Biology subjects

Podolskiy, E. A.

Publications and source records attributed to Podolskiy, E. A..

4 recordsLinked to original sources

bioRxiv2026

Estimating age and annual tooth growth rates in narwhals (Monodon monoceros) using computed tomography

The spiraling tooth of the narwhal (Monodon monoceros) has long intrigued scientists, but the growth rates of its "tusk" are poorly constrained due to the difficulty to age narwhal. To learn more about the population dynamics and life history of this exploited species, previous studies have used sectioned teeth to age narwhals and calibrate other ageing methods based on aspartic acid racemization, radiocarbon or trace element analysis. However, few such studies have been conducted due to the method's difficulty and the need to sacrifice the tooth. In this study, computed tomography (CT) was used on five teeth as a non-destructive means of estimating the age of narwhals, revealing different growth rates between erupted and embedded teeth during adolescence. Moreover, in combination with our reanalysis of all relevant literature, CT data clarify the annual growth rates of narwhal tusks, which peak before the age of 10 (~100 mm yr-1). This approach will be useful for investigating private and museum collections, and might also better constrain the use of trace element proxies in narwhal teeth and support sustainable harvest management.

zoology↗

bioRxiv2026

Seafloor video-acoustic monitoring in a Greenlandic glacial fjord records hyperbenthos, backward-swimming fish, and narwhals

Autonomous video-acoustic monitoring at the sea-floor can improve our understanding of poorly documented ecosystems and help interpret active or passive acoustic data, but it has been rarely carried out, particularly in the Arctic. This study deployed a video camera synchronized with a hydrophone, combined with red lights and other oceanographic instrumentation, on the bottom of a glacial fjord in Inglefield Bredning, northwest Greenland (to 260 m water depth). Through manual review and automatic analysis of high-frequency images (30 fps) and audios (96 kHz), the conditions and biodiversity near the sea-floor were quantified. The data revealed a highly turbulent environment with abundant suspended particles and fibers, with 88% of 478 detected organisms being Amphipoda, Copepoda, Hydrozoa, and Chaetognatha. Amongst the other observed animals were Decapoda, Liparidae, Pterotracheoidea, Ctenophora, and curious narwhals (Monodon monoceros). The number of marine snow particles was highly variable through time and could change up to twofold within several hours. The tide modulated the particle flow direction and speed. Overall, the results show that portable moorings with video recorders are an important tool for exploration of the Arctic seafloor.

ecology↗

bioRxiv2025

Inuit Hunt as a Platform for Observing Narwhals (Monodon monoceros) in Inglefield Bredning (Kangerlussuaq), Greenland

Direct observations of narwhals are scarce but needed for understanding this ecologically and culturally important species. Here, we describe the first boat-based observations of narwhals in their key summering ground in Greenland (Inglefield Bredning), collected during an Inuit hunt and enhanced by drone air support. During 3--8 August 2024, 506 narwhal observations were made from a semi-stationary boat at the head of the fjord, of which 58 were filmed with a drone. Boat observations near the north side of the fjord indicated that narwhals preferentially traveled outward to the west, with a clear link to currents. The presence of narwhals was more likely in the second half of a day but was highly intermittent, with waiting times for observers reaching as much as 15-28 h between sightings, highlighting the patience needed to observe and catch a narwhal. We also recorded a motionless sleep-like behavior at the surface, known as pugginnartoq (Greenlandic) for narwhals. Aerial drone support was useful for revealing unseen-from-sea-surface features and behaviors, which we describe as potentially interesting for future investigation. For example, drone imagery revealed that 71{+/-}7% of narwhals had tusks, with a mean tusk-to-body-length ratio of 0.23{+/-}0.01. Overall, this report shows that hunting expeditions integrated with scientific methods provide important insights and inspire further work.

zoology↗

bioRxiv2022

Strange attractor of a narwhal (Monodon monoceros)

Detecting structures within the continuous diving behavior of marine animals is challenging, and no universal framework is available. We captured such diverse structures using chaos theory. By applying time-delay embedding to exceptionally long dive records (83 d) from the narwhal, we reconstructed the state-space portrait. Using measures of chaos, we detected a diurnal pattern and its seasonal modulation, classified data, and found how sea-ice appearance shifts time budgets. There is more near-surface rest but deeper dives at solar noon, and more intense diving during twilight and at night but to shallower depths (likely following squid); sea-ice appearance reduces rest. The introduced geometrical approach is simple to implement and potentially helpful for mapping and labeling long-term behavioral data, identifying differences between individual animals and species, and detecting perturbations.

biophysics↗