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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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2
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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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3
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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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4
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Branco JM, Hingst-Zaher E, Dillon D, Jordan-Ward R, Siegrist J, Fischer JD, Schiesari L, von Hippel FA, Buck CL. A novel method for extraction and quantification of feather triiodothyronine (T3) and application to ecotoxicology of Purple Martin (Progne subis). ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 332:121943. [PMID: 37301461 DOI: 10.1016/j.envpol.2023.121943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 05/29/2023] [Accepted: 05/30/2023] [Indexed: 06/12/2023]
Abstract
Seventy-three percent of aerial insectivore species of birds breeding in North America have declined in the past five years. This decline is even greater in migratory insectivorous species, which face stressors in both their breeding and non-breeding ranges. The Purple Martin (Progne subis) is an aerial insectivore swallow that overwinters in South America and migrates to North America to breed. Purple Martin populations have declined by an estimated 25% since 1966. The eastern subspecies (P. subis subis) has declined the most and overwinters in the Amazon Basin, a region rich in environmental mercury (Hg) contamination. Previous studies reported elevated levels of Hg in feathers of this subspecies, which correlated negatively with body mass and fat reserves. Given the propensity of Hg to disrupt the endocrine system, and the role of thyroid hormones in regulating fat metabolism, this study quantifies concentrations of Hg and the thyroid hormone triiodothyronine (T3) in the feathers of P. subis subis. To our knowledge, this is the first study to extract and quantify T3 in feathers; thus, we developed, tested, and optimized a method for extracting T3 from feather tissue and validated an enzyme immunoassay (EIA) to quantify T3 in Purple Martin feathers. The developed method yielded acceptable results for both parallelism and accuracy. The observed T3 concentrations were statistically modeled along with total Hg (THg) concentrations, but these variables were not significantly correlated. This suggests that the observed variation in THg concentration may be insufficient to cause a discernible change in T3 concentration. Furthermore, the observed effect of breeding location on feather T3 concentration might have obscured any effect of Hg.
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Affiliation(s)
- Jonathan M Branco
- Departmento de Ecologia, Universidade de São Paulo - Rua Do Matão, 321 - Trav. 14, São Paulo, SP, CEP 05508090, Brazil.
| | - Erika Hingst-Zaher
- Museu Biologico, Instituto Butantan - Av Vital Brasil 1500, São Paulo, SP, CEP 05503-900, Brazil
| | - Danielle Dillon
- Department of Biological Sciences, Northern Arizona University - 617 S Beaver, Flagstaff, AZ, 86011, USA
| | - Renee Jordan-Ward
- Department of Biological Sciences, Northern Arizona University - 617 S Beaver, Flagstaff, AZ, 86011, USA
| | - Joe Siegrist
- Purple Martin Conservation Association - 301 Peninsula Drive, Suite 6 Erie, PA, 16505, USA
| | - Jason D Fischer
- Disney's Animals, Science and Environment, Lake Buena Vista, FL, 32830, USA
| | - Luis Schiesari
- Escola de Artes, Ciências e Humanidades, Universidade de São Paulo, Rua Arlindo Bettio, 1000, São Paulo, SP, CEP 03828-000, Brazil
| | - Frank A von Hippel
- Department of Community, Environment and Policy, University of Arizona - 1295 N. Martin Avenue, Tucson, AZ, 85724, USA
| | - C Loren Buck
- Department of Biological Sciences, Northern Arizona University - 617 S Beaver, Flagstaff, AZ, 86011, USA
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Wong CH, Tsai MA, Ko FC, Wang JH, Xue YJ, Yang WC. Skin Cortisol and Acoustic Activity: Potential Tools to Evaluate Stress and Welfare in Captive Cetaceans. Animals (Basel) 2023; 13:ani13091521. [PMID: 37174558 PMCID: PMC10177183 DOI: 10.3390/ani13091521] [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: 01/31/2023] [Revised: 04/05/2023] [Accepted: 04/26/2023] [Indexed: 05/15/2023] Open
Abstract
