations. Polar Biol 2018. [DOI: 10.1007/s00300-018-2329-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Abstract
This chapter presents the pathology of cetaceans, a diverse group of mammals restricted exclusively to aquatic habitats. The taxa include the largest mammals on earth, the baleen whales, as well as marine and freshwater toothed whales, dolphins, and porpoises. Pathologies of these species include infectious, toxic, and other disease processes, such as ship strike and entanglements in free-ranging animals. In animals under managed care, concerns include nutritional, degenerative and geriatric processes, such as formation of ammonium urate renal calculi. Due to potential population level effects and individual animal health concerns, viral agents of interest include morbilliviruses, pox virus, and herpes viruses. Both free ranging and captive animals have important neoplasms, including a variety of toxin-related tumors in beluga whales from the St. Lawrence Estuary and oral squamous cell carcinomas in bottlenose dolphins in managed care.
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