Context-dependent variability in the predicted daily energetic costs of disturbance for blue whales
MetadataShow full item record
Assessing the long-term consequences of sub-lethal anthropogenic disturbance on wildlife populations requires integrating data on fine-scale individual behavior and physiology into spatially and temporally broader, population-level inference. A typical behavioral response to disturbance is the cessation of foraging, which can be translated into a common metric of energetic cost. However, this necessitates detailed empirical information on baseline movements, activity budgets, feeding rates and energy intake, as well as the probability of an individual responding to the disturbance-inducing stressor within different exposure contexts. Here, we integrated data from blue whales (Balaenoptera musculus) experimentally exposed to military active sonar signals with fine-scale measurements of baseline behavior over multiple days or weeks obtained from accelerometry loggers, telemetry tracking and prey sampling. Specifically, we developed daily simulations of movement, feeding behavior and exposure to localized sonar events of increasing duration and intensity and predicted the effects of this disturbance source on the daily energy intake of an individual. Activity budgets and movements were highly variable in space and time and among individuals, resulting in large variability in predicted energetic intake and costs. In half of our simulations, an individual’s energy intake was unaffected by the simulated source. However, some individuals lost their entire daily energy intake under brief or weak exposure scenarios. Given this large variation, population-level models will have to assess the consequences of the entire distribution of energetic costs, rather than only consider single summary statistics. The shape of the exposure-response functions also strongly influenced predictions, reinforcing the need for contextually explicit experiments and improved mechanistic understanding of the processes driving behavioral and physiological responses to disturbance. This study presents a robust approach for integrating different types of empirical information to assess the effects of disturbance at spatio-temporal and ecological scales that are relevant to management and conservation.
Pirotta , E , Booth , C G , Cade , D E , Calambokidis , J , Costa , D P , Fahlbusch , J A , Friedlaender , A S , Goldbogen , J A , Harwood , J , Hazen , E L , New , L & Southall , B L 2021 , ' Context-dependent variability in the predicted daily energetic costs of disturbance for blue whales ' , Conservation Physiology , vol. 9 , no. 1 , coaa137 . https://doi.org/10.1093/conphys/coaa137
Copyright © The Author(s) 2021. Published by Oxford University Press and the Society for Experimental Biology. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
DescriptionFunding: This study was supported by the Office of Naval Research (ONR) [grant number N00014–19-1-2464: “BRS4PCoD:Integrating the results of Behavioral Response Studies intomodels of the Population Consequences of Disturbance”]. J.A.G., D.E.C. and J.A.F. were supported by the National Science Foundation (Division of Integrative Organismal Systems) [grant number 1656691], ONR Young Investigator Program [grant number N000141612477], ONR Defense University Research Instrumentation Program [grant number N000141612546] and Stanford University’s Terman and Bass Fellowships. The SOCAL-BRS project was supported by the US Navy’s Chief of Naval Operations Environmental Readiness Division, the US Navy’s Living Marine Resources Program and the Marine Mammal Program of the Office of Naval Research.
Items in the St Andrews Research Repository are protected by copyright, with all rights reserved, unless otherwise indicated.