As people's focus broadens from animals on farms to zoos and aquaria, the field of welfare science and the public's concern for animal welfare continue to grow. In captive animals, stress and its causes are topics of interest in welfare issues, and the identification of an objective method that can be used to assess animals' stress as a physiological state is essential. Both behavioral and physiological parameters can be used as indicators in order to assess animal stress quantitatively. To validate this approach, acoustic activity and the sloughed scrape skin cortisol concentration were used to evaluate the animal welfare of captive beluga whales (Delphinapterus leucas). The acoustic activity (5 min at 10:00 am) of three captive D. leucas was routinely recorded by a transducer and analyzed using audio editing software. The calls were separated into three main categories: whistles, pulses, and combo calls. The sloughed scrape skin samples were collected non-invasively once a week from all three animals' fluke and/or flipper. Cortisol was extracted using a modified skin steroid extraction technique, and detected via commercially available enzyme immunoassays. The results showed that the cortisol concentration increased by varying levels when the whales encountered the same event. In addition, the number and distribution of the calls changed along with the events. This indicated that the changes in the cortisol concentration and acoustic behavior may have reflected the fluctuations in the environment and body condition. Therefore, the scrape cortisol measurement and acoustic recordings could be used to monitor stress levels in captive beluga whales. We recommend that aquaria consider incorporating skin scrape cortisol and acoustic activity monitoring into their standards for animal welfare.
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Affiliation(s)
- Chung-Hei Wong
- School of Veterinary Medicine, National Taiwan University, Taipei 106, Taiwan
| | - Ming-An Tsai
- Collage of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung 912, Taiwan
- National Museum of Marine Biology and Aquarium, Pingtung 944, Taiwan
| | - Fung-Chi Ko
- National Museum of Marine Biology and Aquarium, Pingtung 944, Taiwan
- Institute of Marine Biology, National Dong-Hwa University, Pingtung 944, Taiwan
| | - Jiann-Hsiung Wang
- College of Veterinary Medicine, National Chiayi University, Chiayi 600, Taiwan
| | - Yi-Jing Xue
- College of Veterinary Medicine, National Chiayi University, Chiayi 600, Taiwan
| | - Wei-Cheng Yang
- School of Veterinary Medicine, National Taiwan University, Taipei 106, Taiwan
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6
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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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7
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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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Fabio Braga A, E Hunt K, Dillon D, Minicozzi M, C Nicol S, Buck CL. Can spines tell a story? Investigation of echidna spines as a novel sample type for hormone analysis in monotremes. Gen Comp Endocrinol 2022; 325:114053. [PMID: 35580688 DOI: 10.1016/j.ygcen.2022.114053] [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: 08/14/2021] [Revised: 05/11/2022] [Accepted: 05/12/2022] [Indexed: 11/04/2022]
Abstract
The short-beaked echidna (Tachyglossus aculeatus) is a monotreme endemic to Australia and New Guinea, and is the most widespread native mammal in Australia. Despite its abundance, there are considerable gaps in our understanding of echidna life history such as reproductive cycles in both sexes, patterns of stress physiology, and possible seasonal changes in metabolism. Slow-growing integumentary sample types comprised of keratin (hair, claw, etc.) have been used in other wildlife to assess these questions via analysis of longitudinal patterns in steroid and thyroid hormones that are deposited in these tissues as they grow. Hairs and spines comprise the pelage of echidnas, the spines being keratinized structures homologous to hair. Thus, echidna spines could be a viable sample type for hormone analysis contributing to a better understanding of the biology of echidnas. The aim of this work was to determine whether steroid hormones are detectable in echidna spines, to perform assay validations, and to establish a protocol for extracting and quantifying hormones in echidna spines using commercially available assay kits. We also inspected cross-sectioned spines using light and electron microscopy for any evidence of annual growth markers that might enable inferences about spine growth rate. Corticosterone, progesterone, estradiol, and testosterone were detectable in all samples, and echidna spine extract passed standard assay validations (parallelism and accuracy), indicating that commercially available assay kits can quantify hormones accurately in this sample type. No visible growth marks were identified in the spines and thus spine growth rate is currently unknown. Echidna spines show promise as a novel matrix from which hormones can be quantified; next steps should involve determination of spine annual growth rate, possible seasonal changes in growth rate, and persistence of spines over time in order to perform physiological validations, i.e., relationship between physiological status and hormone concentrations in spines.
