VARYING COEFFICIENTS CORRELATED VELOCITY MODELS IN COMPLEX LANDSCAPES WITH BOUNDARIES APPLIED TO NARWHAL RESPONSES TO NOISE EXPOSURE

• Main Authors: Delporte, Alexandre, Ditlevsen, Susanne, Samson, Adeline
• Other Authors: Université Grenoble Alpes (UGA), University of Copenhagen = Københavns Universitet (UCPH)
• Format: Report
• Language: English
• Published: HAL CCSD 2024
• Subjects: behavioral response study; stochastic differential equations; mixed effect model; [STAT]Statistics [stat]; Arctic; Greenland; Scoresby; narwhal*; Scoresby Sound
• Online Access: https://hal.science/hal-04684712; https://hal.science/hal-04684712/document; https://hal.science/hal-04684712/file/narwhals_AOAS.pdf

International audience Narwhals in the Arctic are increasingly exposed to human activities that can temporarily or permanently threaten their survival by modifying their behavior. We examine GPS data from a population of narwhals exposed to ship and seismic airgun noise during a controlled experiment in 2018 in the Scoresby Sound fjord system in Southeast Greenland. The fjord system has a complex shore line, restricting the behavioral response options for the narwhals to escape the threats. We propose a new continuous-time correlated velocity model with varying coefficients that includes spatial constraints on movement. To assess the sound exposure effect we compare a baseline model for the movement before exposure to a response model for the movement during exposure. Our model, applied to the narwhal data, suggests increased tortuosity of the trajectories as a consequence of the spatial constraints, and further indicates that sound exposure can disturb narwhal motion up to a couple of tens of kilometers. Specifically, we found an increase in velocity and a decrease in the movement persistence.