Clues of cultural transmission in cooperative foraging between artisanal fishermen and bottlenose dolphins, Tursiops truncatus (Cetacea: Delphinidae)

Simões‐Lopes, Paulo C.; Daura‐Jorge, Fábio G.; Cantor, Maurício

doi:10.1590/s1984-4689zool-20160107

Cited by 21 publications

(25 citation statements)

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“…We defined two foraging tactics: cooperative foraging, when dolphins were interacting with fishermen ( i.e ., driving prey schools towards fishermen and performing stereotyped behaviors associated with the interaction, as described in Simões‐Lopes et al . ); and noncooperative foraging, when dolphins were foraging by themselves ( i.e ., diving frequently and asynchronously and in various directions). We attempted to photograph the dorsal fin of all dolphins in the group, taking as many photos as possible of both sides and without individual preferences, following protocols for small cetaceans (Würsig and Jefferson ).…”

Section: Methodsmentioning

confidence: 99%

“…) frequently herd mullet shoals towards a line of fishermen and “signal” with specific behavioral displays when and where fishermen should cast their nets (Simões‐Lopes et al . ). Dolphins that share this foraging tactic associate more often with each other than with the rest of the population, dividing the society into social units of cooperative and noncooperative dolphins (Daura‐Jorge et al .…”

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confidence: 97%

“…In Laguna, southern Brazil, a very distinctive foraging tactic of free‐living Lahille's bottlenose dolphins ( Tursiops truncatus gephyreus ) involves synchronized interaction with net‐casting fishermen (Simões‐Lopes et al . , ). A subset of dolphins from this small, resident (see Daura‐Jorge et al .…”

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confidence: 99%

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The influence of cooperative foraging with fishermen on the dynamics of a bottlenose dolphin population

Bezamat

Simões-Lopes

Castilho

et al. 2018

Marine Mammal Science

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Recent years have seen an increasing interest in individual behavioral variation. However, the implications of such variation for population dynamics are often unknown. We studied the dynamics of a bottlenose dolphin (Tursiops truncatus gephyreus) population from southern Brazil, where some individuals forage cooperatively with artisanal fishermen. We fitted mark-recapture models to 10 yr of photo-identification data to investigate the influence of this foraging specialization on dolphins' population parameters, controlling for sex and ranging behavior. We estimated adult survival to be high (0.949 AE 0.015 SE), weakly influenced by home range size, sex or the frequency of interaction with fishermen. The slightly higher survival probability for individuals with smaller home ranges could stem from the benefits of reduced spatial requirements implied by the specialized foraging. Foraging also influenced the probability of resighting individuals, and there was no temporary or permanent emigration. Abundance fluctuated slightly over the years from 54 (95% CI = 49-59) to 60 (95% CI = 52-69) individuals, with no evident population trend. Despite such apparent population stability, we confirm this population remains small and geographically isolated which may threaten its viability and the viability of its unusual, localized foraging specialization. Our study also illustrates how accounting for individual variation can portray animal population dynamics more realistically.

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Section: Methodsmentioning

confidence: 99%

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confidence: 97%

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The influence of cooperative foraging with fishermen on the dynamics of a bottlenose dolphin population

Bezamat

Simões-Lopes

Castilho

et al. 2018

Marine Mammal Science

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“…The theory of interaction is that the tarrafeiros increase their catch and capture larger individuals by casting their nets over mullet schools herded by bottlenose dolphins, whereas the bottlenose dolphins are able to catch mullets more easily because the throwing nets disrupts the schools (Simões-Lopes et al 1998). This interspecific relationship can be considered cooperation (Pryor et al 1990, Simões-lopes 1991, Simões-Lopes et al 1998, Simões-Lopes et al 2016, being called "cooperative fishery".…”

