Discrete-space continuous-time models of marine mammal exposure to Navy sonar
This study was supported by Office of Naval Research (ONR) grant N00014- 16-1-2858: "PCoD+: Developing widely-applicable models of the population consequences of disturbance". Funding support for tagging was provided by the U.S. Navy's ONR and Living Marine542 Resources (LMR) program, the Chief of Naval Operations' Energy and Environmental Readiness Division and the NOAA Fisheries Ocean Acoustics Program544 (see Joyce et al. (2020) for details). Hawai'i field efforts were funded by the U.S. Navy (Pacific Fleet, LMR) and the National Marine Fisheries Service (Pacific Islands Fisheries Science Center). Field efforts were supported by grants from the U.S. Navy's LMR and N45 programs. ; Assessing the patterns of wildlife attendance to specific areas is relevant across many fundamental and applied ecological studies, particularly when animals are at risk of being exposed to stressors within or outside the boundaries of those areas. Marine mammals are increasingly being exposed to human activities that may cause behavioral and physiological changes, including military exercises using active sonars. Assessment of the population-level consequences of anthropogenic disturbance requires robust and efficient tools to quantify the levels of aggregate exposure for individuals in a population over biologically relevant time frames. We propose a discrete-space, continuous-time approach to estimate individual transition rates across the boundaries of an area of interest, informed by telemetry data collected with uncertainty. The approach allows inferring the effect of stressors on transition rates, the progressive return to baseline movement patterns, and any difference among individuals. We apply the modeling framework to telemetry data from Blainville's beaked whale (Mesoplodon densirostris) tagged in the Bahamas at the Atlantic Undersea Test and Evaluation Center (AUTEC), an area used by the U.S. Navy for fleet readiness training. We show that transition rates changed as a result of exposure to sonar exercises in the area, ...