Seasonal flow dynamics exacerbate overlap between artisanal fisheries and imperiled Ganges River dolphins
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Univ Arizona, Sch Nat Resources & EnvironmIssue Date
2020-11-02
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NATURE RESEARCHCitation
Paudel, S., Koprowski, J. L., & Cove, M. V. (2020). Seasonal flow dynamics exacerbate overlap between artisanal fisheries and imperiled Ganges River dolphins. Scientific Reports, 10(1), 1-12.Journal
SCIENTIFIC REPORTSRights
© The Author(s) 2020. Open Access. This article is licensed under a Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
Here we quantify the effects of artisanal fisheries on the ecology of a small cetacean, the Ganges River dolphin (Platanista gangetica gangetica, GRD), in a large river system of Nepal. We examine the size-classes of fisheries' catches, behavioural changes in GRD in response to fishing activities, and diel overlap between GRD and fishing activity. We observed high human exploitation rates (>60% of the total catch per effort) of GRD-preferred prey sizes, indicating risks of high resource competition and dietary overlap, especially during the low water season when resource availability is reduced. Competitive interactions in the feeding niches during the low water season, plus temporal overlap between the peak exploitation and critical life-history events (e.g., reproduction), likely have ecological consequences. Furthermore, we detected 48% (95% CI 43-52%) increase in the chance of behavioural changes among dolphins exposed to anthropopressure (fishing activity), risking social behaviour impairment in exposed dolphins. The higher diel overlap and increased diel coefficient as the surveys progressed towards the monsoon season suggest temporal shifts in GRD socio-behavioural states and seasonal effects on resource partitioning, respectively. This work identifies drivers of small cetaceans-fisheries interactions and their consequences, and can be used to help reduce biologically significant fishing impacts on small cetaceans. Mitigation strategies, together with river sanctuary and distanced-based approaches, should be urgently included in a framework of ecosystem-based management.Note
Open access journalISSN
2045-2322EISSN
2045-2322PubMed ID
33139770Version
Final published versionae974a485f413a2113503eed53cd6c53
10.1038/s41598-020-75997-4
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Except where otherwise noted, this item's license is described as © The Author(s) 2020. Open Access. This article is licensed under a Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
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