Guiana Dolphin (Sotalia guianensis) in the southern Gulf of Venezuela: Seasonal distribution, group size, and habitat use

Espinoza-Rodríguez, Nínive; Turris-Morales, Kareen De; Shimada, Takahiro; Barrios-Garrido, Héctor

doi:10.1016/j.rsma.2019.100874

Cited by 7 publications

(13 citation statements)

References 40 publications

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“…Further research is needed to have a better perspective about key threats of the Guiana dolphin MU in the Maracaibo Lake System, especially in the following human-related pressures: heavy metal bioaccumulation, boat noise effects, direct capture, habitat degradation, artisanal fishery impacts, oil extraction, and transportation activities, algal and duckweed blooms, and marine debris interaction (entanglement and ingestion). All of these mentioned potential threats have been previously described in the study area (Delgado-Ortega, 2012; Barrios-Garrido et al, 2015Sanchez and Briceño, 2017;Espinoza-Rodríguez et al, 2019) (Figure 2).…”

Section: Recommendations and Future Management Plansmentioning

confidence: 54%

“…Guiana dolphins present two main population cores in the Maracaibo Lake System (Caballero et al, 2010;Barrios-Garrido et al, 2015). The first one in the Gulf of Venezuela; where there is an estimated abundance of 1.34 individuals per km 2 , with groups composed of 2-5 individuals, and aggregations as large as one-hundred (Espinoza-Rodríguez et al, 2019). The second population core inside the Maracaibo Lake System has an abundance estimation of 1.66 individuals per km 2 , within an area of 249.2 km 2 , based on research carried out in the western-central area of this aquatic habitat (Delgado-Ortega, 2012).…”

Section: Main Findings-regional Problems and Local Pressuresmentioning

confidence: 99%

“…Genetic identification to solve the links between northern (Gulf of Venezuela) and southern (Maracaibo Lake) populations are needed (Caballero et al, 2018). Further research is needed in the area to improve current knowledge of the species, including in other data-poor zones; e.g., Capatarida (Falcon State), and Ceuta (Zulia state) (Espinoza-Rodríguez et al, 2019). Conservation strategies focused on Guiana dolphins in the Maracaibo Lake System are strongly recommended (e.g., stranding network, specialized research centers, among others); moreover, a risk assessment of Guiana dolphin mortality is required to inform management decisions.…”

Section: Recommendations and Future Management Plansmentioning

confidence: 99%

“…However, within the Maracaibo Lake MU, there are still important knowledge gaps regarding the habitat use, threats, distribution, and ecology of the Guiana dolphin Espinoza-Rodríguez et al, 2019). The Guiana dolphin MU in the Maracaibo Lake is an isolated population center that needs to be investigated due to its genetic and anatomic uniqueness (Caballero et al, 2007(Caballero et al, , 2010(Caballero et al, , 2018De Turris-Morales et al, 2010a).…”

Section: Introductionmentioning

confidence: 99%

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Guiana Dolphin (Sotalia guianensis) in the Maracaibo Lake System, Venezuela: Conservation, Threats, and Population Overview

2021

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The Guiana dolphin (Sotalia guianensis) home range is located across Central and South American countries, in coastal habitats in the Caribbean and Atlantic Ocean. Its distribution is scattered, with multiple population centers which are under threats that vary based on local realities. We compiled and assessed biological data from multiple sources (published and unpublished data) to improve our understanding regarding the Maracaibo Lake Management Unit, which is an isolated and unique population core of this species. We identified at least two distinguishable population centers throughout the Maracaibo Lake System, one in the northern portion—in the Gulf of Venezuela, and another in the southern portion of the Maracaibo Lake itself. Both centers have differences in some biological aspects (e.g., group size and habitat use), but similarities in the human-induced pressures (e.g., intentional take, habitat degradation, and traditional use). We detailed the uses of Guiana dolphin (consumptive and non-consumptive) by community members, including the use as talismans for indigenous fishers and consumption of its meat as a religious belief (Easter period), and dolphin watching tours carried out by local companies. In one artisanal port, at least 15 animals are intentionally taken annually to be used for local consumption, shark-bait, or trade; however, we acknowledge that this annual take is likely an underestimate. Further research is needed to clarify how and at what magnitude mentioned and other key-threats are impacting over Guiana dolphin MU in the Maracaibo Lake System.

