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Behavioral repertoire of Lahille’s bottlenose dolphins that interact with artisanal fishers

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Many human cultures involve positive interactions with wildlife in the past and present. Lahille’s bottlenose dolphins (Tursiops gephyreus), for example, have developed tactics for coastal and estuarine foraging, which sustains a fishing practice known as “cooperative fishing” by traditional fishers in estuaries of southern Brazil. Here, we use aerial footage to describe the behavioral repertoire of the Lahille’s bottlenose dolphins and how it relates to the frequency of net casting by fishers in the Tramandaí Inlet. From nearly 8 h of footage from June 2017 to May 2018, we mainly observed dolphins foraging in the estuary inlet when fishers were present along the shoreline. Dolphins performed at least 27 clearly distinct behaviors and three types of movement patterns. A generalized additive model supported that the fishers interpret a subset of this repertoire (64%) as cues for casting their nets. The behavioral overview of the Lahille’s bottlenose dolphins presented here demonstrates not only a diverse repertoire for this population, but also its clear influence on fishers’ activities. Scientific and traditional perspectives should be integrated to better understand the ecological significance of this “cooperative fishing” for both dolphin populations and fishers that depend on them. Significance statement Interactions between different species can be very complex. It is a three-dimensional universe that comprises the behavioral and ecological characteristics of both sides, and then the dynamic they create together. In the case of the “cooperative fishing” between fishers and dolphins in southern Brazil, we still have one dimension to disclose in detail: the dolphins’ behavioral repertoire. Using aerial videos from a drone, we were able to shed light on how those dolphins behave and also how fishers coordinate their activity in response to the dolphins. We also showed that the dolphins’ behavioral repertoire is more diverse than assumed so far. Results suggest that the “cooperative fishing” seems to be based on the human’s perception of an extensive Lahille’s bottlenose dolphin behavioral repertoire during hunting. The knowledge provided here is essential to track the dynamic of this unique interaction in a given space and time.
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Vol.:(0123456789)
Behavioral Ecology and Sociobiology (2024) 78:31
https://doi.org/10.1007/s00265-024-03443-w
ORIGINAL ARTICLE
Behavioral repertoire ofLahille’s bottlenose dolphins thatinteract
withartisanal fishers
NathaliaSerpa1,2 · GuilhermeFrainer3 · BárbaradosSantos2· GuilhermeA.Bortolotto4 ·
IgnacioB.Moreno1,2,5
Received: 16 August 2023 / Revised: 24 January 2024 / Accepted: 2 February 2024 / Published online: 23 February 2024
© The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024
Abstract
Many human cultures involve positive interactions with wildlife in the past and present. Lahille’s bottlenose dolphins (Tur-
siops gephyreus), for example, have developed tactics for coastal and estuarine foraging, which sustains a fishing practice
known as “cooperative fishing” by traditional fishers in estuaries of southern Brazil. Here, we use aerial footage to describe
the behavioral repertoire of the Lahille’s bottlenose dolphins and how it relates to the frequency of net casting by fishers
in the Tramandaí Inlet. From nearly 8h of footage from June 2017 to May 2018, we mainly observed dolphins foraging in
the estuary inlet when fishers were present along the shoreline. Dolphins performed at least 27 clearly distinct behaviors
and three types of movement patterns. A generalized additive model supported that the fishers interpret a subset of this
repertoire (64%) as cues for casting their nets. The behavioral overview of the Lahille’s bottlenose dolphins presented here
demonstrates not only a diverse repertoire for this population, but also its clear influence on fishers’ activities. Scientific and
traditional perspectives should be integrated to better understand the ecological significance of this “cooperative fishing”
for both dolphin populations and fishers that depend on them.
Signicance statement
Interactions between different species can be very complex. It is a three-dimensional universe that comprises the behavioral
and ecological characteristics of both sides, and then the dynamic they create together. In the case of the “cooperative fishing”
between fishers and dolphins in southern Brazil, we still have one dimension to disclose in detail: the dolphins’ behavioral
repertoire. Using aerial videos from a drone, we were able to shed light on how those dolphins behave and also how fish-
ers coordinate their activity in response to the dolphins. We also showed that the dolphins’ behavioral repertoire is more
diverse than assumed so far. Results suggest that the “cooperative fishing” seems to be based on the human’s perception of
an extensive Lahille’s bottlenose dolphin behavioral repertoire during hunting. The knowledge provided here is essential to
track the dynamic of this unique interaction in a given space and time.
Keywords Behavioral repertoire· Hunting strategy· Interspecific interaction· Traditional fishing· Tursiops gephyreus·
Unmanned aerial vehicle
Communicated by S. Parks
* Nathalia Serpa
serpabn@gmail.com
1 Programa de Pós-Graduação em Biologia Animal,
Departamento de Zoologia, Universidade Federal doRio
Grande doSul, PortoAlegre, Brazil
2 Centro de Estudos Costeiros, Limnológicos e Marinhos
(CECLIMAR), Universidade Federal doRio Grande doSul,
Campus Litoral Norte, Imbé, Brazil
3 Centre forStatistics inEcology, Environment
andConservation, University ofCape Town, CapeTown,
SouthAfrica
4 Department ofLife Sciences, Aberystwyth University,
Aberystwyth, UK
5 Departamento Interdisciplinar, Universidade Federal doRio
Grande doSul, Campus Litoral Norte, Tramandaí, Brazil
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