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Pallin LJ, Garrigue C, Kellar NM, Baker CS, Bonneville CD, Derville S, Garland EC, Steel D, Friedlaender AS. Demographic and physiological signals of reproductive events in humpback whales on a southwest pacific breeding ground. CONSERVATION PHYSIOLOGY 2024; 12:coae038. [PMID: 38894754 PMCID: PMC11184982 DOI: 10.1093/conphys/coae038] [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: 12/21/2023] [Revised: 04/15/2024] [Accepted: 06/08/2024] [Indexed: 06/21/2024]
Abstract
The field of marine mammal conservation has dramatically benefited from the rapid advancement of methods to assess the reproductive physiology of individuals and populations from steroid hormones isolated from minimally invasive skin-blubber biopsy samples. Historically, this vital information was only available from complete anatomical and physiological investigations of samples collected during commercial or indigenous whaling. Humpback whales (Megaptera novaeangliae) are a migratory, cosmopolitan species that reproduce in warm, low-latitude breeding grounds. New Caledonia is seasonally visited by a small breeding sub-stock of humpback whales, forming part of the endangered Oceania subpopulation. To better understand the demographic and seasonal patterns of reproductive physiology in humpback whales, we quantified baseline measurements of reproductive hormones (progesterone-P4, testosterone-T and 17β-estradiol-E2) using an extensive archive of skin-blubber biopsy samples collected from female humpback whales in New Caledonia waters between 2016 and 2019 (n = 194). We observed significant differences in the P4, T and E2 concentrations across different demographic groups of female humpback whales, and we described some of the first evidence of the endocrine patterns of estrous in live free-ranging baleen whales. This study is fundamental in its methodological approach to a wild species that has a global distribution, with seasonally distinct life histories. This information will assist in monitoring, managing and conserving this population as global ecological changes continue to occur unhindered.
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Affiliation(s)
- Logan J Pallin
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Ocean Health Building, 115 McAllister Way, Santa Cruz, CA 95060, USA
- Department of Ocean Sciences, University of California Santa Cruz, Ocean Health Building, 115 McAllister Way, Santa Cruz, CA 95060, USA
| | - Claire Garrigue
- UMR ENTROPIE IRD, Université de La Réunion, Université de la Nouvelle-Calédonie, CNRS, IFREMER, Laboratoire d'excellence-CORAIL, 101 promenade Roger Laroque BP A5NOUMEA CEDEX5 Nouvelle Calédonie 98848, France
- Opération Cétacés, BP 12827, Nouvelle-Calédonie 98802, France
| | - Nicholas M Kellar
- Marine Mammal Turtle Division, , Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 8901 La Jolla Shores Drive, La Jolla, CA 92037, USA
| | - C Scott Baker
- Department of Fisheries, Wildlife, and Conservation Sciences, Marine Mammal Institute, Oregon State University, Hatfield Marine Science Center, 2030 SE Marine Science Drive, Newport, OR 97365, USA
| | - Claire D Bonneville
- UMR ENTROPIE IRD, Université de La Réunion, Université de la Nouvelle-Calédonie, CNRS, IFREMER, Laboratoire d'excellence-CORAIL, 101 promenade Roger Laroque BP A5NOUMEA CEDEX5 Nouvelle Calédonie 98848, France
- Opération Cétacés, BP 12827, Nouvelle-Calédonie 98802, France
| | - Solène Derville
- UMR ENTROPIE IRD, Université de La Réunion, Université de la Nouvelle-Calédonie, CNRS, IFREMER, Laboratoire d'excellence-CORAIL, 101 promenade Roger Laroque BP A5NOUMEA CEDEX5 Nouvelle Calédonie 98848, France
- Opération Cétacés, BP 12827, Nouvelle-Calédonie 98802, France
| | - Ellen C Garland
- Sea Mammal Research Unit, Scottish Oceans Institute, School of Biology, University of St. Andrews, W Sands Rd, St Andrews KY16 9XL, UK
| | - Debbie Steel
- Department of Fisheries, Wildlife, and Conservation Sciences, Marine Mammal Institute, Oregon State University, Hatfield Marine Science Center, 2030 SE Marine Science Drive, Newport, OR 97365, USA
| | - Ari S Friedlaender
- Department of Ocean Sciences, University of California Santa Cruz, Ocean Health Building, 115 McAllister Way, Santa Cruz, CA 95060, USA
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Fernandez Ajó A, Pirotta E, Bierlich KC, Hildebrand L, Bird CN, Hunt KE, Buck CL, New L, Dillon D, Torres LG. Assessment of a non-invasive approach to pregnancy diagnosis in gray whales through drone-based photogrammetry and faecal hormone analysis. ROYAL SOCIETY OPEN SCIENCE 2023; 10:230452. [PMID: 37476509 PMCID: PMC10354484 DOI: 10.1098/rsos.230452] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 06/26/2023] [Indexed: 07/22/2023]
