Prolonged baleen hormone cycles suggest atypical reproductive endocrinology of female bowhead whales.

Serial measurements of hormone concentrations along baleen plates allow for reconstructions of mysticete whale reproductive histories. We assessed gestation and calving interval in bowhead whales () by measuring progesterone, oestradiol, corticosterone and nitrogen stable isotope ratios (δN) along baleen of 10 females from the eastern Canada-west Greenland population. Three immature females (body size < 14.

Multi-year patterns in testosterone, cortisol and corticosterone in baleen from adult males of three whale species.

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.

Multiple steroid and thyroid hormones detected in baleen from eight whale species.

Recent studies have demonstrated that some hormones are present in baleen powder from bowhead ( and North Atlantic right () whales. To test the potential generalizability of this technique for studies of stress and reproduction in large whales, we sought to determine whether all major classes of steroid and thyroid hormones are detectable in baleen, and whether these hormones are detectable in other mysticetes. Powdered baleen samples were recovered from single specimens of North Atlantic right, bowhead, blue ( [.

Multi-year longitudinal profiles of cortisol and corticosterone recovered from baleen of North Atlantic right whales (Eubalaena glacialis).

Research into stress physiology of mysticete whales has been hampered by difficulty in obtaining repeated physiological samples from individuals over time. We investigated whether multi-year longitudinal records of glucocorticoids can be reconstructed from serial sampling along full-length baleen plates (representing ∼10years of baleen growth), using baleen recovered from two female North Atlantic right whales (Eubalaena glacialis) of known reproductive history. Cortisol and corticosterone were quantified with immunoassay of subsamples taken every 4cm (representing ∼60d time intervals) along a full-length baleen plate from each female.

Persistent Organic Pollutant and Hormone Levels in Harbor Porpoise with B Cell Lymphoma.

B-cell lymphoma, a common morphologic variant of non-Hodgkin lymphoma, has been associated with persistent pollutants in humans, but this association is not well-characterized in top-level predators sharing marine resources with humans. We characterized and compared blubber contaminants and hormones of a pregnant harbor porpoise (Phocoena phocoena) with B-cell lymphoma, with those in two presumed healthy fishery by-caught porpoises with no lymphoma: a pregnant adult and female juvenile. Common historic use compounds, including polychlorinated biphenyls, polybrominated diphenyl ethers, and pesticides, were evaluated in blubber samples from three porpoises.