Meeting Abstract
Recent studies have demonstrated that progesterone and cortisol are detectable in baleen from two closely related species of mysticete whale, North Atlantic right whale (Eubalaena glacialis, NARW), and bowhead whale (Balaena mysticetus). Longitudinal profiles of both hormones in baleen appear to match known reproductive history across the period of baleen growth. We wished to determine whether other hormones are also detectable in baleen, and whether baleen hormones are detectable in other species. Powdered baleen samples were recovered from single baleen plates from stranded specimens of NARW, bowhead, sei (Balaenoptera [B.] borealis), fin (B. physalus), blue (B. musculus), minke (B. acutorostrata), and humpback (Megaptera novaeangliae) whales. For all species we tested hormone detectability, parallelism and (where sample volume permitted) accuracy, using commercial enzyme immunoassays for progesterone, cortisol, corticosterone, 17β-estradiol, testosterone, aldosterone, thyroxine and tri-iodothyronine. All hormones were detectable in baleen powder of all species and validation results were consistently good. Though data are limited to single samples from each species, these findings indicate that baleen hormone analyses may be applicable to a broad range of mysticetes. The variety of hormones detected suggests that baleen hormone analysis might be a suitable technique with which to explore questions that are often difficult to address in large whales, potentially including: pregnancy and inter-calving interval, estrous cycling in females, testosterone cycles in males, sexual maturation in both sexes, seasonal reproductive cycles, adrenal physiology, and metabolic rate.