Abstract
Knowledge of baleen whales' reproductive physiology is limited and requires long-term individual-based studies and innovative tools. We used 6 years of individual-level data on the Pacific Coast Feeding Group gray whales to evaluate the utility of faecal progesterone immunoassays and drone-based photogrammetry for pregnancy diagnosis. We explored the variability in faecal progesterone metabolites and body morphology relative to observed reproductive status and estimated the pregnancy probability for mature females of unknown reproductive status using normal mixture models. Individual females had higher faecal progesterone concentrations when pregnant than when presumed non-pregnant. Yet, at the population level, high overlap and variability in progesterone metabolite concentrations occurred between pregnant and non-pregnant groups, limiting this metric for accurate pregnancy diagnosis in gray whales. Alternatively, body width at 50% of the total body length (W50) correctly discriminated pregnant from non-pregnant females at individual and population levels, with high accuracy. Application of the model using W50 metric to mature females of unknown pregnancy status identified eight additional pregnancies with high confidence. Our findings highlight the utility of drone-based photogrammetry to non-invasively diagnose pregnancy in this group of gray whales, and the potential for improved data on reproductive rates for population management of baleen whales generally.
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Affiliation(s)
- A. Fernandez Ajó
- Geospatial Ecology of Marine Megafauna Lab, Marine Mammal Institute, Department of Fisheries, Wildlife and Conservation Sciences, Oregon State University, Newport 97365, OR, USA
| | - E. Pirotta
- Centre for Research into Ecological and Environmental Modelling, University of St Andrews, St Andrews, UK
| | - K. C. Bierlich
- Geospatial Ecology of Marine Megafauna Lab, Marine Mammal Institute, Department of Fisheries, Wildlife and Conservation Sciences, Oregon State University, Newport 97365, OR, USA
| | - L. Hildebrand
- Geospatial Ecology of Marine Megafauna Lab, Marine Mammal Institute, Department of Fisheries, Wildlife and Conservation Sciences, Oregon State University, Newport 97365, OR, USA
| | - C. N. Bird
- Geospatial Ecology of Marine Megafauna Lab, Marine Mammal Institute, Department of Fisheries, Wildlife and Conservation Sciences, Oregon State University, Newport 97365, OR, USA
| | - K. E. Hunt
- Smithsonian-Mason School of Conservation, Department of Biology, George Mason University, 1500 Remount Road, Front Royal, VA 22630, USA
| | - C. L. Buck
- Department of Biological Sciences, Northern Arizona University, 617 South Beaver Street, Flagstaff, AZ 86011, USA
| | - L. New
- Ursinus College, 601 East Main Street, Collegeville, PA 19426, USA
| | - D. Dillon
- Department of Biological Sciences, Northern Arizona University, 617 South Beaver Street, Flagstaff, AZ 86011, USA
| | - L. 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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3
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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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Xu Y, Jiang D, Liu J, Fu Y, Song Y, Fan D, Huang X, Liufu S, Pan J, Ouyang H, Tian Y, Shen X, Huang Y. Photoperiodic Changes in Both Hypothalamus Neurotransmitters and Circulating Gonadal Steroids Metabolomic Profiles in Relation to Seasonal Reproduction in Male Quail. Front Physiol 2022; 13:824228. [PMID: 35399254 PMCID: PMC8993408 DOI: 10.3389/fphys.2022.824228] [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: 11/29/2021] [Accepted: 01/31/2022] [Indexed: 11/17/2022] Open
Abstract
Both hypothalamic neurotransmitters and serum steroid hormones are impacted by photoperiod and have effects on physiology and seasonal reproductive. However, the relationship between circulating gonadal steroids and hypothalamic neurotransmitters underlying different photoperiod is still unclear. To further understand the crosstalk of neurotransmitters and steroids in seasonal reproduction, metabolic changes of 27 neurotransmitters concentrated in hypothalamus tissues and 42 steroids hormones in serum were assessed during two artificial photoperiodic programs. The results showed that photoperiod induce testicular atrophy and recrudescence. In L-to-S groups, significantly decreased levels of testosterone concentration were found in serum (P < 0.001) and increased 11-Dehydrocorticosterone (P < 0.05); Testosterone were almost undetectable at SD_14d. In addition, the