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Affiliation(s)
- Ana Fabio Braga
- Department of Biological Sciences, Northern Arizona University, 617 S. Beaver St., 86011 Flagstaff, AZ, USA.
| | - Kathleen E Hunt
- Smithsonian-Mason School of Conservation & Department of Biology, George Mason University, 1500 Remount Rd, Front Royal, VA 22630, USA
| | - Danielle Dillon
- Department of Biological Sciences, Northern Arizona University, 617 S. Beaver St., 86011 Flagstaff, AZ, USA
| | - Michael Minicozzi
- Department of Biological Sciences, Northern Arizona University, 617 S. Beaver St., 86011 Flagstaff, AZ, USA
| | - Stewart C Nicol
- School of Natural Sciences, University of Tasmania, Hobart, Tasmania, Australia
| | - C Loren Buck
- Department of Biological Sciences, Northern Arizona University, 617 S. Beaver St., 86011 Flagstaff, AZ, USA
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9
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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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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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Melica V, Atkinson S, Gendron D, Calambokidis J, Mueter F. Blubber endocrine profiles provide insights into reproductive biology in blue whales from the eastern North Pacific Ocean. Gen Comp Endocrinol 2021; 310:113830. [PMID: 34087186 PMCID: PMC9167553 DOI: 10.1016/j.ygcen.2021.113830] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 05/26/2021] [Accepted: 05/31/2021] [Indexed: 01/07/2023]
Abstract
The goal of the present study was to complement existing data of testosterone and progesterone in blue whale (Balaenoptera musculus) blubber from the eastern North Pacific Ocean to evaluate effects of seasonality and location on these hormones and to better assess reproductive status of individuals. Physiological parameters regarding reproduction are fundamental for describing population dynamics, and hormones can be a valid tool to estimate those for wildlife populations. In this study, blubber tissue was validated for testosterone and progesterone assays. Hormone concentrations were measured in 69 (35 males and 34 females) blubber samples from live (n = 66) and stranded (n = 3) animals collected between 2002 and 2016 from a known winter reproductive ground in the Gulf of California (GoC) and summer feeding areas along the United States West Coast (USWC), specifically off the states of California and Oregon. Results were combined with sighting histories as a tool to determine reproductive status of individual whales. Testosterone concentrations in adult male blue whales were significantly higher (p < 0.05) in blubber biopsies sampled off the USWC between the months of June and November compared to those sampled in the GoC between February and April. Elevated testosterone concentrations likely indicate physiological preparation for reproductive activity while the animals were present off the USWC. Progesterone concentrations were significantly elevated in pregnant females, confirming progesterone as an indicator of pregnancy in blue whales. Probabilities of being pregnant were estimated for adult females with unknown sighting histories based on progesterone concentrations. Testosterone in females was detected and measured only in pregnant whales suggesting its biosynthesis or metabolism is altered during gestation. These results provide updated and new information on the reproductive cycle of blue whales in the eastern North Pacific, posing new milestones to better estimate the timing of the mating season for this endangered population.
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Affiliation(s)
- Valentina Melica
- University of Alaska Fairbanks, College of Fisheries and Ocean Sciences, Fisheries Dept, Juneau Center, 17101 Pt. Lena Loop Road, Juneau, AK 99801, USA.
| | - Shannon Atkinson
- University of Alaska Fairbanks, College of Fisheries and Ocean Sciences, Fisheries Dept, Juneau Center, 17101 Pt. Lena Loop Road, Juneau, AK 99801, USA.
