Assessing Beaked Whale Reproduction and Stress Response Relative to Sonar Activity at the Atlantic Undersea Test and Evaluation Center (AUTEC)
NOAA Southwest Fisheries Science Center La Jolla United States
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Atypical mass strandings and behavioral responses of beaked whales have been correlated with exposure to naval sonar, highlighting a need to understand the potential physiological impacts to individual whales and if these in turn represent a biologically significant threat to exposed populations. The long-term goal of this study is to assess glucocorticoid levels from blubber biopsies of targeted species, to assess stress levels relative to sonar exposure. Specifically, the project aims to collect biopsy samples at the U.S. Navys Atlantic Undersea Test and Evaluation Center AUTEC in the Andros-AUTEC Operating Area where fleet readiness training involves regular use of mid-frequency active sonars, and compare the levels to those measured in biopsies collected from control populations within the Bahamas region that are less exposed to sonar activity. In parallel, pregnancy states will be ascertained via blubber progesterone levels in both groups of animals to investigate whether there is a relationship between sonar activity, stress measures, and reproductive rates, to assess population-level impacts. The primary objectives of the study are 1 To assess stress levels measured from glucocorticoid concentrations in blubber biopsies relative to sonar activity, and relate these to pregnancy rates from progesterone concentrations in the same tissue for Blainvilles beaked whales Mesoplodon densirostris and sperm whales Physeter macrocephalus. 2 To collect photo-identification data to monitor repeated sampling of individuals, construct sighting histories and identify consistent associates as covariates for stress analyses and to document successful calving events for comparison to hormone-derived pregnancy rates. The experimental design of this study is based on a population comparison to compare beaked whale and sperm whale stress levels and pregnancy rates between areas with contrasting sonar activity.
- Biological Oceanography