hypothalamus exhibited significantly increased arginine and 4-aminobutyric acid (GABA) concentration and decreased serotonin and epinephrine content (P < 0.01 or P < 0.05). Accordingly, serum testosterone and androstenedione became detectable at LD_3d in the S-to-L group and were markedly increase at LD_7d. Furthermore, Serum androstenedione showed a significant increase with long light expose (P < 0.01). Additionally, the hypothalamus exhibited both significantly increased L.Tryptophan and phenylalanine concentration, as well as decreased L-glutamine and L-glutamine.acid content (P < 0.01 or P < 0.05). Serotonin metabolism showed significant differences between L-to-S group and S-to-L group. Furthermore, in the correlation analysis, serum testosterone had a positive correlation with 5-Hydroxyindole-3-acetic acid (5-HIAA), while Androstenedione was significantly negative with L.Tryptophan in L-to-S (P < 0.05). However, in S-to-L group, serum testosterone showed strong negative correlation with both serotonin and 5-HIAA (P < 0.05), but positive correlation with L.Tryptophan (P < 0.01), while Androstenedione was significantly negative correlation with both serotonin (P < 0.05) and L-Glutamine (P < 0.01). Photoperiod also had significant effects on the mRNA expression. We found significant differences in gene expression patterns of both serotonin signaling and steroid biosynthesis, while MAOB, NR5A1, and 3β-HSD showed an opposite tendency between two groups. Taken together, our results revealed that circulating gonadal steroids and hypothalamic neurotransmitters were significantly impact quail’s seasonal reproduction. Circulating gonadal steroids have different effects on neurotransmitter at different photoperiodism, which may coordinately influence the seasonal reproduction of quails.
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Affiliation(s)
- Yanglong Xu
- College of Animal Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, China.,Guangdong Province Key Laboratory of Waterfowl Healthy Breeding, Guangzhou, China
| | - Danli Jiang
- College of Animal Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, China.,Guangdong Province Key Laboratory of Waterfowl Healthy Breeding, Guangzhou, China
| | - Jiaxin Liu
- College of Animal Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, China.,Guangdong Province Key Laboratory of Waterfowl Healthy Breeding, Guangzhou, China
| | - Yuting Fu
- College of Animal Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, China.,Guangdong Province Key Laboratory of Waterfowl Healthy Breeding, Guangzhou, China
| | - Yan Song
- College of Animal Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, China.,Guangdong Province Key Laboratory of Waterfowl Healthy Breeding, Guangzhou, China
| | - Di Fan
- College of Animal Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, China.,Guangdong Province Key Laboratory of Waterfowl Healthy Breeding, Guangzhou, China
| | - Xuefei Huang
- College of Animal Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, China.,Guangdong Province Key Laboratory of Waterfowl Healthy Breeding, Guangzhou, China
| | - Sui Liufu
- College of Animal Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, China.,Guangdong Province Key Laboratory of Waterfowl Healthy Breeding, Guangzhou, China
| | - Jianqiu Pan
- College of Animal Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, China.,Guangdong Province Key Laboratory of Waterfowl Healthy Breeding, Guangzhou, China
| | - Hongjia Ouyang
- College of Animal Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, China.,Guangdong Province Key Laboratory of Waterfowl Healthy Breeding, Guangzhou, China
| | - Yunbo Tian
- College of Animal Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, China.,Guangdong Province Key Laboratory of Waterfowl Healthy Breeding, Guangzhou, China
| | - Xu Shen
- College of Animal Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, China.,Guangdong Province Key Laboratory of Waterfowl Healthy Breeding, Guangzhou, China
| | - Yunmao Huang
- College of Animal Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, China.,Guangdong Province Key Laboratory of Waterfowl Healthy Breeding, Guangzhou, China
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Dalle Luche G, Boggs ASP, Kucklick JR, Hawker DW, Wisse JH, Bengtson Nash S. Steroid hormone profiles and body conditions of migrating male humpback whales (Megaptera novaeangliae). Gen Comp Endocrinol 2021; 313:113888. [PMID: 34425085 DOI: 10.1016/j.ygcen.2021.113888] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 08/08/2021] [Accepted: 08/18/2021] [Indexed: 11/21/2022]
Abstract
