Dear MARMAM-ers,

My co-authors and I are pleased to announce the publication of the below paper in Frontiers in Marine Science.

Bouchet PJ, Harris CM, Thomas L. (2021) Assessing the role of sampling uncertainty when predicting behavioral responses of tagged cetaceans exposed to naval sonar. Frontiers in Marine Science, 8: 674554. doi: 10.3389/fmars.2021.674554

In this work, we conducted simulations to determine how the quality of data derived from different tagging technologies (DTAGs vs Argos satellite tags) affected predictions of behavioural responses in Cuvier’s beaked whales exposed to low- and mid-frequency active sonar.

We demonstrate that (1) the zone of impact from a sonar source is under-estimated in most test conditions, (2) substantial reductions in the uncertainty surrounding dose-response relationships are possible at higher sample sizes, and (3) this largely holds true irrespective of tag choice under the scenarios considered, unless positional fixes from satellite tags are consistently poor.

The paper is freely accessible at: https://www.frontiersin.org/articles/10.3389/fmars.2021.674554/full

Abstract:

Concerns over cetacean mortality events coincident with maritime warfare exercises have motivated efforts to characterize the effects of anthropogenic noise on free-ranging whales and dolphins. By monitoring the movement, diving, and acoustic behaviors of individual whales before, during, and after sound exposure, behavioral response studies (BRSs) have supported significant progress in our understanding of the sensitivity of various cetacean species to high-powered naval sonar signals. However, differences in the designs and sampling capabilities of animal-borne tags typically used in BRS experiments prompt questions about the influence of data resolution in quantitative assessments of noise impacts. We conducted simulations to examine how uncertainty in the acoustic dose either measured on high-resolution multi-sensor biologging tags or modeled from position-transmitting satellite telemetry tags may affect predictions of behavioral responses in Cuvier’s beaked whales (Ziphius cavirostris) exposed to low- and mid-frequency active sonar. We considered an array of scenarios representative of real-world BRSs and used posterior estimates of dose-response functions obtained under an established Bayesian hierarchical modeling framework to explore the consequences of different tag choices for management decision-making. Our results indicate that (1) the zone of impact from a sonar source is under-estimated in most test conditions, (2) substantial reductions in the uncertainty surrounding dose-response relationships are possible at higher sample sizes, and (3) this largely holds true irrespective of tag choice under the scenarios considered, unless positional fixes from satellite tags are consistently poor. Strategic monitoring approaches that combine both archival biologging and satellite biotelemetry are essential for characterizing complex patterns of behavioral change in cetaceans exposed to increasing levels of acoustic disturbance. We suggest ways in which BRS protocols can be optimized to curtail the effects of uncertainty.

Best wishes,

Phil

Dr. Phil Bouchet | Research Fellow

Centre for Research into Ecological & Environmental Modelling (CREEM)

The Observatory, Buchanan Gardens
University of St Andrews, St Andrews Fife
KY16 9LZ, Scotland (UK)