Biology subjects

Tackaberry, J. E.

Publications and source records attributed to Tackaberry, J. E..

3 recordsLinked to original sources

bioRxiv2024

Effects of satellite-linked telemetry tags on humpback whales in the Gulf of Maine: photographic assessment of tag sites

Hundreds of large whales have been tracked using consolidated (Type-C) satellite tags, yet there have been few studies on their impacts on whale health. In 2011, we initiated the first study designed to evaluate the effects of these tags in a baleen whale. Between 2011 and 2018, we tagged 79 North Atlantic humpback whales in the Gulf of Maine. We initially deployed commonly-used tags with an articulation between the anchor and transmitter (n=35, 2011-2012). However, evidence of breakage prompted the development and use of more robust, integrated tags (n=45). Tagged individuals were photographed immediately prior to, during and up to 11 years after tagging. They were re-encountered on an average of 41.3 days (SD=44.3), yielding 2,971 photographed sightings through 2022. An objective scoring system was developed to characterise tag site tissue responses based on photographs and to identify risk factors for prolonged healing. The initial tissue response to tagging was minimal, followed by skin loss around the tag, sometimes a degree of swelling, occasional extrusion of blubber, changes in skin colour, local depression formation, tag loss and skin healing over the tag site, sometimes with a depression remaining. At last sighting, most non-integrated and integrated tag sites exhibited small shallow skin depressions (58.8% and 66.7%, respectively). Some exhibited deeper depressions with differing adjacent skin coloration (26.5% and 15.6%, respectively) or barely detectable marks (11.8% and 15.6%, respectively). Mild swellings occasionally persisted at the tag site, but this was uncommon for both tag designs (2.9% and 2.2%, respectively). More severe tissue responses were associated with non-integrated tags and placements lower on the body. This study highlights the importance of using robust tag designs to minimise negative effects from Type-C tags. Furthermore, because tag placement was shown to affect outcome, precision equipment, experienced taggers and vessel operators are critical for optimal deployments.

ecology↗

bioRxiv2024

Before and after delisting: population dynamics of North Atlantic humpback whales over two decades in the Gulf of Maine

Whales are long-lived, slow-reproducing species that were decimated by commercial whaling. Although some populations seem close to recovery, others are challenging to assess. We studied humpback whales (Megaptera novaeangliae) in the Gulf of Maine, an area of the North Atlantic (NA) with well-documented threats. Long-term studies and mark-recapture data were used to estimate humpback whale apparent survival, abundance and population growth from 2000 through 2019. Estimates were derived from a hierarchical, Bayesian state-space model with sex, age, and random time effects on survival while accounting for individual capture probability. Abundance increased from 744 (95% CI: 726-762) in 2000 to 1,706 (95% CI: 1,639-1,771) in 2019, with 4.6% mean annual growth. However, adult males exhibited higher survival and outnumbered adult females by the end of the study. Over time, fewer calves were observed, calf survival varied and the juvenile class declined. These are rare insights into the dynamics underlying whale abundance trends and they revealed similarities to an endangered species that is declining due to environmental and human impacts. The results inform a listing change under the U.S. Endangered Species Act, a mortality event of unprecedented magnitude off the U.S and humpback whale recovery from historical whaling in the NA.

ecology↗

bioRxiv2023

Caller identification and characterization of individual humpback whale acoustic behavior

Acoustic recording tags are biologging tools that provide fine scale data linking acoustic signaling with individual behavior; however, when an animal is in a group, it is challenging to tease apart calls of other conspecifics and identify which individuals produce each call. This, in turn, prohibits robust assessment of individual acoustic behavior including call rates and silent periods, call bout production within and between individuals, and caller location. To overcome this challenge, we simultaneously instrumented small groups of humpback whales on a western North Atlantic feeding ground with sound and movement recording tags. This simultaneous tagging approach enabled us to compare the relative amplitude of each call across individuals and infer caller identity though amplitude differences. Focusing on periods when the tagged animals were isolated from other conspecifics, we were able to assign caller ID for 97% of calls in this dataset. From these labeled calls, we found that humpback whale individual call rates are highly variable across individuals and groups (0-89 calls/h), with calls produced throughout the water column and in bouts with short inter-call intervals (ICI = 2.2 s). Most calls received a likely response from a conspecific within 100 s. These results are important for modelling signal detection range for passive acoustic monitoring and density estimation. Future studies can expand on these methods for caller identification and further investigate the nature of sequence production and counter-calling in humpback whale social calls. Finally, this approach can be helpful for understanding intra-group communication in social groups across other taxa. Summary statementTagging entire humpback whale social groups with sound and movement recording tags allows us to for the first time parse out call behavior within groups and understand individual acoustic behavior.

animal behavior and cognition↗