Monitoring Stress Levels and Calving Intervals using Baleen

Co-Principal Investigators: Raphaela Stimmelmayr and Craig George (NSB-DWM) and Kathleen Hunt and Rosalind Rolland (John H. Prescott Marine Laboratory, New England Aquarium, Boston, MA)
Collaborators: AEWC, New England Aquarium
Funding: NSB-DWM, NSB/Shell Baseline Studies Program

Summary: For many years, local communities have been concerned about potential impacts to bowhead whales from oil and gas activity, climate change, and other stressors. We know that bowheads move away from sounds made by humans, including seismic surveys, ships, and drilling sounds. In addition to deflection, based on other studies, the whales’ stress levels likely increase as well. To better understand the changes in stress levels of bowheads, we are measuring levels of the stress hormone cortisol in different tissues including urine, blood, feces and blubber, which represent what the whale has experienced in the past few hours, days, or maybe longer. Because baleen can represent 15 to 20 years in a whale’s life, we have started a project, working with the New England Aquarium,  to see if we can measure cortisol in baleen.

Preliminary findings confirm that baleen contains measurable levels of the stress hormone cortisol and also progesterone, a female pregnancy hormone. We are also interested in looking at progesterone for two reasons. One, when a female is pregnant, her stress hormone levels are also high. We want to be sure we take into account any possible pregnancies when we evaluate how stress levels in bowheads may have changed over time. Two, we should be able to tell how frequently a female has a calf. Both of these questions are important for monitoring the health of bowheads.

drilling core samples of baleen
Taking core samples from baleen plates

Preliminary Findings: The stress hormone cortisol and the reproductive hormone progesterone were detected in baleen from all 16 bowhead whales sampled. In gumline samples from the base of the baleen plate, females had significantly higher concentrations of cortisol and progesterone as compared with males. Progesterone concentrations were extremely higher in pregnant females than in males and non-pregnant females.

This new approach could be a novel way to compare stress levels measured in bowhead baleen from the past (i.e. commercial whaling) with today and into the future. We are hopeful we can assess stress impacts from climate change and increasing human activity in the Arctic. This information was presented to the AEWC at the 2014 mini-convention and a short paper outlining these preliminary results has been published (see citation below). We are preparing a new proposal to obtain future funding to continue this promising research.

Report:

Hunt, Kathleen E., Raphaela Stimmelmayr, Craig George, Cyd Hanns, Robert Suydam, Harry Brower, Jr, Rolalind M. Rolland. 2014. Baleen hormones: a novel tool for retrospective assessment of stress and reproduction in bowhead whales (Balaena mysticetus). Conservation Physiology 2: doi:10.1093/conphys/cou030.