TY - JOUR
T1 - Multi-year patterns in testosterone, cortisol and corticosterone in baleen from adult males of three whale species
AU - Hunt, Kathleen E.
AU - Lysiak, Nadine S.J.
AU - Matthews, Cory J.D.
AU - Lowe, Carley
AU - Ajó, Alejandro Fernández
AU - Dillon, Danielle
AU - Willing, Cornelia
AU - Heide-Jørgensen, Mads Peter
AU - Ferguson, Steven H.
AU - Moore, Michael J.
AU - Loren Buck, C.
N1 - Funding Information:
This work was supported by (1) the Arizona Board of Regents Technology Research Initiative Fund; (2) the Center for Bioengineering Innovation at Northern Arizona University; (3) the Greenland Institute of Natural Resources; (4) the Woods Hole Oceanographic Institution Ocean Life Institute and (5) Fisheries and Ocean Canada’s (DFO) Priorities and Partnership Strategic Initiatives Fund and Oceans Protection Plan.
Funding Information:
Bowhead baleen from the legal Inuit subsistence hunt in Greenland was made available by the Greenland Institute of Natural Resources. Our thanks also to Woods Hole Oceanographic Institution for loan of North Atlantic right whale specimen Eg 1238; to Maureen Flannery and the Ornithology and Mammalogy Department of the California Academy of Sciences for scientific loan of blue whale specimen CAS MAM #23130; and to Russell Hart (Arbor Assays) for invaluable technical advice and consistent support of wildlife research employing unusual sample types. Bowhead whale baleen collected in Greenland was exported under CITES permit 16GL1167031, and imported under CITES permit 16CA01761/CWHQ; baleen from NARW Eg 1238 was imported from Canada under CITES permit 10US082589f9 and held under US National Oceanographic & Atmospheric Administration permit 18786; and blue whale baleen was collected within the USA under US National Oceanographic & Atmospheric Administration stranding authorizations to the California Academy of Sciences and related US Marine Mammal Stranding Network personnel. Baleen subsampling and laboratory analysis in 2016-18 occurred under a US National Oceanographic & Atmospheric Administration marine mammal parts authorization to K.E. Hunt. This study occurred with data-sharing approval from the North Atlantic Right Whale Consortium for the sightings records of Eg 1238; our thanks also to Philip Hamilton for detailed discussions regarding Eg 1238. This work was supported by (1) the Arizona Board of Regents Technology Research Initiative Fund; (2) the Center for Bioengineering Innovation at Northern Arizona University; (3) the Greenland Institute of Natural Resources; (4) the Woods Hole Oceanographic Institution Ocean Life Institute and (5) Fisheries and Ocean Canada's (DFO) Priorities and Partnership Strategic Initiatives Fund and Oceans Protection Plan.
Publisher Copyright:
© The Author(s) 2018. Published by Oxford University Press and the Society for Experimental Biology. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
PY - 2018/1/1
Y1 - 2018/1/1
N2 - Male baleen whales have long been suspected to have annual cycles in testosterone, but due to difficulty in collecting endocrine samples, little direct evidence exists to confirm this hypothesis. Potential influences of stress or adrenal stress hormones (cortisol, corticosterone) on male reproduction have also been difficult to study. Baleen has recently been shown to accumulate steroid hormones during growth, such that a single baleen plate contains a continuous, multi-year retrospective record of the whale's endocrine history. As a preliminary investigation into potential testosterone cyclicity in male whales and influences of stress, we determined patterns in immunoreactive testosterone, two glucocorticoids (cortisol and corticosterone), and stable-isotope (SI) ratios, across the full length of baleen plates from a bowhead whale (Balaena mysticetus), a North Atlantic right whale (Eubalaena glacialis) and a blue whale (Balaenoptera musculus), all adult males. Baleen was subsampled at 2 cm (bowhead, right) or 1 cm (blue) intervals and hormones were extracted from baleen powder with methanol, followed by quantification of all three hormones using enzyme immunoassays validated for baleen extract of these species. Baleen of all three males contained regularly spaced peaks in testosterone content, with number and spacing of testosterone peaks corresponding well to SI data and to species-specific estimates of annual baleen growth rate. Cortisol and corticosterone exhibited some peaks that co-occurred with testosterone peaks, while other glucocorticoid peaks occurred independent of testosterone peaks. The right whale had unusually high glucocorticoids during a period with a known entanglement in fishing gear and a possible disease episode; in the subsequent year, testosterone was unusually low. Further study of baleen testosterone patterns in male whales could help clarify conservation- and management-related questions such as age of sexual maturity, location and season of breeding, and the potential effect of anthropogenic and natural stressors on male testosterone cycles.
AB - Male baleen whales have long been suspected to have annual cycles in testosterone, but due to difficulty in collecting endocrine samples, little direct evidence exists to confirm this hypothesis. Potential influences of stress or adrenal stress hormones (cortisol, corticosterone) on male reproduction have also been difficult to study. Baleen has recently been shown to accumulate steroid hormones during growth, such that a single baleen plate contains a continuous, multi-year retrospective record of the whale's endocrine history. As a preliminary investigation into potential testosterone cyclicity in male whales and influences of stress, we determined patterns in immunoreactive testosterone, two glucocorticoids (cortisol and corticosterone), and stable-isotope (SI) ratios, across the full length of baleen plates from a bowhead whale (Balaena mysticetus), a North Atlantic right whale (Eubalaena glacialis) and a blue whale (Balaenoptera musculus), all adult males. Baleen was subsampled at 2 cm (bowhead, right) or 1 cm (blue) intervals and hormones were extracted from baleen powder with methanol, followed by quantification of all three hormones using enzyme immunoassays validated for baleen extract of these species. Baleen of all three males contained regularly spaced peaks in testosterone content, with number and spacing of testosterone peaks corresponding well to SI data and to species-specific estimates of annual baleen growth rate. Cortisol and corticosterone exhibited some peaks that co-occurred with testosterone peaks, while other glucocorticoid peaks occurred independent of testosterone peaks. The right whale had unusually high glucocorticoids during a period with a known entanglement in fishing gear and a possible disease episode; in the subsequent year, testosterone was unusually low. Further study of baleen testosterone patterns in male whales could help clarify conservation- and management-related questions such as age of sexual maturity, location and season of breeding, and the potential effect of anthropogenic and natural stressors on male testosterone cycles.
KW - Baleen
KW - Glucocorticoids
KW - Marine mammals
KW - Reproduction
KW - Stress
KW - Testosterone
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U2 - 10.1093/conphys/coy049
DO - 10.1093/conphys/coy049
M3 - Article
AN - SCOPUS:85063394821
SN - 2051-1434
VL - 6
JO - Conservation Physiology
JF - Conservation Physiology
IS - 1
ER -