Dear colleagues, We are writing to share a link to our new paper, recently published in Marine Ecology Progress Series.
Barlow, J. Schorr, G.S., Falcone, E.A., Moretti, D. 2020. Variation in dive behavior of Cuvier's beaked whales with seafloor depth, time-of-day, and lunar illumination. Marine Ecology Progress Series 644: 199-214. https://doi.org/10.3354/meps13350 The paper can be downloaded from: https://www.int-res.com/abstracts/meps/v644/p199-214/ or you can email gschorr(at)marecotel.org, or any of the other authors directly for a copy. ABSTRACT: Depth distributions were analyzed from a study of 19 Cuvier’s beaked whales (Ziphius cavirostris) that were tagged with satellite transmitting tags off southern California. Over 113,000 depth measurements were made over the equivalent of ~200 sampling days. The mean foraging depth was 1,182 m (standard deviation, s.d. = 305 m) and the mean of the maximum depth of all foraging dives is 1,427 m (s.d. = 298 m). Mean foraging depths increased with seafloor depths up to a maximum of ~1,300 m at a seafloor depth of 1,900 m, but decreased slightly to a mean of ~1,200 m at seafloor depths of 2,000-4,000 m. Near-bottom habitat appears to be important for foraging; whales spent ~30% of their foraging time within 200 m of the bottom at seafloor depths of 1,000-2,000 m. However, little foraging time was spent near the bottom at seafloor depths greater than 2,000 m. The percentage of time spent at near-surface depths (< 50 m) was more than twice as high at night (25%) as during the day (12%). Lunar light also appears to affect diving, with 28% of dark nights and only 17% of brightly moon-lit nights spent at these near-surface depths. The apparent avoidance of surface waters during daytime and on brightly moon-lit nights is consistent with avoidance of visual predators. A considerably greater fraction of time was spent foraging at night (24.8%) than during the day (15.7%), possibly due to energetic constraints imposed by predator avoidance during the day Best regards, Greg -- Greg Schorr Research Scientist Marine Ecology and Telemetry Research 2468 Camp McKenzie Trail NW, Seabeck WA 98380-4513 206-931-4638 www.marecotel.org Follow MarEcoTel on Facebook <https://www.facebook.com/marecotel/> Follow MarEcoTel on Twitter <https://twitter.com/marecotel>
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