1
|
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.
Collapse
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
| |
Collapse
|
2
|
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.
Collapse
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
| |
Collapse
|
3
|
Mansouri F, Winfield ZC, Crain DD, Morris B, Charapata P, Sabin R, Potter CW, Hering AS, Fulton J, Trumble SJ, Usenko S. Evidence of multi-decadal behavior and ecosystem-level changes revealed by reconstructed lifetime stable isotope profiles of baleen whale earplugs. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 757:143985. [PMID: 33321341 DOI: 10.1016/j.scitotenv.2020.143985] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 11/11/2020] [Accepted: 11/14/2020] [Indexed: 06/12/2023]
Abstract
Biological time series datasets provide an unparalleled opportunity to investigate regional and global changes in the marine environment. Baleen whales are long-lived sentinel species and an integral part of the marine ecosystem. Increasing anthropogenic terrestrial and marine activities alter ocean systems, and such alterations could change foraging and feeding behavior of baleen whales. In this study, we analyzed δ13C and δ15N of baleen whale earplugs from three different species (N = 6 earplugs, n = 337 laminae) to reconstruct the first continuous stable isotope profiles with a six-month resolution. Results of our study provide an unprecedented opportunity to assess behavioral as well as ecological changes. Abrupt shifts and temporal variability observed in δ13C and δ15N profiles could be indicative of behavior change such as shift in foraging location and/or trophic level in response to natural or anthropogenic disturbances. Additionally, five out of six individuals demonstrated long-term declining trends in δ13C profiles, which could suggest influence of emission of depleted 13CO2 from fossil fuel combustion referred to as the Suess effect. After adjusting the δ13C values of earplugs for the estimated Suess effect and re-evaluating δ13C profiles, significant decline in δ13C values as well as different rate of depletion suggest contribution of other sources that could impact δ13C values at the base of the food web.
Collapse
Affiliation(s)
- Farzaneh Mansouri
- Department of Environmental Science, Baylor University, Waco, TX 76706, USA
| | - Zach C Winfield
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX 76706, USA
| | | | - Brooke Morris
- Department of Biology, Baylor University, Waco, TX 76706, USA
| | | | - Richard Sabin
- Division of Vertebrates, Department of Life Sciences, Natural History Museum, London SW7 5BD, UK
| | - Charles W Potter
- Department of Vertebrate Zoology, Smithsonian Institution National Museum of Natural History, Washington, DC 20013, USA
| | - Amanda S Hering
- Department of Statistical Science, Baylor University, Waco, TX 76706, USA
| | - James Fulton
- Department of Geoscience, Baylor University, Waco, TX 76706, USA
| | | | - Sascha Usenko
- Department of Environmental Science, Baylor University, Waco, TX 76706, USA; Department of Chemistry and Biochemistry, Baylor University, Waco, TX 76706, USA; Department of Biology, Baylor University, Waco, TX 76706, USA.
| |
Collapse
|
4
|
Crain DD, Karpovich SA, Quakenbush L, Polasek L. Using claws to compare reproduction, stress and diet of female bearded and ringed seals in the Bering and Chukchi seas, Alaska, between 1953-1968 and 1998-2014. CONSERVATION PHYSIOLOGY 2021; 9:coaa115. [PMID: 33442472 PMCID: PMC7786451 DOI: 10.1093/conphys/coaa115] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/27/2020] [Accepted: 11/20/2020] [Indexed: 05/08/2023]
Abstract
Rapid climate warming is decreasing sea ice thickness, extent and duration. Marine mammals such as bearded (Erignathus barbatus) and ringed (Pusa hispida) seals, which use sea ice for pupping, molting and resting, may be negatively affected. Claws from bearded and ringed seals store up to 14 and 12 years of sequential analyte data, respectively. These data can be used to compare reproduction, stress and diet across decades. In this study, we compare progesterone, cortisol and carbon and nitrogen stable isotopes in female bearded and ringed seals during 1953-1968 (pre-1968, a period prior to sea ice decline) to 1998-2014 (post-1998, a period during sea ice decline). When comparing these periods, bearded seals had statistically higher cortisol concentrations post-1998, and for both species δ13C was more negative post-1998, while progesterone and δ15N did not change. There was a positive relationship between progesterone and cortisol Z-scores for both species, except for ringed seals post-1998. There was a negative relationship between cortisol Z-scores and δ13C for bearded seals evident in post-1998 indicating that higher cortisol Z-scores are associated with more negative δ13C in bearded seals in recent years. This negative relationship between cortisol and δ13C in bearded seals suggests a shift to higher prey diversity, possibly due to changes in sea ice in the Pacific Arctic evident post 1998. Progesterone Z-scores corresponded to expected differences among non-pregnant, unimplanted, implanted and post-partum individuals. Using these data, pregnancy history was determined for reproductive years for each individual female sampled, which could allow for yearly pregnancy rates to be calculated given a large enough representative sample of the population. These results combine decades of observational studies with hormones and stable isotopes to infer changes in reproduction, stress and diet, as well as the connection between these life history parameters.
Collapse
Affiliation(s)
| | - Shawna A Karpovich
- Alaska Department of Fish and Game, 1300 College Road, Fairbanks, AK 99701, USA
| | - Lori Quakenbush
- Alaska Department of Fish and Game, 1300 College Road, Fairbanks, AK 99701, USA
| | - Lori Polasek
- Alaska Department of Fish and Game, 1255 W 8 St, Juneau, AK 99802, USA
| |
Collapse
|
5
|
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.
Collapse
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
| |
Collapse
|