Simultaneous analysis of multiple steroid hormones from remotely obtained blubber biopsies has the potential to concurrently provide information regarding stress and reproductive status from free-swimming cetaceans, while also investigating correlations between hormone concentrations and other health biomarkers. In this study we measured blubber concentration profiles of eight reproductive and adrenal steroid hormones (17α-hydroxy-progesterone, testosterone, androstenedione, progesterone, cortisol, 11-deoxy-corticosterone, oestrone, and oestradiol) together with body condition, as determined by the inverse Adipocyte Index, of 101 male humpback whales. Whales were sampled randomly at two time points, while migrating to and from their northeast Australian breeding grounds, allowing for intra- and inter-seasonal profile analysis. Testosterone, progesterone and cortisol together with androstenedione 17α-hydroxyprogesterone, and oestrone concentrations (the latter quantified for the first time in live biopsied male humpback whales) decreased between the northward and southward migrations. Decreasing testosterone levels during the height of humpback whale conceptions suggests asynchronicity between blubber testosterone levels and the expected peak of male fertility. Statistically significant relationships between levels of certain steroid analytes were observed and appeared to change between the early and late breeding seasons. During the northward migration, testosterone, progesterone, androstenedione, oestrone and 17α-hydroxyprogesterone levels were positively correlated. Cortisol concentrations correlated positively with those of testosterone during the northward migration, but negatively during the southward migration. Androstenedione and testosterone were positively correlated with adiposity during the late breeding season. These hormone-hormone and hormone-adiposity correlations may be reflective of the activation of certain steroid hormone synthesis pathways, or alternatively, of concomitant physiological stimuli. As steroid hormones work in concert, information on multiple steroid hormones is needed to interpret endocrinological status and understand the relationships between these compounds and ancillary health markers. This study provides steroid hormone profiles of wild male humpback whales, as well as the first insight into seasonal male endocrinology as a function of adiposity.
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Affiliation(s)
- Greta Dalle Luche
- Environmental Futures Research Institute, Griffith University, Brisbane, QLD 4111, Australia.
| | - Ashley S P Boggs
- National Institute of Standards and Technology, Hollings Marine Laboratory, Charleston, SC 29412, USA
| | - John R Kucklick
- National Institute of Standards and Technology, Hollings Marine Laboratory, Charleston, SC 29412, USA
| | - Darryl W Hawker
- School of Environment and Science, Griffith University, Brisbane, QLD 4111, Australia
| | - Jillian H Wisse
- Nicholas School of the Environment, Duke University, Durham, NC 27710, USA
| | - Susan Bengtson Nash
- Environmental Futures Research Institute, Griffith University, Brisbane, QLD 4111, Australia
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6
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Bengtson Nash SM, Casa MV, Kawaguchi S, Staniland I, Bjerregaard P. Mercury levels in humpback whales, and other Southern Ocean marine megafauna. MARINE POLLUTION BULLETIN 2021; 172:112774. [PMID: 34364143 DOI: 10.1016/j.marpolbul.2021.112774] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 07/23/2021] [Accepted: 07/24/2021] [Indexed: 06/13/2023]
Abstract
Mercury is a known potent neurotoxin. The biogeochemical cycle of mercury in the remote Antarctic region is still poorly understood, with Polar climate change contributing added complexity. Longitudinal biomonitoring of mercury accumulation in Antarctic marine megafauna can contribute top-down insight into the bio-physical drivers of wildlife exposure. The bioaccumulative nature of organic mercury renders high trophic predators at the greatest risk of elevated exposure. Humpback whales represent secondary consumers of the Antarctic sea-ice ecosystem and an ideal biomonitoring species for persistent and bioaccumulative compounds due to their extended life-spans. This study provides the first results of mercury accumulation in humpback whales, and places findings within the context of mercury accumulation in both prey, as well as six other species of Antarctic marine megafauna. Combined, these findings contribute new baseline information regarding mercury exposure to Antarctic wildlife, and highlights methodological prerequisites for routine mercury biomonitoring in wildlife via non-lethally biopsied superficial tissues.
