Meeting Abstract

P2-14   -   Multi-year progesterone profiles during pregnancy in baleen of humpback whales (Megaptera novaeangliae) Lowe, CL*; Hunt, KE; Robbins, J; Seton, RE; Rogers, M; Gabriele, CM; Neilson, JL; Landry, S; Teerlink, SS; Buck, CL; Carley L. Lowe*, Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ ; Department of Biology, George Mason University & Smithsonian-Mason School of Conservation, Front Royal, VI ; Center for Coastal Studies, Provincetown, MA ; College of the Atlantic, Bar Harbor, ME; Alaska Fisheries Science Center Auke Bay Laboratories, NOAA, National Marine Fisheries Service, Juneau, AK ; Humpback Whale Monitoring Program, Glacier Bay National Park & Preserve, Gustavus, AK ; Humpback Whale Monitoring Program, Glacier Bay National Park & Preserve, Gustavus, AK ; Center for Coastal Studies, Provincetown, MA ; Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ ; Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ; NOAA Fisheries, Alaska Regional Office, Protected Resources Division, Juneau AK carley.lowe@gmail.com

Baleen whales are subject to myriad natural and anthropogenic stressors but understanding how these stressors affect physiology is difficult. Measurement of adrenal glucocorticoid hormones involved in the vertebrate stress response (cortisol and corticosterone) in baleen could help fill this data gap. Baleen analysis is a powerful tool, allowing for a retrospective re-creation of multiple years of glucocorticoid hormone concentrations at approximately a monthly resolution. We hypothesized that whales that died from acute causes (e.g., ship strike) would have lower levels of baleen glucocorticoids than whales that died from extended illness or injury (e.g., long-term entanglement in fishing gear). To test this hypothesis, we extracted hormones from baleen plates of four humpback whales (Megaptera novaeangliae) with well-documented deaths including multiple and chronic entanglements (n=1, female), ship strike (n=2, male and female), and chronic illness with nutritional stress (n=1, male). Over approximately three years of baleen growth and during multiple entanglements, the entangled whale had average corticosterone levels 80 – 187% higher than the other three whales but cortisol levels were similar to two of the other three whales. The nutritionally stressed and chronically ill whale showed a slow increase in both cortisol and corticosterone spanning approximately three years, followed by a sharp decline in both hormones before death, possibly indicative of adrenal failure in this moribund individual. This whale’s correlation between cortisol and corticosterone was significant but there were no correlations in the other three whales. Our results show that cortisol and corticosterone concentrations vary according to the type and duration of illness or injury. Single point glucocorticoid concentrations should be interpreted with caution as low values can occur in whales experiencing pronounced stress and individual baselines can be highly variable. Baleen analysis is a promising tissue type for retrospective analyses of physiological responses to various stressors affecting baleen whales.