Occurrence of Guiana dolphin (<scp><i>Sotalia guianensis</i></scp>) in southeast of Brazil: Driven by prey distribution or human fishing activity?

Godoy, Daniela Ferro de; Mendonça, Jocemar Tomasino; Andriolo, Artur

doi:10.1002/aqc.3367

Cited by 6 publications

(5 citation statements)

References 40 publications

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“…A previous study suggested a high abundance of Guiana dolphins in the SP, primarily occupying interior bays and channel systems for feeding, and mainly interacting with traditional fishing gear known as ‘curral’ in this area (see Torres & Beasley, 2003). This fishing gear does not appear to pose a threat to Guiana dolphins, and a similar interaction has been reported in other regions of Brazil (Ferro de Godoy et al, 2020; Monteiro‐Filho, 1995). However, population information for more open coastal areas along the Amazon Atlantic coast is lacking, necessitating further studies to confirm this supposition.…”

Section: Discussionsupporting

confidence: 80%

“…In the dry season, the drought within the bay allows marine waters to enter, increasing the probability of strandings in the inner areas of the MB. Habitat use and changes in preferential areas driven by shifts in the abundance of major prey, seasonal salinity gradient and foraging strategies have been previously indicated for populations of Guiana dolphins from Eastern and Southern Brazil (Ferro de Godoy et al, 2020;Rodrigues et al, 2020;Wedekin et al, 2010).…”

Section: Seasonalitymentioning

confidence: 95%

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Ups and downs: An insight on the stranding pattern of Guiana dolphins, Sotalia guianensis, in the Amazon Estuary, Northern Brazil

Ruenes,

Costa,

Laeta

et al. 2024

Aquatic Conservation

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Long‐term systematic records of cetacean strandings are valuable indicators of temporal responses of specific cetacean populations and communities to natural or anthropogenic pressures. They also help guide management objectives and conservation actions. Generalized additive models (GAMs) were used to analyse 10 years of systematic and opportunistic surveys of Guiana dolphin strandings in the Amazon Estuary region, Northern Brazil. The spatial distribution of strandings was assessed through kernel density maps, and age‐at‐death structure of this population was described. The model results revealed marked seasonality in the strandings and, by extension, the mortality of Guiana dolphins in the Amazon Estuary. This seasonality varied between the inner estuarine regions and Atlantic coastal area, reflecting the environment's characteristics. Long‐term decline of strandings in the Amazon Estuary inner region and unusual high mortality of young sexually mature individuals were detected. These results, besides the high stranding rate detected for the species, are mostly attributed to the species' interaction with intense fishing activity in the region. Conservation efforts should consider the seasonality of Guiana dolphin strandings in the Amazon Estuary. The systematic monitoring of strandings, especially in high‐frequency areas, is recommended for assessing long‐term species mortality. Additionally, implementing management actions related to the species' interaction with fishing activities, such as regulatory enhancements, gillnet modifications and seasonal no‐fishing zones, is advised. Educational campaigns targeting fishermen and riverine communities are essential to reduce bycatch and the folkloric use of the species. This study underscores the effectiveness of stranding data as a source of biological and ecological information, and as a tool for understanding human actions affecting coastal populations of aquatic mammals. It emphasizes the need for urgent studies to characterize this population, clarify the influence of bycatch as an anthropogenic pressure and implement effective conservation actions to preserve the Guiana dolphin population.

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Section: Discussionsupporting

confidence: 80%

Section: Seasonalitymentioning

confidence: 95%

Ups and downs: An insight on the stranding pattern of Guiana dolphins, Sotalia guianensis, in the Amazon Estuary, Northern Brazil

Ruenes,

Costa,

Laeta

et al. 2024

Aquatic Conservation

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“…A baixa variação no número de indivíduos nos grupos também foi observada (SANTOS; ROSSO, 2007). Outros dados apontaram a relação positiva da presença do boto-cinza e os cercos fixos e negativa com as redes de emalhe (GODOY et al, 2020).…”

Section: Sotalia Guianensis Boto-cinza E Pontoporia Blainvillei Toninhaunclassified