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Section: Recommendations and Future Management Plansmentioning

confidence: 54%

Section: Main Findings-regional Problems and Local Pressuresmentioning

confidence: 99%

Section: Recommendations and Future Management Plansmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Guiana Dolphin (Sotalia guianensis) in the Maracaibo Lake System, Venezuela: Conservation, Threats, and Population Overview

2021

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“…Different populations of the species have been accessed for these data in Brazil, at the Baía do Emboraí (Pará state), Baía de Guanabara and Baía de Sepetiba (Rio de Janeiro state), Cananéia estuary (São Paulo state), Paranaguá and Guaratuba estuaries (Paraná state) and Baía de Babitonga (Santa Catarina state) (Santos et al ., 2010 a ; Azevedo et al ., 2017; Monteiro-Filho et al ., 2018). Population estimates are also available for Venezuela (Gulf of Venezuela), Colombia (Gulf of Morrosquillo) and Nicaragua (Miskito Cayos Reserve) (Santos et al ., 2010 a ; Espinoza-Rodríguez et al ., 2019).…”

Section: Introductionmentioning

confidence: 99%

Assessing Guiana dolphin abundance and density in the Southwestern Atlantic: insights from conservation areas

Almeida¹,

Percequillo²,

Rollo³

2023

J. Mar. Biol. Ass.

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Accurate demographic data play a critical role in implementing conservation strategies and identifying key areas for species preservation. The population abundance and density of Sotalia guianensis were estimated in the estuarine-lagoon complex of Cananéia, Brazil, using distance sampling. The survey covered 1339.91 km with 83 h 05 min in effort. A half-normal model with cosine adjustments was evaluated as the best fit to estimate an abundance of 193 individuals (95% CI 158–237) and a density of 2.55 ind km−2. The majority of sightings occurred in the Baía de Trapandé (48.72%), followed by the Mar de Cananéia (32.72%) and Mar de Cubatão (18.56%), the three areas surrounding the Ilha de Cananéia. The study confirmed the heterogeneous distribution of the estuary and found that the Mar de Cananéia and the Baía de Trapandé were more densely populated, with 2.76 ind km−2 (95% CI 1.93–3.96) and 2.76 ind km−2 (95% CI 2.07–3.66), respectively, while the Mar de Cubatão was less densely populated, with 1.59 ind km−2 (95% CI 1.04–2.44). The findings support previous research indicating a stable population over the last few decades. The Cananéia estuary is an ecologically diverse region located between protected areas under different categories of environmental protection and harbours a significant population of S. guianensis, providing essential resources for feeding and breeding. Protected areas have proven to be effective tools for preserving both marine and terrestrial environments. Despite the close proximity to humans and constant threats, the study underscores the importance of the area for the conservation of the species.

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20 years of research on the Guiana dolphin population of Sepetiba Bay, southeastern Brazil: What has changed?

Maciel,

Maricato,

Marqui

et al. 2023

Aquatic Conservation

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Despite the importance of coastal habitats for the provision of many ecosystem services, these areas are currently among the most impacted by human activities. Impacts on coastal ecosystems may affect many key species, such as the Guiana dolphin, which inhabits Sepetiba Bay in south‐eastern Brazil, a highly degraded environment owing to a human‐induced rapid environmental change. In this context, this study investigates the potential changes in the local Guiana dolphin behaviour, group structure, bioacoustics, site fidelity and habitat use over the past 20 years. For this, a historical database (1998–2007) was compared with current data on the local dolphin population (2017–2019). Between 2017 and 2019, the Guiana dolphins form significantly smaller groups (W = 3262.5, P > 0.001), spend more time foraging (61 vs. 10% in the past), emit whistles at a considerably lower rate (decreasing by 85.2%), have reduced site fidelity and now use a larger area. As Sepetiba Bay has been severely impacted by human activities in the recent past, with profound consequences for much of its biodiversity, the observed changes in dolphin behaviour are probably a consequence of habitat degradation and, in particular, of reduced prey availability. These findings have important implications for the management and conservation of the Guiana dolphin population of Sepetiba Bay. To break this human‐induced rapid environmental change, it will be essential to minimize the spatio‐temporal overlap of anthropogenic impacts, to avoid cumulative impacts. To mitigate anthropogenic impacts on the Guiana dolphins of Sepetiba Bay, it will be important to direct the following actions: (i) the regulation and control of anthropogenic noise; (ii) reduction and control of the release of chemical contaminants and organic effluents; (iii) more effective controls on vessel traffic within the areas used preferentially by the Guiana dolphin; and (iv) the implementation of measures to avoid overfishing and bycatch.

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Guiana Dolphin (Sotalia guianensis) in the southern Gulf of Venezuela: Seasonal distribution, group size, and habitat use

Cited by 7 publications

References 40 publications

Guiana Dolphin (Sotalia guianensis) in the Maracaibo Lake System, Venezuela: Conservation, Threats, and Population Overview

Guiana Dolphin (Sotalia guianensis) in the Maracaibo Lake System, Venezuela: Conservation, Threats, and Population Overview

Assessing Guiana dolphin abundance and density in the Southwestern Atlantic: insights from conservation areas

20 years of research on the Guiana dolphin population of Sepetiba Bay, southeastern Brazil: What has changed?

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