| | - Diane Gendron
- Centro Interdisciplinario de Ciencias Marina (IPN-CICIMAR), Av. Instituto Politecnico Nacional s/n, playa Palo de Santa Rita, 23096 La Paz, B.C.S., Mexico
| | | | - Franz Mueter
- University of Alaska Fairbanks, College of Fisheries and Ocean Sciences, Fisheries Dept, Juneau Center, 17101 Pt. Lena Loop Road, Juneau, AK 99801, USA
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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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Melica V, Atkinson S, Calambokidis J, Lang A, Scordino J, Mueter F. Application of endocrine biomarkers to update information on reproductive physiology in gray whale (Eschrichtius robustus). PLoS One 2021; 16:e0255368. [PMID: 34343192 PMCID: PMC8330940 DOI: 10.1371/journal.pone.0255368] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Accepted: 07/14/2021] [Indexed: 11/18/2022] Open
Abstract
Most of our knowledge on reproductive biology of gray whales dates back to scientific research conducted during commercial whaling in the late 1950s and 1960s. The goal of the present study was to provide updated insights on reproductive physiology of gray whales, using progesterone and testosterone as biomarkers. We measured hormone concentrations using enzyme immunoassay (EIA) techniques in blubber biopsies collected from 106 individual whales from March to November over a span of 12 years (2004-2016) between California and Alaska. We found testosterone concentrations in males to increase significantly with age (P = 0.03). Adult males showed significantly elevated testosterone concentrations when sampled in the fall compared to the summer (P = 0.01), likely indicating physiological preparation for mating. We measured testosterone concentrations in females of different age classes, but no statistical differences were found. We found significantly higher progesterone concentrations in pregnant females compared to non-pregnant females and adult males (P< 0.001), indicating progesterone is a valid biomarker for pregnancy in gray whales. Both female and male calves had elevated progesterone concentrations, suggesting maternal transfer via lactation. We fit a mixture of two normal distributions to progesterone data from all non-calf females to identify clusters of high and low progesterone and estimated the probability of being pregnant for whales of unknown reproductive status. With this approach we identified likely pregnant and non-pregnant animals. This study represents an important milestone on reproductive profiles in this population, that can be used to estimate more accurate and precise reproductive parameters to be used for better understanding population dynamics of gray whales.
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Affiliation(s)
- Valentina Melica
- Fisheries Department, College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Juneau, Alaska, United States of America
- * E-mail:
| | - Shannon Atkinson
- Fisheries Department, College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Juneau, Alaska, United States of America
| | | | - Aimée Lang
- Ocean Associates Inc., on Contract to NOAA Southwest Fisheries Science Center, La Jolla, California, United States of America
| | - Jonathan Scordino
- Marine Mammal Program, Makah Fisheries Management, Neah Bay, Washington, United States of America
| | - Franz Mueter
- Fisheries Department, College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Juneau, Alaska, United States of America
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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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15
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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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16
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Jaschke N, Sipos W, Hofbauer LC, Rachner TD, Rauner M. Skeletal endocrinology: where evolutionary advantage meets disease. Bone Res 2021; 9:28. [PMID: 34050126 PMCID: PMC8163738 DOI: 10.1038/s41413-021-00149-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 02/16/2021] [Accepted: 02/23/2021] [Indexed: 02/06/2023] Open
Abstract
The regulation of whole-body homeostasis by the skeleton is mediated by its capacity to secrete endocrine signaling molecules. Although bone-derived hormones confer several adaptive benefits, their physiological functions also involve trade-offs, thus eventually contributing to disease. In this manuscript, we discuss the origins and functions of two of the best-studied skeletal mediators, fibroblast growth factor 23 and osteocalcin, in an evolutionary context. Moreover, we provide a theoretical framework seeking to explain the broad involvement of these two hormones in amniote physiology as well as their potential to fuel the development and progression of diseases. Vice versa, we outline which perturbations might be amenable to manipulation of these systems and discuss limitations and ongoing challenges in skeletal endocrine research. Finally, we summarize unresolved questions and potential future studies in this thriving field.
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Affiliation(s)
- Nikolai Jaschke
- Department of Medicine III & Center for Healthy Aging, Technische Universität Dresden, Dresden, Germany
| | - Wolfgang Sipos
- Clinical Department for Farm Animals, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Lorenz C Hofbauer
- Department of Medicine III & Center for Healthy Aging, Technische Universität Dresden, Dresden, Germany
| | - Tilman D Rachner
- Department of Medicine III & Center for Healthy Aging, Technische Universität Dresden, Dresden, Germany
| | - Martina Rauner
- Department of Medicine III & Center for Healthy Aging, Technische Universität Dresden, Dresden, Germany.