Pesca artesanal com emalhe de superfície e encalhes de megafauna

Jankowsky

Martins

Prado

et al. 2023

S&N

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A captura incidental é um tema de grande relevância mundial, permeado por conflitos entre interesses de conservação e pesca. Este conflito no Brasil relaciona-se especialmente ao regramento da pesca artesanal com emalhe de superfície e a captura incidental da megafauna. Para subsidiar a gestão e transformação desse conflito, analisou-se a relação entre desembarques da pesca artesanal com emalhe de superfície e os encalhes de megafauna com morte. Foram utilizados os bancos de dados do monitoramento pesqueiro e do monitoramento de praias de São Paulo entre 2015 e 2021, correspondentes a Chelonia mydas, Caretta caretta, Lepidochelys olivacea, Pontoporia blainvillei e Sotalia guianensis. As análises incluíram (i) panorama dos desembarques pesqueiros com emalhe de superfície e encalhes com mortes de cada espécie durante os anos (ii) testes de correlação entre as variáveis para regiões Norte, Centro e Sul (iii) análise de regressão para os municípios nas regiões que apresentaram correlação positiva estatisticamente significativa. A distribuição do número de desembarques não apresentou sobreposição com a distribuição dos encalhes. Nos testes de correlação, somente os encalhes de C. mydas, na região Norte e Sul, S. guianensis no Sul e P. blainvillei no Centro apontaram relação com os desembarques. A análise de regressão foi significativa para C. mydas e S. guianensis. Nos municípios, C. mydas apresentou resultado estatisticamente significativo em São Sebastião, Ubatuba, Ilha Comprida e Cananéia e S. guianensis em Cananéia. Entretanto, a regressão explicou uma pequena parte da mortalidade e outros fatores de impacto foram apontados. Recomenda-se medidas de ordenamento não proibitivas, estudos participativos e aplicação de métodos diretos de avaliação da interação da pesca com a megafauna, associado a fatores ambientais, bem como análises de outros impactos sobre a megafauna.

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“…Between 1997 and 2021, 164 publications documented the scale of marine mammal bycatch, including fishery and gear-specific bycatch estimates (Julian and Beeson, 1998;Allen, 2000;D'Agrosa et al, 2000;Ortega-Argueta et al, 2005). Marine mammal bycatch is spatially variable, with larger bycatch estimates coinciding with areas of higher marine mammals or fish (prey species) abundance (Lewison et al, 2004(Lewison et al, , 2014de Godoy et al, 2020;Baird et al, 2021), reflecting the increasing resource overlap between marine mammals and fishery operations. In many regions, spatial, temporal, and oceanographic factors affect bycatch.…”

Section: Direct Interactions: Bycatchmentioning

confidence: 99%

Marine Mammal Interactions With Fisheries: Review of Research and Management Trends Across Commercial and Small-Scale Fisheries

et al. 2022

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Marine mammal interactions with fisheries, such as bycatch and depredation, are a common occurrence across commercial and small-scale fisheries. We conducted a systematic review to assess the management responses to marine mammal interactions with fisheries. We analyzed literature between 1995 and 2021 to measure research trends in studies on direct and indirect interactions for: (i) high and low to middle-income countries, (ii) fishery operations (commercial and small-scale), and (iii) taxonomic groups. Management responses were categorized using the framework described previously in peer-reviewed studies. Marine mammal bycatch remains a major conservation concern, followed by marine mammal depredation of fishing gear. A high proportion of studies concentrated on commercial fisheries in high-income countries, with an increase in small-scale fisheries in low to middle-income countries between 1999 and 2020. The insufficient understanding of the social dimensions of interactions and the inevitable uncertainties concerning animal and human behaviors are major challenges to effective management. Despite the key role of human behavior and socioeconomics, we found only eight articles that incorporate human dimensions in the management context. Integrating social dimensions of marine mammal interactions with fisheries could help in setting pragmatic conservation priorities based on enhanced understanding of critical knowledge gaps. An area-specific adaptive management framework could be an effective tool in reducing the risk to marine mammals from fisheries by coupling technical solutions with socio-economic and political interventions. We conclude that despite the vast body of literature on this subject, a “silver bullet” management solution to marine mammal interactions with fisheries does not yet exist.

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Occurrence of Guiana dolphin (Sotalia guianensis) in southeast of Brazil: Driven by prey distribution or human fishing activity?

Cited by 6 publications

References 40 publications

Ups and downs: An insight on the stranding pattern of Guiana dolphins, Sotalia guianensis, in the Amazon Estuary, Northern Brazil

Ups and downs: An insight on the stranding pattern of Guiana dolphins, Sotalia guianensis, in the Amazon Estuary, Northern Brazil

Pesca artesanal com emalhe de superfície e encalhes de megafauna

Marine Mammal Interactions With Fisheries: Review of Research and Management Trends Across Commercial and Small-Scale Fisheries

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