Use of hormones in assessing reproductive physiology of humpback whales (Megaptera novaeangliae) from Juneau, Alaska
Humpback whales (Megaptera novaeangliae) in Southeast Alaska have been studied for over 50 years, and are largely considered a recovery success since the cessation of commercial whaling. Reproductive physiology is an important factor to consider in studying population health and can provide importan...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2023-01-01
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| Series: | Theriogenology Wild |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2773093X2300034X |
| _version_ | 1797615883023024128 |
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| author | S. Atkinson V. Melica S. Teerlink K. Mashburn J. Moran H. Pearson |
| author_facet | S. Atkinson V. Melica S. Teerlink K. Mashburn J. Moran H. Pearson |
| author_sort | S. Atkinson |
| collection | DOAJ |
| description | Humpback whales (Megaptera novaeangliae) in Southeast Alaska have been studied for over 50 years, and are largely considered a recovery success since the cessation of commercial whaling. Reproductive physiology is an important factor to consider in studying population health and can provide important insights into the drivers contributing to population abundance fluctuations. Validated assays for progesterone and testosterone were used on blubber biopsies from humpback whales (N = 33 whales, 71 samples) near Juneau, Alaska, in 2020 and 2021. Long-term sighting histories were used to confirm detected pregnancies with calf sightings the following year. Blubber samples were divided into two seasonal bins (early and late summer). Pregnant females sampled in both early and late summer of both 2020 and 2021 showed elevated progesterone concentrations compared to other reproductive states (p < 0.05). Progesterone concentrations in adult male whales (0.3 ± 0.2 ng/g) were not significantly different from lactating or resting female whales. Blubber testosterone concentrations in adult male humpback whales ranged from 0.05 to 1.1 ng/g, and mean concentrations were approximately double those of female whales in any reproductive state. Pregnancy was detected in 5 of 11 and 4 of 9 adult females in 2020 and 2021 respectively, yielding summer season pregnancy rates for sexually mature females at 0.45, and 0.44, respectively. Calving rates were 0.36 and 0.22 in 2020 and 2021, respectively, and the annual growth rate for this subpopulation was calculated at 2.6 % per annum. One female had successful pregnancies for four consecutive years. These results demonstrate the synergistic value of combining immunoreactive assays and long-term sighting histories to further knowledge of reproductive physiology in individual humpback whales, which can be expanded to assessing the health of a population or ecosystem. |
| first_indexed | 2024-03-11T07:33:17Z |
| format | Article |
| id | doaj.art-c1016e7afefb44058dc7f51557f63eee |
| institution | Directory Open Access Journal |
| issn | 2773-093X |
| language | English |
| last_indexed | 2024-03-11T07:33:17Z |
| publishDate | 2023-01-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Theriogenology Wild |
| spelling | doaj.art-c1016e7afefb44058dc7f51557f63eee2023-11-17T05:28:46ZengElsevierTheriogenology Wild2773-093X2023-01-013100050Use of hormones in assessing reproductive physiology of humpback whales (Megaptera novaeangliae) from Juneau, AlaskaS. Atkinson0V. Melica1S. Teerlink2K. Mashburn3J. Moran4H. Pearson5University of Alaska Fairbanks, College of Fisheries and Ocean Sciences, 17101 Point Lena Loop Road, Juneau, AK 99801, USA; Corresponding author.University of Alaska Fairbanks, College of Fisheries and Ocean Sciences, 17101 Point Lena Loop Road, Juneau, AK 99801, USANational Marine Fisheries Service, Alaska Regional Office, 709 West 9th Street, Juneau, AK 99801, USAUniversity of Alaska Fairbanks, College of Fisheries and Ocean Sciences, 17101 Point Lena Loop Road, Juneau, AK 99801, USAAlaska Fisheries Science Center, National Oceanic and Atmospheric Administration, Juneau, 17109 Pt. Lena Loop Road, Juneau, AK 99801, USAUniversity of Alaska Southeast, Department of Natural Sciences, 11066 Auke Lake Way, Juneau, AK 99801, USAHumpback whales (Megaptera novaeangliae) in Southeast Alaska have been studied for over 50 years, and are largely considered a recovery success since the cessation of commercial whaling. Reproductive physiology is an important factor to consider in studying population health and can provide important insights into the drivers contributing to population abundance fluctuations. Validated assays for progesterone and testosterone were used on blubber biopsies from humpback whales (N = 33 whales, 71 samples) near Juneau, Alaska, in 2020 and 2021. Long-term sighting histories were used to confirm detected pregnancies with calf sightings the following year. Blubber samples were divided into two seasonal bins (early and late summer). Pregnant females sampled in both early and late summer of both 2020 and 2021 showed elevated progesterone concentrations compared to other reproductive states (p < 0.05). Progesterone concentrations in adult male whales (0.3 ± 0.2 ng/g) were not significantly different from lactating or resting female whales. Blubber testosterone concentrations in adult male humpback whales ranged from 0.05 to 1.1 ng/g, and mean concentrations were approximately double those of female whales in any reproductive state. Pregnancy was detected in 5 of 11 and 4 of 9 adult females in 2020 and 2021 respectively, yielding summer season pregnancy rates for sexually mature females at 0.45, and 0.44, respectively. Calving rates were 0.36 and 0.22 in 2020 and 2021, respectively, and the annual growth rate for this subpopulation was calculated at 2.6 % per annum. One female had successful pregnancies for four consecutive years. These results demonstrate the synergistic value of combining immunoreactive assays and long-term sighting histories to further knowledge of reproductive physiology in individual humpback whales, which can be expanded to assessing the health of a population or ecosystem.http://www.sciencedirect.com/science/article/pii/S2773093X2300034XHumpback whaleMegaptera novaeangliaeProgesteroneTestosteronePregnancy rateCalving rate |
| spellingShingle | S. Atkinson V. Melica S. Teerlink K. Mashburn J. Moran H. Pearson Use of hormones in assessing reproductive physiology of humpback whales (Megaptera novaeangliae) from Juneau, Alaska Theriogenology Wild Humpback whale Megaptera novaeangliae Progesterone Testosterone Pregnancy rate Calving rate |
| title | Use of hormones in assessing reproductive physiology of humpback whales (Megaptera novaeangliae) from Juneau, Alaska |
| title_full | Use of hormones in assessing reproductive physiology of humpback whales (Megaptera novaeangliae) from Juneau, Alaska |
| title_fullStr | Use of hormones in assessing reproductive physiology of humpback whales (Megaptera novaeangliae) from Juneau, Alaska |
| title_full_unstemmed | Use of hormones in assessing reproductive physiology of humpback whales (Megaptera novaeangliae) from Juneau, Alaska |
| title_short | Use of hormones in assessing reproductive physiology of humpback whales (Megaptera novaeangliae) from Juneau, Alaska |
| title_sort | use of hormones in assessing reproductive physiology of humpback whales megaptera novaeangliae from juneau alaska |
| topic | Humpback whale Megaptera novaeangliae Progesterone Testosterone Pregnancy rate Calving rate |
| url | http://www.sciencedirect.com/science/article/pii/S2773093X2300034X |
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