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17
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Jaschke N, Wang A, Hofbauer LC, Rauner M, Rachner TD. Late-onset hypogonadism: Clinical evidence, biological aspects and evolutionary considerations. Ageing Res Rev 2021; 67:101301. [PMID: 33610812 DOI: 10.1016/j.arr.2021.101301] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 11/23/2020] [Accepted: 02/15/2021] [Indexed: 12/15/2022]
Abstract
The growing life expectancy in modern societies has raised scientific interest in identifying medical interventions to alleviate age-associated pathologies such as vascular calcification, cognitive decline, sarcopenia, osteoporosis and sexual dysfunction. Although no such single treatment has thus far been established in humans, some clinicians and patients have set their hopes on testosterone replacement therapy (TRT) as a potential "fountain of youth" for aging men. While TRT has proven effective in ameliorating distinct symptoms of late-onset hypogonadism (LOH), its safety remains to be demonstrated. Besides humans, multiple other species exhibit age-related reductions in circulating testosterone levels, raising the question whether such changes are an inherent, pathological feature of growing organismal age or rather reflect an adaptive response. In this manuscript, we apply key principles of evolutionary medicine to testosterone biology and LOH to provide a novel perspective on these two fields. Additionally, we discuss insightful data derived from the animal kingdom to illustrate the plasticity of individual testosterone trajectories across the lifespan, outline cost-benefit-considerations of TRT in LOH and highlight potential caveats of such therapies.
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Affiliation(s)
- Nikolai Jaschke
- Department of Medicine III & Center for Healthy Aging, Technische Universität Dresden, Dresden, Germany.
| | - Andrew Wang
- Department of Medicine (Rheumatology, Allergy & Immunology), Yale University School of Medicine, New Haven, CT, USA; Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA
| | - Lorenz C Hofbauer
- Department of Medicine III & Center for Healthy Aging, Technische Universität Dresden, Dresden, Germany
| | - Martina Rauner
- Department of Medicine III & Center for Healthy Aging, Technische Universität Dresden, Dresden, Germany
| | - Tilman D Rachner
- Department of Medicine III & Center for Healthy Aging, Technische Universität Dresden, Dresden, Germany
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18
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Sherman KK, Beaulieu-McCoy NE, Wurster EL, Wells RS, Smith CR, Barleycorn AA, Allen JB, Kellar NM. Serum correlation, demographic differentiation, and seasonality of blubber testosterone in common bottlenose dolphins, Tursiops truncatus, in Sarasota Bay, FL. Sci Rep 2021; 11:8941. [PMID: 33903714 PMCID: PMC8076180 DOI: 10.1038/s41598-021-88602-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 04/07/2021] [Indexed: 01/22/2023] Open
Abstract
Blubber and serum testosterone levels were compared among 55 individual common bottlenose dolphins, Tursiops truncatus, in Sarasota Bay, FL during 2011–2019. A significant positive relationship between the matrices was found in male testosterone concentrations in 29 paired samples (r2 = 0.932). Mature males (n = 17) had 300 times greater mean testosterone concentration in serum than immature males (n = 17). A comparison of blubber samples, including 12 females, 24 immature males, and 19 mature males, revealed significant differences in mean blubber testosterone values among all three demographics. Immature males had greater than 6 times the average blubber testosterone concentration of females and mature males had almost 100 times that of immature males. Estimated testis volume was highly correlated with blubber testosterone concentration and mature males had 60 times greater average testis volume than immature males. We observed seasonal variation in blubber testosterone in mature males, consistent with known reproductive patterns. These data suggest males can be distinguished from females and designated as mature or immature via blubber testosterone concentrations, an observation that validates dart biopsy sampling as a means of obtaining demographic data.