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Affiliation(s)
- Susan M Bengtson Nash
- Centre for Planetary Health and Food Security, Griffith University, Nathan, QLD 4111, Australia.
| | - Maria Valeria Casa
- Centre for Planetary Health and Food Security, Griffith University, Nathan, QLD 4111, Australia
| | - So Kawaguchi
- Australian Antarctic Division, Kingston, TAS 7050, Australia
| | - Iain Staniland
- British Antarctic Survey, Cambridge CB3 0ET, England, United Kingdom of Great Britain and Northern Ireland
| | - Poul Bjerregaard
- Department of Biology, The University of Southern Denmark, 5230 Odense M, Denmark
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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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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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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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Kershaw JL, Ramp CA, Sears R, Plourde S, Brosset P, Miller PJO, Hall AJ. Declining reproductive success in the Gulf of St. Lawrence's humpback whales (Megaptera novaeangliae) reflects ecosystem shifts on their feeding grounds. GLOBAL CHANGE BIOLOGY 2020; 27:1027-1041. [PMID: 33368899 DOI: 10.1111/gcb.15466] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 11/17/2020] [Accepted: 11/17/2020] [Indexed: 06/12/2023]
Abstract
Climate change has resulted in physical and biological changes in the world's oceans. How the effects of these changes are buffered by top predator populations, and therefore how much plasticity lies at the highest trophic levels, are largely unknown. Here endocrine profiling, longitudinal observations of known individuals over 15 years between 2004 and 2018, and environmental data are combined to examine how the reproductive success of a top marine predator is being affected by ecosystem change. The Gulf of St. Lawrence, Canada, is a major summer feeding ground for humpback whales (Megaptera novaeangliae) in the North Atlantic. Blubber biopsy samples (n = 185) of female humpback whales were used to investigate variation in pregnancy rates through the quantification of progesterone. Annual pregnancy rates showed considerable variability, with no overall change detected over the study. However, a total of 457 photo-identified adult female sightings records with/without calves were collated, and showed that annual calving rates declined significantly. The probability of observing cow-calf pairs was related to favourable environmental conditions in the previous year; measured by herring spawning stock biomass, Calanus spp. abundance, overall copepod abundance and phytoplankton bloom magnitude. Approximately 39% of identified pregnancies were unsuccessful over the 15 years, and the average annual pregnancy rate was higher than the average annual calving rate at ~37% and ~23% respectively. Together, these data suggest that the declines in reproductive success could be, at least in part, the result of females being unable to accumulate the energy reserves necessary to maintain pregnancy and/or meet the energetic demands of lactation in years of poorer prey availability rather than solely an inability to become pregnant. The decline in calving rates over a period of major environmental variability may suggest that this population has limited resilience to such ecosystem change.
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Affiliation(s)
- Joanna L Kershaw
- Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, St Andrews, UK
- Mingan Island Cetacean Study, Saint Lambert, QC, Canada
| | - Christian A Ramp
- Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, St Andrews, UK
- Mingan Island Cetacean Study, Saint Lambert, QC, Canada
| | - Richard Sears
- Mingan Island Cetacean Study, Saint Lambert, QC, Canada
| | - Stéphane Plourde
- Department of Fisheries and Oceans Canada, Maurice Lamontagne Institute, Mont-Joli, QC, Canada
| | - Pablo Brosset
- Department of Fisheries and Oceans Canada, Maurice Lamontagne Institute, Mont-Joli, QC, Canada
- Laboratoire de Biologie Halieutique, Ifremer, Plouzané, France
- Laboratoire des Sciences de l'Environnement Marin - IUEM, Université de Brest - UMR 6539 CNRS/UBO/IRD/Ifremer, Plouzané, France
| | - Patrick J O Miller
- Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, St Andrews, UK
| | - Ailsa J Hall
- Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, St Andrews, UK
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