Diel differences in blue whale (Balaenoptera musculus) dive behavior increase nighttime risk of ship strikes in northern Chilean Patagonia
Abstract
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.
Citation
Caruso , F , Hickmott , L , Warren , J D , Segre , P , Chiang , G , Bahamonde , P , Español-Jiménez , S , Li , S & Bocconcelli , A 2020 , ' Diel differences in blue whale ( Balaenoptera musculus ) dive behavior increase nighttime risk of ship strikes in northern Chilean Patagonia ' , Integrative Zoology , vol. Early View . https://doi.org/10.1111/1749-4877.12501
Publication
Integrative Zoology
Status
Peer reviewed
ISSN
1749-4877Type
Journal article
Rights
Copyright © 2020 The Authors. Integrative Zoology published by International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd. This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial‐NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made.
Description
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.Collections
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