Assessing the post-release effects of capture, handling and placement of satellite telemetry devices on narwhal(Monodon monoceros)movement behaviour

Abstract

Animal-borne telemetry devices have become a popular and valuable means for studying the cryptic lives of cetaceans. Evaluating the effect of capture, handling and tagging procedures remains largely unassessed across species. Here, we examine the effect of capture, handling and tagging activities on an iconic Arctic cetacean, the narwhal (Monodon monoceros), which has previously been shown to exhibit an extreme response to extended capture and handling. Using accelerometry-derived metrics of behaviour, including activity level, energy expenditure and swimming activity, we quantify the post-release responses and time to recovery of 19 individuals following capture and tagging activities considering the intrinsic covariates of sex and individual size and the extrinsic covariates of handling time and presence of a ‘bolt-on’ satellite telemetry device. From accelerometer-derived behaviour, most narwhals appeared to return to mean baseline behaviour (recovery) within 24 hours after release, which was supported by longer-term measures of diving data. None of the covariates measured, however, had an effect on the time individuals took to recover following release. Using generalized additive models to describe changes in behaviour over time, we found handling time to be a significant predictor of activity levels, energy expenditure and swimming behaviour following release. Individuals held for the longest period (>40 min) were found to display the largest effect in behaviour immediately following release with respect to swimming behaviour and activity levels. We also found some support for relationships between activity levels, energy expenditure and swimming activity and two other covariates: sex and the attachment of a bolt-on configuration satellite tags. Our results indicate that narwhals recover relatively quickly following capture, handling and tagging procedures, but we suggest that researchers should minimize handling time and further investigation is needed on how to mitigate potential effects of bolt-on satellite tags in these sensitive species.

Integrating Biologging and Behavioral State Modeling to Identify Cryptic Behaviors and Post-capture Recovery Processes: New Insights From a Threatened Marine Apex Predator

“…Supporting this explanation, offshore dispersal of white sharks coincided with a period of faster tailbeats (i.e., rapid movement), which gradually slowed to a more constant average rate, indicating a population-level recovery period (return to "baseline" tailbeat signature) of 9.7 h. This pattern and rate of TBC recovery is similar to that identified for common blacktip sharks (Carcharhinus limbatus, 9 h; Whitney et al, 2016), but longer than for tiger sharks (Galeocerdo cuvier, 4 h; Andrzejaczek et al, 2019a), potentially suggesting lower sensitivity to capture in tiger sharks (consistent with Gallagher et al, 2014). Activity level metrics such as TBC are clearly useful for enabling standardized comparisons of recovery rates both between and within species (Brivio et al, 2015;Whitney et al, 2016;Shuert et al, 2021), yet such applications amongst elasmobranchs remain rare or are limited by short post-release monitoring periods (Bullock et al, 2015;Whitney et al, 2018;Raoult et al, 2019). Despite a low sample size, we also revealed that recovery times increased as shark length decreased.…”

“…So far, daily diary tags have been used to reveal many aspects of aquatic animals' natural behaviors including foraging activities, cost-efficient movement strategies, and habitat use (Shepard et al, 2011;Benoit-Bird et al, 2013;Andrzejaczek et al, 2019a). By contrast, applied behavioral research on disturbances following capture in marine and terrestrial systems has mostly relied on either traditional biotelemetry, pop-up time-depth archival tags, or accelerometers (Afonso and Hazin, 2014;Rode et al, 2014;Barnes et al, 2016;Becciolini et al, 2019;Bowlby et al, 2021;Shuert et al, 2021). However, biotelemetryderived movements or depth profiles are often insufficient for resolving cryptic behavioral processes (e.g., foraging and resting) relevant to recovery, especially in aquatic systems where telemetry data are particularly intermittent and coarse (Andrzejaczek et al, 2018(Andrzejaczek et al, , 2019a.…”

A sampling, exposure and receptor framework for identifying factors that modulate behavioural responses to disturbance in cetaceans

“…Assessing an individuals' 'ease of tagging', that is, the number of attempts or time taken to tag, TA B L E 1 Sampling-Exposure-Receptor framework (SERF). Further details for each category and factor are provided in SI S1, and a template is available in SI S2 Predation pressure-human Stankowich (2008) could facilitate investigation of how baseline/response metrics differ (Schuert et al, 2021). Similarly, it is important to quantify responses to tagging which, in marine mammals and other taxa, have modulated subsequent responses to stressors (Miller et al, 2009;Sun et al, 2015).…”

“…could facilitate investigation of how baseline/response metrics differ (Schuert et al, 2021). Similarly, it is important to quantify responses to tagging which, in marine mammals and other taxa, have modulated subsequent responses to stressors (Miller et al, 2009;Sun et al, 2015).…”

“…Ideally, BRS protocols should minimise potential ‘trappability’ biases, although this is challenging for wild marine mammal populations. Assessing an individuals' ‘ease of tagging’, that is, the number of attempts or time taken to tag, could facilitate investigation of how baseline/response metrics differ (Schuert et al, 2021 ). Similarly, it is important to quantify responses to tagging which, in marine mammals and other taxa, have modulated subsequent responses to stressors (Miller et al, 2009 ; Sun et al, 2015 ).…”