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Affiliation(s)
- Kathryn K Sherman
- Environmental Assessment Services, LLC, Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 8901 La Jolla Shores Drive, La Jolla, CA, 92037, USA.
| | - Nicole E Beaulieu-McCoy
- Volunteer With Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 8901 La Jolla Shores Drive, La Jolla, CA, 92037, USA
| | - Elyse L Wurster
- Environmental Assessment Services, LLC, Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 8901 La Jolla Shores Drive, La Jolla, CA, 92037, USA
| | - Randall S Wells
- Chicago Zoological Society's Sarasota Dolphin Research Program, c/o Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL, 34236, USA
| | - Cynthia R Smith
- National Marine Mammal Foundation, 2240 Shelter Island Drive, Suite 200, San Diego, CA, 92106, USA
| | - Aaron A Barleycorn
- Chicago Zoological Society's Sarasota Dolphin Research Program, c/o Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL, 34236, USA
| | - Jason B Allen
- Chicago Zoological Society's Sarasota Dolphin Research Program, c/o Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL, 34236, USA
| | - Nicholas M Kellar
- Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 8901 La Jolla Shores Drive, La Jolla, CA, 92037, USA
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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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20
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Pokharel SS, Yoneda H, Yanagi M, Sukumar R, Kinoshita K. The tail-tale of stress: an exploratory analysis of cortisol levels in the tail-hair of captive Asian elephants. PeerJ 2021; 9:e10445. [PMID: 33505782 PMCID: PMC7789861 DOI: 10.7717/peerj.10445] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 11/07/2020] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Assessment of physiological states by measuring biomarkers, such as cortisol, has significantly contributed to the monitoring of health, welfare and management of animals. Immunoreactive cortisol in hair (hC) has been used widely for deciphering 'stressful' past-events in various wild and captive animals. However, no such studies have been done in long-lived mammals. METHODS In this first exploratory study in elephants, we assessed (i) tail-hair growth rate (TGR) and (ii) hC levels in tail-hair samples from six captive Asian elephants from two zoos in Japan for comparing hC levels with zoo-keepers' records of distinct biological events over a c.0.5-2.0-year period. Tail-hair samples were cut into segments (based on monthly growth rate), pulverized or minced and a validated cortisol enzyme-immunoassay employed to measure hC levels. RESULTS When the hC levels of all individuals were compared with the keepers' records, a posteriori, most of the high hC levels were found to be associated with 'stressful' or distinct behavioural events such as pathological (anaemia, colic infection, skin infection, oral sores), psychosocial (reluctance in entering the enclosure, presence of a calf) and husbandry practice-related (contact trials/ space sharing) conditions, indicating that tail-hair indeed can be a potential 'retrospective' calendar of physiological health of an animal. CONCLUSIONS Our observations open up the possibility of using the tail-hair as an alternative matrix to reconstruct the physiological history of elephants.
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Affiliation(s)
- Sanjeeta Sharma Pokharel
- Wildlife Research Center, Kyoto University, Kyoto, Japan
- Centre for Ecological Sciences, Indian Institute of Science, Bangalore, Karnataka, India
| | | | - Moe Yanagi
- Wildlife Research Center, Kyoto University, Kyoto, Japan
| | - Raman Sukumar
- Centre for Ecological Sciences, Indian Institute of Science, Bangalore, Karnataka, India
- Institute for Advanced Study, Kyoto University, Kyoto, Japan
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21
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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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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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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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Gormally BMG, Romero LM. What are you actually measuring? A review of techniques that integrate the stress response on distinct time‐scales. Funct Ecol 2020. [DOI: 10.1111/1365-2435.13648] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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25
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Szesciorka AR, Ballance LT, Širović A, Rice A, Ohman MD, Hildebrand JA, Franks PJS. Timing is everything: Drivers of interannual variability in blue whale migration. Sci Rep 2020; 10:7710. [PMID: 32382054 PMCID: PMC7206123 DOI: 10.1038/s41598-020-64855-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 04/17/2020] [Indexed: 12/17/2022] Open
Abstract
Blue whales need to time their migration from their breeding grounds to their feeding grounds to avoid missing peak prey abundances, but the cues they use for this are unknown. We examine migration timing (inferred from the local onset and cessation of blue whale calls recorded on seafloor-mounted hydrophones), environmental conditions (e.g., sea surface temperature anomalies and chlorophyll a), and prey (spring krill biomass from annual net tow surveys) during a 10 year period (2008-2017) in waters of the Southern California Region where blue whales feed in the summer. Colder sea surface temperature anomalies the previous season were correlated with greater krill biomass the following year, and earlier arrival by blue whales. Our results demonstrate a plastic response of blue whales to interannual variability and the importance of krill as a driving force behind migration timing. A decadal-scale increase in temperature due to climate change has led to blue whales extending their overall time in Southern California. By the end of our 10-year study, whales were arriving at the feeding grounds more than one month earlier, while their departure date did not change. Conservation strategies will need to account for increased anthropogenic threats resulting from longer times at the feeding grounds.
