Testosterone trends within and across seasons in male humpback whales (Megaptera novaeangliae) from Hawaii and Alaska
Advanced Search
Select up to three search categories and corresponding keywords using the fields to the right. Refer to the Help section for more detailed instructions.

Search our Collections & Repository

For very narrow results

When looking for a specific result

Best used for discovery & interchangable words

Recommended to be used in conjunction with other fields



Document Data
Clear All
Clear All

For additional assistance using the Custom Query please check out our Help Page


Testosterone trends within and across seasons in male humpback whales (Megaptera novaeangliae) from Hawaii and Alaska

Filetype[PDF-616.05 KB]


  • Journal Title:
    General and Comparative Endocrinology
  • Personal Author:
  • NOAA Program & Office:
  • Description:
    Understanding reproductive profiles and timing of reproductive events is essential in the management and conservation of humpback whales (Megaptera novaeangliae). Yet compared to other parameters and life history traits, such as abundance, migratory trends, reproductive rates, behavior and communication, relatively little is known about variations in reproductive physiology, especially in males. Here, an enzyme immunoassay (EIA) for testosterone was validated for use in biopsy samples from male humpback whales. Analyses were conducted on 277 North Pacific male humpback whale blubber samples, including 268 non-calves and 9 calves that were collected in the Hawaiian breeding grounds and the Southeast Alaskan feeding grounds from 2004 to 2006. Testosterone concentrations (ng/g) were significantly different between non-calves sampled in Hawaii (n = 182) and Alaska (n = 86, p < 0.05) with peak testosterone concentrations occurring in the winter (January–March) and the lowest concentrations occurring in the summer (June–September). Fall and spring showed increasing and decreasing trends in testosterone concentrations, respectively. Blubber testosterone concentrations in non-calves and calves sampled in Alaska were not significantly different. Blubber and skin from the same individual biopsies (n = 37) were also compared, with blubber having significantly higher testosterone concentrations (p < 0.05) than skin samples. We found variability in testosterone concentration with age, suggesting that male humpbacks reach peak lifetime testosterone concentrations in the breeding grounds around age 8–25 years. The testosterone profile of male humpback whales follows a predictable pattern for capital breeders, where testosterone begins to increase prior to the breeding season, stimulating the onset of spermatogenesis. Incorporation of reproductive hormonal profiles into our overall understanding of humpback whale physiology will shed additional light on the timing of reproduction and overall health of the recently delisted Hawaii distinct population segment (DPS).
  • Keywords:
  • Source:
    General and Comparative Endocrinology, 279, 164-173
  • DOI:
  • ISSN:
  • Format:
  • Publisher:
  • Document Type:
  • Rights Information:
    Accepted Manuscript
  • Compliance:
  • Main Document Checksum:
  • Download URL:
  • File Type:

Supporting Files

  • No Additional Files
More +

You May Also Like

Checkout today's featured content at repository.library.noaa.gov

Version 3.26.1