We analyze trade-offs in the longevity, resolution, and continuity of data records from non-recoverable satellite-linked tags on deep-diving Ziphius cavirostris in the context of a behavioral response study of acute noise exposure.

To identify possible behavioral responses in dive data collected from satellite-linked time–depth recorders, and to inform the selection and parameters for subsequent individual and population-level response analyses, we propose to use kernel density estimates of conditional distributions for quantitative comparison of pre- and post-exposure behavior.

Argos satellite telemetry is used globally to track terrestrial and aquatic megafauna, yet the accuracy of this system has been described empirically only for a limited number of species. We used Argos-linked archival tags with Fastloc GPS deployed on free-ranging sperm (Physeter macrocephalus), blue (Balaenoptera musculus), and fin (B. physalus) whales to derive empirical estimates of Argos location errors for these species, examine possible behavior-related differences, and test the effect of incorporating species-specific error parameters on performance of a commonly used movement model.

Despite spending most time underwater, the technology in use to track whales over large geographic ranges via satellite has been largely limited to locational data, with most applications focusing on characterizing their horizontal movements. We describe the development of the RDW tag, a new Argos-based satellite telemetry device that incorporates sensors for monitoring the movements and dive behavior of large whales over several months without requiring recovery. Based on an implantable design, the tag features a saltwater conductivity switch, a tri-axial accelerometer, and an optional pressure transducer, along with onboard software for data processing and detection of behavioral events or activities of interest for transmission.

We conducted a comparative analysis of movement strategies in blue (Balaenoptera musculus) and fin (B. physalus) whales across the eastern North Pacific (ENP). We assessed patterns of dispersal, revisitation, and residency within the California Current Ecosystem (CCE), a key seasonal feeding habitat, while considering biases in telemetry data such as device longevity, site fidelity, and sample representativeness. The dataset comprised 271 tracks from 176 blue and 95 fin whales tagged between 1994 and 2018 with two types of implantable tags. Tagging locations were grouped into southern California (SCA) and central-northern California (CCA–NCA) for blue whales, and SCA and central California-Pacific Northwest (CCA–PNW) for fin whales.

Studies of deep-diving beaked whales using Argos satellite-linked location-depth tags frequently return data with large gaps in the diving record. We document the steps taken to eliminate these data gaps and collect weeks of continuous time series data for a behavioral response study that took place in 2017.

Common minke whales (Balaenoptera acutorostrata; hereafter, “minke whales”) are globally distributed, but can exhibit cryptic behavior and sometimes occur in small groups, and are thus challenging to study. Like other baleen whales, this species makes seasonal migrations. However, aspects of their movement and behavioral patterns are not well understood. The Mid-Atlantic Bight (MAB), situated along the eastern coast of the United States, is a known migratory route for minke whales, but earlier observations suggest this area may also serve as foraging grounds despite various natural and anthropogenic stressors. We deployed three satellite tags on minke whales, including two in the New York Bight (NYB) in September 2023 and one off of Virginia (VA) in February 2024, to characterize movement patterns in and around the MAB. These tags yield the first record of minke whale movements in this area and the first dive record for minke whales in the broader northwest Atlantic. The animals showed two types of movement, area restricted search (ARS) and transit, likely reflecting foraging and migratory behavior, respectively. In the NYB, we found evidence of ARS in mid-shelf waters, including in offshore wind lease areas. In VA coastal waters, ARS was documented in and around shipping lanes. We also found evidence of southward migration in autumn, with one animal exhibiting a shift from ARS to sustained transitory movements in late October. In the NYB, the whales exhibited strong diel trends in diving behavior, but this was not observed for the individual off VA. These data provide initial quantification of minke whale behavior and habitat use in the MAB, including in areas that overlap with anthropogenic activities, providing insight for further research, management and conservation.