Artisanal fishers' perceptions of the ecosystem services derived from a dolphin-human cooperative fishing interaction in southern Brazil

Machado, Alexandre M. S.; Daura‐Jorge, Fábio G.; Herbst, Dannieli Firme; Simões‐Lopes, Paulo C.; Ingram, Simon; Castilho, Pedro Volkmer de; Peroni, Nivaldo

doi:10.1016/j.ocecoaman.2019.03.003

Cited by 22 publications

(27 citation statements)

References 53 publications

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“…1). Dolphin-fisher foraging interactions frequently occur in at least five fishing sites close to the Tubarão River and the inlet channel (details in [22]). Interviews were conducted around four of these five fishing sites, when fishers were waiting for dolphins to interact (Tesoura and Toca da Bruxa across the inlet channel, Ponta das Pedras and Barra inside the lagoon; Fig.…”

Section: Research Area and Data Collectionmentioning

confidence: 99%

“…To obtain a consensus measure per fisher, we calculated the Average Consensus Index (ACI) as the average of all CIs of a given interviewee with all other pairs of fishers (adapted from [38]). We fitted a beta generalized linear model (GLM), with a logit link function [39], to model ACI as a function of the following fishers' characteristics: age, the main fishing site-given that the lagoon sites are used by more professional fishers, while the channel sites also by opportunists and amateurs fishers [22]-, whom they learned how to fish Fig. 1 The research area: The lagoon system in Laguna, southern Brazil.…”

Section: Consensus Among Fishersmentioning

confidence: 99%

“…Although it remains poorly understood how this interaction alters fishers' behavior, it is clear that fishers perceive and rely on the dolphins' behavior. They synchronize their actions with the dolphins' actions [17] and reported at least nine ecosystem services from this interaction, including provision, cultural, and social benefits [22]. Interestingly, fishers also report being able to identify dolphins, classifying them as "good" dolphinsthose that often interact with them, and "bad" dolphinsthose that do not [23].…”

Section: Introductionmentioning

confidence: 99%

“…The intricate knowledge fishers seem to have on dolphins in Laguna is then an opportunity to understand how the local knowledge about these animals is built individually. However, the fishing community that interacts with dolphins is very heterogeneous, economically, and socially, as well as in their historical engagement in the interactive tactic [22,23]. For instance, fishers vary in terms of experience in foraging with dolphins.…”

Section: Introductionmentioning

confidence: 99%

“…For instance, fishers vary in terms of experience in foraging with dolphins. Fishers also fit into different socio-economic profiles: (a) the professionals-those who rely on the fishing activity as the main source of income; (b) the opportunists-those who tend to interact with dolphins only during the mullet season; (c) and the amateurs-those who engage in the fishing with dolphins all year long, but as a hobby, since their main source of income depends on other activities [22]. The analysis of traditional knowledge needs to account for such variability that likely affects the quality and accuracy of individual perceptions on their systems [22,28,34].…”

Section: Introductionmentioning

confidence: 99%

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The ability of artisanal fishers to recognize the dolphins they cooperate with

Rosa

Hanazaki

Cantor

et al. 2020

J Ethnobiology Ethnomedicine

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Background: Human-animal interactions with mutual benefits in the wild are rare. Such positive interactions seem to require an intricate knowledge from the human side on the animals' behavior and their habitat. In southern Brazil, dolphins and human net-casting fishers have specialized in a cooperative foraging, in which fishers report being able to identify and name dolphins. Here, we evaluate the consensus in their ability to recognize the individual dolphins they interact with. By investigating the reliability of this recognition process, we assess the pros and cons of relying on the fishers' traditional knowledge to further understand the behavior and ecology of dolphins at the individual level. We also assess the potential role of traditional knowledge for the maintenance of this unusual interaction. Methods: We interviewed 38 fishers using a semi-structured questionnaire. During each interview, we evaluate their recognition ability of dolphins by showing high-quality photos of dorsal fins of different dolphins, asking questions about the dolphins' behavior and traits, and about how fishers recognize each dolphin. We also evaluated information about the fishers. Different indices were used to measure the fishers' ability to recognize dolphins via photos, and their consensus on individual identification. These indices were modeled as functions of traits of both dolphins and fishers to investigate which ones influence the recognition process. Results: We found that fishers can primarily recognize dolphins by natural marks in the dorsal fin but there was little consensus in recognition. Fishers also tend to repeat the name of the most "popular" dolphins for different photos, indicating low reliability in individual recognition. We also found that fishers who learned from relatives (vertical learning) how to interact with dolphins tend to be more accurate and have higher consensus in dolphin recognition than those fishers who learned from friends (horizontal learning) or individually. Conclusion: Artisanal fishers have a deep understanding of the dolphins and the system they are inserted in. However, the lack of consensus in identifying individual dolphins herein reported indicates that using their traditional knowledge to further understand dolphin behavior and ecology at the individual level requires caution. Our study also suggests that the transmission of this tradition from parents to sons can be crucial to preserve such a unique human-animal positive interaction in its original form.

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Section: Research Area and Data Collectionmentioning

confidence: 99%

Section: Consensus Among Fishersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

The ability of artisanal fishers to recognize the dolphins they cooperate with

Rosa

Hanazaki

Cantor

et al. 2020

J Ethnobiology Ethnomedicine

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Dolphin population specialized in foraging with artisanal fishers requires zero‐bycatch management to persist

Bezamat

Hammond

Castilho

et al. 2021

Aquatic Conservation

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1. The small population paradigm assumes that populations with low numbers of individuals intrinsically have a high probability of extinction. The small population of Lahille's bottlenose dolphins Tursiops truncatus gephyreus that specializes in foraging with artisanal fishers in Laguna, southern Brazil, faces human pressures including bycatch in fishing gear. The viability of this population was modelled over 30 and 100 years under different levels of bycatch, including the current scenario of two bycatches every year, two scenarios with higher incidence of bycatches and three management scenarios. The sensitivity of predicted growth rates to fixed-proportion and observed-variation changes in life history parameters was explored.2. The current scenario predicted a declining population (r = À0.014; λ = 0.986) with a high probability of extinction in the long term (PE = 0.71). A small increase in bycatches would result in a marked increase in the probability of extinction.Management scenarios seem promising, but only the zero-bycatch management scenario would make the difference between a declining and an increasing population.3. As expected for slow-growing species, population growth rate was most sensitive to proportional changes in adult female and juvenile survival. However, considering observed variation in vital rates, population dynamics were most influenced by variation in reproductive rates. 4. To determine the highest priority for management action, another simulation was made of how additional threat scenarios of recognized human activities (i.e. bycatch influencing adult survival and increased underwater noise or pollution influencing calf survival) would affect population dynamics. Population growth rate was very sensitive to changes in adult bycatch (especially females), as expected, and only subtly sensitive to a reduction in calf survival.5. The current level of bycatch is unsustainable. Bycatch needs to be eliminated to maximize the probability of long-term persistence of this dolphin population.However, this population's persistence could be threatened by natural variation in reproductive rates.

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