Section: Introductionmentioning

confidence: 99%

“…The few fishery studies available at TRE did not cover a one-year period and have focused on the interaction between bottlenose dolphins and fishermen per se, particularly the behavior of the bottlenose dolphins and their relationship with the fisherman (Simões-Lopes 1991, Simões-Lopes et al 1998, Zappes et al 2011, Simões-Lopes et al 2016. The temporal and quantitative assessment of catches and interspecific relationships of cooperative fishery with environmental factors are fundamental to support sustainable management proposals that ensure the maintenance of this rare artisanal fishery.…”

Section: Introductionmentioning

confidence: 99%

No mullet, no gain: cooperation between dolphins and cast net fishermen in southern Brazil

Santos¹,

Lemos²,

Vieira³

2018

Zoologia

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We report on the interaction between common bottlenose dolphins, Tursiopstruncatus (Montagu, 1821) and cast net fishermen in southern coast of Brazil. The fishery was monitored in the mouth of the Tramandaí River Estuary to investigate the seasonality of catches and their relationships with a set of variables: presence/absence and number of bottlenose dolphins, fishing area, temperature, salinity, wind and water flow direction in the channel. The mullet, Mugilliza Valenciennes, 1836 is the target species and was the dominant fish in the catches (77% of total catch; 50% in frequency; 0.2 ind. x f-1). The use of GLM models helped to reveal that the number of the bottlenose dolphins, time of year (months) and spatial variation of fishing activity were the main factors explaining the presence and abundance of mullet in the fishermen’s catches. The presences of bottlenose dolphins in the fishing area raise the probability of fishermen catch larger number of mullets with smaller fishing effort. However, the size of the mullet is influenced basically by seasonality. The mullets are the “currency” of bottlenose dolphins and fishermen interaction. There are reasons for concern about the sustainability of the southern Brazilian M.liza stock, once the decrease of this fishing resource can lead this rare and traditional fishery to the extinction.

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Spatial behavioural response of coastal bottlenose dolphins to habitat disturbance in southern Brazil

Agrelo

Daura‐Jorge

Bezamat

et al. 2019

Aquatic Conservation

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A small population of coastal bottlenose dolphins (Tursiops truncatus gephyreus) inhabits the inland waters of Laguna, southern Brazil. A subset of this population interacts with artisanal fishermen. This specialized foraging tactic structures dolphin society into ‘cooperatives' (participants of the interaction) and ‘non‐cooperatives' (non‐participants). Between 2012 and 2015, a bridge was constructed in Laguna over an important core area for dolphins. Photo‐identification and georeferenced data collected on boat surveys, conducted both before and during bridge construction, were used to evaluate changes in both ‘cooperative' and ‘non‐cooperative' dolphin distribution. Changes in dolphin distribution were analysed with kernel densities and hurdle models. A grid of 120 cells of area 1 km2 was used to model dolphin distribution, and the minimum distance from the grid cell centre to the bridge and to the area of gillnet use were defined as explanatory variables of human activities. Habitat descriptors (depth and distance) from the lagoon margin were also considered in the model procedure. Dolphin distribution patterns shifted between periods. A core area used by ‘non‐cooperative' dolphins near the bridge construction works disappeared. The effects of habitat descriptor and anthropogenic activity on dolphin distribution also differed between periods. Before bridge construction, the abundance of ‘non‐cooperative' dolphin was higher close to the bridge area (p < 0.05). During bridge construction, the presence of ‘cooperative' and ‘non‐cooperative' dolphins decreased significantly with the distance from gillnet fishing activity (p < 0.01 and p < 0.001 respectively). This study highlights the importance of accounting for individual variations in response when assessing the effects of a habitat disturbance, or when implementing conservation plans.

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Clues of cultural transmission in cooperative foraging between artisanal fishermen and bottlenose dolphins, Tursiops truncatus (Cetacea: Delphinidae)

Cited by 21 publications

References 7 publications

The influence of cooperative foraging with fishermen on the dynamics of a bottlenose dolphin population

The influence of cooperative foraging with fishermen on the dynamics of a bottlenose dolphin population

No mullet, no gain: cooperation between dolphins and cast net fishermen in southern Brazil

Spatial behavioural response of coastal bottlenose dolphins to habitat disturbance in southern Brazil

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