Publication Date:
2022-10-20
Description:
© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Caruso, F., Hickmott, L., Warren, J. D., Segre, P., Chiang, G., Bahamonde, P., Español-Jiménez, S., Li, S., & Bocconcelli, A. Diel differences in blue whale (Balaenoptera musculus) dive behavior increase nighttime risk of ship strikes in northern Chilean Patagonia. Integrative Zoology, (2020): 1-18, doi:10.1111/1749-4877.12501.
Description:
The northern Chilean Patagonia region is a key feeding ground and a nursing habitat in the southern hemisphere for blue whales (Balaenoptera musculus). From 2014 to 2019, during 6 separate research cruises, the dive behavior of 28 individual blue whales was investigated using bio‐logging tags (DTAGs), generating ≈190 h of data. Whales dove to significantly greater depths during the day compared to nighttime (day: 32.6 ± 18.7 m; night: 6.2 ± 2.7 m; P 〈 0.01). During the night, most time was spent close to the surface (86% ± 9.4%; P 〈 0.01) and at depths of less than 12 m. From 2016 to 2019, active acoustics (scientific echosounders) were used to record prey (euphausiids) density and distribution simultaneously with whale diving data. Tagged whales appeared to perform dives relative to the vertical migration of prey during the day. The association between diurnal prey migration and shallow nighttime dive behavior suggests that blue whales are at increased risk of ship collisions during periods of darkness since the estimated maximum ship draft of vessels operating in the region is also ≈12 m. In recent decades, northern Chilean Patagonia has seen a large increase in marine traffic due to a boom in salmon aquaculture and the passenger ship industry. Vessel strike risks for large whales are likely underestimated in this region. Results reported in this study may be valuable for policy and mitigation decisions regarding conservation of the endangered blue whale.
Description:
This work was conducted under Chilean research permit PINV 38–2014 Ballena Azul, Golfo Corcovado, from the Ministerio de Economia, Fomento y Turismo, Subsecreteria de Pesca y Acuicultura. We would like to thank the crews of the vessels Centinela, Khronos and Solidaridad for their involvement in the fieldwork. Special thanks to Rafaela Landea‐Briones, Gloria Howes, Esteban Tapia Brunet, Pepe Montt, Thomas Montt, and Daniel Casado for helping and welcoming us in Patagonia. Thanks to MERI Foundation and their students Carlos Cantergiani, Andrea Hirmas and Elvira Vergara for their support and contributions to field efforts. We extend our gratitude to our collaborators Laela Sayigh, Michael Moore, Daniel Zitterbart, Frants Jensen, Aran Mooney, John Durban, Jeremy Goldbogen, and Dave Cade. Thanks to WHOI for financial and technical support. The data analysis and paper writing was financially supported by the National Key Research and Development Program of China (Grant number 2016YFC0300802); the biodiversity investigation, observation and assessment program (2019‐2023) of the Ministry of Ecology and Environment of China; and Indian Ocean Ninety‐east Ridge Ecosystem and Marine Environment Monitoring and Protection, supported by the China Ocean Mineral Resources R&D Association (no. DY135‐E2‐4). Additionally, FC thanks the President's International Fellowship Initiative (PIFI) of the Chinese Academy of Sciences.
Keywords:
Bio‐logging tags
;
Blue whale
;
Diving profile
;
Ocean conservation
;
Prey distribution
Repository Name:
Woods Hole Open Access Server
Type:
Article
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