Data from: The nightscape of the Arctic winter shapes the diving behavior of a pelagic predator ...
Predator-prey interactions in marine ecosystems are dynamically structured by light, which is exemplified by diel vertical migrations of low-trophic level organisms. At high latitudes, the long winter nights provide foraging opportunities for marine predators targeting vertically migrating prey clos...
| Main Authors: | , , , , |
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| Format: | Dataset |
| Language: | English |
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Dryad
2023
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| Subjects: | |
| Online Access: | https://dx.doi.org/10.5061/dryad.zpc866tdh https://datadryad.org/stash/dataset/doi:10.5061/dryad.zpc866tdh |
| Summary: | Predator-prey interactions in marine ecosystems are dynamically structured by light, which is exemplified by diel vertical migrations of low-trophic level organisms. At high latitudes, the long winter nights provide foraging opportunities for marine predators targeting vertically migrating prey closer to the surface at night while minimizing energy expenditure, but there is limited documentation of such diel patterns under extreme light regimes. To address this knowledge gap, we recorded the diving behavior of 17 harbour porpoises just south of the Arctic circle in West Greenland, from summer to winter. Unlike classical diel vertical migration, the porpoises dove three times deeper at night and the frequency of deep dives (>100 m) increased tenfold as they entered the darkest months. The daily mean depth was negatively correlated with daylength, confirming this reverse diel migration and suggesting an increased activity—presumably to target prey at greater depths—when approaching the polar night. Our ... : (a) Animal instrumentation Between 2012 and 2014, 17 harbour porpoises were live-captured on the continental shelf approximately 50 km south-west of Maniitsoq, West Greenland (Fig. 1). Following Nielsen’s et al.’s procedure19, the individuals were instrumented with two types of satellite transmitters (SPLASH and MK10, Wildlife Computers, Redmond, WA, USA). Details on the tagging procedure and tag’s specifications can be found in Nielsen et al. (2019). The study was performed with permission from the Government of Greenland, permit no. 2012-069733, Doc. 1265044. (b) Identification of diel patterns All analyses were conducted using R software version 4.3.0 [39]. To investigate diel patterns in the diving behavior, sunlight phases (times of sunrise, dusk, day, dawn and sunset) were extracted at each individual’s location using the suncalc package [40] in R . For the five tags that were retrieved, no coordinates were stored in the tags. Satellite-relayed Argos coordinates (from the low-resolution datasets) were ... |
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