Meeting Abstract
Fecal hormone analysis shows potential for noninvasive assessment of population-level patterns in stress and reproduction in large whales. However, data are lacking on collection methodology and assay validations for most species, particularly those mysticetes that have variable diets and highly liquid feces. We tested fecal-collection techniques for humpback whales (Megaptera novaeangliae), followed by assay validations for five hormone classes (progestins, estrogens, androgens, glucocorticoids, thyroid hormones) and comparisons to known sex and reproductive state where possible. 55 humpback fecal samples were collected at sea during 2012-2013, of which 48 were large enough to assay for multiple hormones and 43 were from known whales. All five hormone assays were successfully validated with parallelism and accuracy tests. Calf samples had much higher fecal hormone content than samples from other whales, potentially due to ingestion of maternal steroids via milk fat. Females resighted with a calf the next year (e.g. definitely pregnant) had significantly higher fecal progestins (P=0.0021, t-test) than females resighted but with no calf (e.g. probably nonpregnant). One potential case of calf loss was noted. Males had significantly higher fecal androgens than nonpregnant females (P=0.0396, t-test). The only sample from an entangled whale had fecal glucocorticoids more than two standard deviations above the population mean. Fecal estrogens and fecal thyroid hormones showed no obvious trends, though sample size was low. Despite the challenges of sample collection and despite low sample mass, fecal sampling appears viable for humpback whales and produces biologically relevant data that could be useful for assessment of pregnancy, calf loss, other reproductive parameters, and stress physiology.
