Genetic identity of <i>Sotalia</i> dolphins from the Orinoco River

Caballero, Susana; Trujillo, Fernando; Risco, Andrés del Risco and Alejandra Echeverri del A.; Herrera, Olga; Ferrer, Arnaldo

doi:10.1111/mms.12422

Cited by 7 publications

(4 citation statements)

References 24 publications

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“…The genus Sotalia, is represented by S. fluviatilis exclusive of continental environments of the Amazon basin (Da Silva 2002), and S. guianensis, documented from the mid-basin and the delta of the Orinoco river, the Maracaibo lake, and the Atlantic Coast in Central and South America from the south of Nicaragua to southern Brazil (Caballero et al 2007). Molecular data point to a recent divergence of continental populations of S. guianensis (600,000 years), from their coastal counterparts (Carvajal-Castro et al 2015;Caballero et al 2017). Furthermore, vicariate events among basins, associated with the presence of rapids and waterfalls, and the influence of climatic fluctuations, gave origin to three species within the genus Inia: I. geoffrensis (Da Silva 2009), with the subspecies: I. g. geoffrensis, distributed on the Amazon basin (Da Silva 2002), and I. g. humboldtiana, occurring on the Orinoco basin .…”

Section: Introductionmentioning

confidence: 99%

Population estimate and identification of major conservation threats for the river dolphin (Inia geoffrensis humboldtiana) at the Colombian Orinoquia

Mosquera-Guerra¹,

Trujillo²,

Aya-Cuero³

et al. 2020

Therya

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South American sub-continent, housed the largest diversity of river dolphins on the planet, here there are two species in the genus Sotalia and three species in the genus Inia. Tonina, present on the Orinoco basin, are exposed to many different anthropogenic threats, such as: the fragmentation and loss of aquatic ecosystems; acoustic contamination; risk of collision with boats; entanglement; deaths by retaliation, resulting from biological and operational interactions with artisanal and industrial fisheries; biomagnification of heavy metals such as mercury in the aquatic trophic web; capture of individuals for their usage as bait for the fishery of Calophysus macropterus, primarily on borderline localities between Colombia and Venezuela; and finally, the negative effects of climate change. We conducted a study to determine population sizes and anthropogenic threats affecting river dolphins populations during the beginning of high-water season, between November 2018 and February of 2019, along 1,402 km. We calculated the degradation index for streams of continental waters and density of the river dolphins. Water quality, habitat transformation, species exploitation, and the increment in number of human settlements were identified as the main conservation stressor in the analyzed area. We obtained density values by habitat type for different aquatic environments and population sizes for river dolphins and the value in the index of degradation, with a potential increment in value through time. River confluences were identified as priority areas for the conservation of the species. Water quality, habitat modification, and species exploitation were particularly intense. Our results highlight a potential transformation of the ideal conditions that allow for the establishment of the species, explaining its distribution with predicted values between 46.6 % and 70.1 % for the evaluated timeframe due to the effects of climate change on aquatic ecosystems. The Meta River, has the highest value for the index of freshwater ecosystems degradation followed by the Orinoco basin, water quality and species exploitation appear to be the major stressors for dolphins in these areas. Finally, river confluences were identified as conservation hot spots for dolphin populations. We point out on the importance of river dolphins as bioindicator, sentinel species, and one of the most susceptible to the negative effects of climate change.El subcontinente Suramericano, contiene la mayor diversidad de delfines de río del planeta, registrándose dos especies para el género Sotalia y tres especies para el género Inia. La Tonina, presente en la cuenca del Orinoco, está expuesta a diferentes amenazas de origen antrópico, como: la fragmentación y pérdida de los ecosistemas acuáticos; contaminación acústica; riesgo de colisión con embarcaciones; enmallamientos; muerte por retaliación, producto de interacciones biológicas y operacionales con pesquerías artesanales e industriales; biomagnificación de metales pesados como el mercurio en la red trófica a...

