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Schultz, I.R.; Bolton, J.L.; Stimmelmayr, R.; Ylitalo, G.M.

doi:10.1016/b978-0-12-818969-6.00037-6

Cited by 2 publications

(2 citation statements)

References 52 publications

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“…An additional possibility is accumulation of endocrine-disrupting toxicants over time; though bowheads are generally assumed to be less vulnerable to such effects than other cetaceans due to their relatively low trophic level (i.e., feeding primarily on zooplankton), their very long lifespan may eventually allow such pollutants to reach tissue concentrations that have physiological impacts ( Hoekstra et al. 2002 ; Schultz et al. 2021 ).…”

Section: Discussionmentioning

confidence: 99%

Male Bowhead Whale Reproductive Histories Inferred from Baleen Testosterone and Stable Isotopes

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Ferguson

et al. 2022

Integrative Organismal Biology

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Synopsis Male mammals of seasonally reproducing species typically have annual testosterone (T) cycles, with T usually peaking during the breeding season, but occurrence of such cycles in male mysticete whales has been difficult to confirm. Baleen, a keratinized filter-feeding apparatus of mysticetes, incorporates hormones as it grows, such that a single baleen plate can record years of endocrine history with sufficient temporal resolution to discern seasonal patterns. We analyzed patterns of T every 2 cm across the full length of baleen plates from nine male bowhead whales (Balaena mysticetus) to investigate occurrence and regularity of T cycles and potential inferences about timing of breeding season, sexual maturation, and reproductive senescence. Baleen specimens ranged from 181–330 cm in length, representing an estimated 11 years (smallest whale) to 22 years (largest whale) of continuous baleen growth, as indicated by annual cycles in stable isotopes. All baleen specimens contained regularly spaced areas of high T content (T peaks) confirmed by time series analysis to be cyclic, with periods matching annual stable isotope cycles of the same individuals. In 8 of the 9 whales, T peaks preceded putative summer isotope peaks by a mean of 2.8 months, suggesting a mating season in late winter / early spring. The only exception to this pattern was the smallest and youngest male, which had T peaks synchronous with isotope peaks. This smallest, youngest whale also did not have T peaks in the first half of the plate, suggesting initiation of T cycling during the period of baleen growth. Linear mixed effect models suggest that whale age influences T concentrations, with the two largest and oldest males exhibiting a dramatic decline in T peak concentration across the period of baleen growth. Overall, these patterns are consistent with onset of sexual maturity in younger males and possible reproductive senescence in older males. We conclude that adult male bowheads undergo annual T cycles, and that analyses of T in baleen may enable investigation of reproductive seasonality, timing of the breeding season, and life history of male whales.

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Section: Discussionmentioning

confidence: 99%

Male Bowhead Whale Reproductive Histories Inferred from Baleen Testosterone and Stable Isotopes

Hunt

Buck

Ferguson

et al. 2022

Integrative Organismal Biology

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“…Further, there is a need to better understand the interactions of mercury and selenium on cetacean health and potential sources of high mercury exposure. Schultz et al (2021) provided an integrative review of long-term monitoring data on persistent organic pollutants (POPs) in BCB bowhead whales and presented new data on polycyclic aromatic hydrocarbon (PAH) exposure and heavy metal trends in various tissues from whales harvested for subsistence by Alaskan Inuit during 2006-2015. Tissues collected from 2006-2007 had elevated median ∑PAH values compared to whales sampled in subsequent years.…”

Section: Attention: Cg Scmentioning

confidence: 99%

Report of the Scientific Committee

2022

JCRM

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Contaminants

Cited by 2 publications

References 52 publications

Male Bowhead Whale Reproductive Histories Inferred from Baleen Testosterone and Stable Isotopes

Male Bowhead Whale Reproductive Histories Inferred from Baleen Testosterone and Stable Isotopes

Report of the Scientific Committee

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