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Affiliation(s)
- Angela R Szesciorka
- Scripps Institution of Oceanography, UC San Diego, 9500 Gilman Dr., La Jolla, CA, 92093, US.
| | - Lisa T Ballance
- Scripps Institution of Oceanography, UC San Diego, 9500 Gilman Dr., La Jolla, CA, 92093, US.,Southwest Fisheries Science Center, NOAA Fisheries Service, 8901 La Jolla Shores Dr., La Jolla, CA, 92037, US.,Oregon State University, Marine Mammal Institute, 2030 SE Marine Science Dr., Newport, Oregon, 97365, US
| | - Ana Širović
- Texas A&M University at Galveston, 200 Seawolf Parkway, Galveston, TX, 77554, US
| | - Ally Rice
- Scripps Institution of Oceanography, UC San Diego, 9500 Gilman Dr., La Jolla, CA, 92093, US
| | - Mark D Ohman
- Scripps Institution of Oceanography, UC San Diego, 9500 Gilman Dr., La Jolla, CA, 92093, US
| | - John A Hildebrand
- Scripps Institution of Oceanography, UC San Diego, 9500 Gilman Dr., La Jolla, CA, 92093, US
| | - Peter J S Franks
- Scripps Institution of Oceanography, UC San Diego, 9500 Gilman Dr., La Jolla, CA, 92093, US
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Hunt KE, Robbins J, Buck CL, Bérubé M, Rolland RM. Evaluation of fecal hormones for noninvasive research on reproduction and stress in humpback whales (Megaptera novaeangliae). Gen Comp Endocrinol 2019; 280:24-34. [PMID: 30951726 DOI: 10.1016/j.ygcen.2019.04.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Revised: 03/22/2019] [Accepted: 04/01/2019] [Indexed: 01/05/2023]
Abstract
Fecal hormone analysis shows high potential for noninvasive assessment of population-level patterns in stress and reproduction of marine mammals. However, the marine environment presents unique challenges for fecal sample collection. Data are still lacking on collection methodology and assay validations for most species, particularly for those mysticete whales that have variable diets. In this study we tested collection techniques for fecal samples of free-swimming humpback whales (Megaptera novaeangliae), and validated immunoassays for five steroid and thyroid hormones. Resulting data were used for preliminary physiological validations, i.e., comparisons to independently confirmed sex and reproductive state. Pregnant females had significantly higher fecal progestins and glucocorticoids than did other demographic categories of whales. Two possible cases of previously undetected pregnancies were noted. Males had significantly higher fecal testosterone metabolites than nonpregnant females. Fecal glucocorticoids were significantly elevated in pregnant females and mature males compared to nonpregnant females. Calf fecal samples had elevated concentrations of all fecal hormones. Fecal thyroid hormones showed a significant seasonal decline from spring to summer. Though sample sizes were small, and sampling was necessarily opportunistic, these patterns indicate that noninvasive fecal hormone analysis may facilitate studies of reproduction, stress and potentially energetics in humpback whales.
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Affiliation(s)
- Kathleen E Hunt
- Anderson Cabot Center for Ocean Life, New England Aquarium, Central Wharf, New England, Boston, MA 02110, USA; Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA.
| | - Jooke Robbins
- Center for Coastal Studies, 5 Holway Avenue, Provincetown, MA 02657, USA
| | - C Loren Buck
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Martine Bérubé
- Center for Coastal Studies, 5 Holway Avenue, Provincetown, MA 02657, USA; Marine Evolution and Conservation, Groningen Institute of Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Rosalind M Rolland
- Anderson Cabot Center for Ocean Life, New England Aquarium, Central Wharf, New England, Boston, MA 02110, USA
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