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Section: Introductionmentioning

confidence: 99%

Population estimate and identification of major conservation threats for the river dolphin (Inia geoffrensis humboldtiana) at the Colombian Orinoquia

Mosquera-Guerra¹,

Trujillo²,

Aya-Cuero³

et al. 2020

Therya

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“…del río Orinoco, Lago de Maracaibo y costas del Océano Atlántico en Centro y Suramérica). Los individuos de esta última especie, establecidos en la cuenca del Orinoco son simpátricos con I. g. humboldtiana y presentan 600 mil años de divergencia genética de las poblaciones costeras (Carvajal-Castro et al 2015, Caballero et al 2017. Estos procesos biogeográficos complejos ubican a las cuencas de los ríos Amazonas y Orinoco como las más diversas del planeta para este grupo cetáceos, registrando el mayor número de especies de delfines de río e incluso superando al continente asiático (Mosquera-Guerra et al 2015).…”

Section: Aspectos Poblacionales Y Biogeográficos De La Tonina O Delfíunclassified

Biodiversidad de la sierra de La Macarena, Meta, Colombia. Parte I. Ríos Guayabero medio, bajo Losada y bajo Duda

Morales-Betancourt¹,

Lasso²,

Mesa-S.³

et al. 2018

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“…They live exclusively in freshwater habitats in Asia and South America. The group includes the extinct baiji Lipotes vexillifer (Turvey et al 2007, the Yangtze finless porpoise Neophocaena asiaeorientalis asiaeorientalis, the Irrawaddy dolphin Orcaella brevirostris, the Ganges river dolphin Platanista gangetica, the Indus river dolphin P. minor (Braulik et al 2021), the tucuxi Sotalia fluviatilis (Caballero et al 2017), the Amazon river dolphin Inia geoffrensis geoffrensis and the Bolivian river dolphin I. g. boliviensis (Ruiz-Garcia et al 2008). Population numbers for the Asian species are in the low thousands (see Table 1 for details) and no accurate estimates are available for South America river cetaceans.…”

Section: Introductionmentioning

confidence: 99%

Challenges and priorities for river cetacean conservation

Campbell

Alfaro‐Shigueto

Aliaga-Rossel

et al. 2022

Endang. Species. Res.

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River cetaceans are particularly vulnerable to anthropogenic impacts due to their constrained ranges in freshwater systems of China, South Asia, and South America. We undertook an exhaustive review of 280 peer-reviewed papers and grey literature reports (1998-2020) to examine the current status of knowledge regarding these cetaceans and their conservation. We aimed to better understand the scale of threats they face, and to identify and propose priority future efforts to better conserve these species. We found that the species have been studied with varying frequency and that most of the research on threats has focused on habitat degradation and fragmentation (43%, mainly driven by dams and extractive activities such as sand mining and deforestation), and fishery interactions (39%, in the form of bycatch and direct take). These threats occur across all species, but more information is needed, primarily on quantifying the population impacts as a basis for designing mitigation measures. Other threats identified include pollution, vessel collisions, traditional use, and poorly managed tourism. Emerging methods such as environmental DNA and unmanned aerial vehicles are described for studying these species. Promising conservation interventions include cetacean-specific protected areas, natural ex situ protection, community-led conservation, and education programmes. However, transnational political will is required for a step change towards broad-scale protection in freshwater environments. In addition, we propose increasing capacity building, developing management plans, working closely with fishing communities, enhancing public awareness, expanding regional collaborations, and diversifying funding.

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Genetic identity of Sotalia dolphins from the Orinoco River

Cited by 7 publications

References 24 publications

Population estimate and identification of major conservation threats for the river dolphin (Inia geoffrensis humboldtiana) at the Colombian Orinoquia

Population estimate and identification of major conservation threats for the river dolphin (Inia geoffrensis humboldtiana) at the Colombian Orinoquia

Biodiversidad de la sierra de La Macarena, Meta, Colombia. Parte I. Ríos Guayabero medio, bajo Losada y bajo Duda

Challenges and priorities for river cetacean conservation

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