Long-term site fidelity and residency patterns of bottlenose dolphins (Tursiops  truncatus) in the Tramandaí Estuary, southern Brazil

Giacomo, Amanda Baron Di; Ott, Paulo Henrique

doi:10.5597/00224

Cited by 19 publications

(21 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…On the other hand, remarkably low levels of genetic diversity for the coastal ecotype likely reflects small population sizes of possibly a few hundred individuals (Fruet, Flores, et al., ; Fruet, Zappes, et al., ). Mark‐recapture data from long‐term studies of coastal populations along the SWA indicate critical small population sizes (populations not exceeding 90 individuals) and high site fidelity of individuals (e.g., Daura‐Jorge, Ingram, & Simões‐Lopes, ; Fruet, Daura‐Jorge, Möller, Genoves, & Secchi, ; Giacomo & Ott, ; Laporta, Fruet, et al., ; Vermeulen & Cammareri, ).…”

Section: Discussionmentioning

confidence: 99%

Genetic divergence between two phenotypically distinct bottlenose dolphin ecotypes suggests separate evolutionary trajectories

Fruet¹,

Secchi

Tullio³

et al. 2017

Ecology and Evolution

View full text Add to dashboard Cite

Due to their worldwide distribution and occupancy of different types of environments, bottlenose dolphins display considerable morphological variation. Despite limited understanding about the taxonomic identity of such forms and connectivity among them at global scale, coastal (or inshore) and offshore (or oceanic) ecotypes have been widely recognized in several ocean regions. In the Southwest Atlantic Ocean (SWA), however, there are scarce records of bottlenose dolphins differing in external morphology according to habitat preferences that resemble the coastal‐offshore pattern observed elsewhere. The main aim of this study was to analyze the genetic variability, and test for population structure between coastal (n = 127) and offshore (n = 45) bottlenose dolphins sampled in the SWA to assess whether their external morphological distinction is consistent with genetic differentiation. We used a combination of mtDNA control region sequences and microsatellite genotypes to infer population structure and levels of genetic diversity. Our results from both molecular marker types were congruent and revealed strong levels of structuring (microsatellites F ST = 0.385, p < .001; mtDNA F ST = 0.183, p < .001; ΦST = 0.385, p < .001) and much lower genetic diversity in the coastal than the offshore ecotype, supporting patterns found in previous studies elsewhere. Despite the opportunity for gene flow in potential “contact zones”, we found minimal current and historical connectivity between ecotypes, suggesting they are following discrete evolutionary trajectories. Based on our molecular findings, which seem to be consistent with morphological differentiations recently described for bottlenose dolphins in our study area, we recommend recognizing the offshore bottlenose dolphin ecotype as an additional Evolutionarily Significant Unit (ESU) in the SWA. Implications of these results for the conservation of bottlenose dolphins in SWA are also discussed.

show abstract

Section: Discussionmentioning

confidence: 99%

Genetic divergence between two phenotypically distinct bottlenose dolphin ecotypes suggests separate evolutionary trajectories

Fruet¹,

Secchi

Tullio³

et al. 2017

Ecology and Evolution

View full text Add to dashboard Cite

show abstract

“…Aunque los bufeos costeros pueden vivir en comunidades semicerradas relativamente pequeñas, hay pocos antecedentes de comunidades tan reducidas como la de la puntilla de Santa Elena. Uno de estos casos ocurre en el estuario Tramandaí, al sur de Brasil, donde una comunidad residente de nueve animales ha sido monitoreada por años aparentemente sin cambios en el número total de animales (Di Giacomo & Ott, 2016). Comunidades de bufeos costeros tan pequeñas son difíciles de estudiarlas, probablemente son remanentes de comunidades de delfines que en algún momento fueron más grandes y han sufrido reducciones considerables y podrían estar en proceso de extinción.…”

Section: Discussionunclassified

“…Así mismo, se ha encontrado en otros sitios una vinculación estrecha entre la presión de pesca y el abandono de áreas tradicionales de los delfines (e.g. Morteo et al, 2012a;Di Giacomo & Ott, 2016). La alta tasa de cicatrices en el cuerpo de los delfines de Santa Elena reportada recientemente muestra que las colisiones y las redes pesqueras han afectado más a estos animales que en otros sitios del país (Félix et al, 2018a).…”

Section: Discussionunclassified

“…Esta forma de organización social ocurre en diferentes partes del mundo donde han sido estudiados como en Estados Unidos (Wells et al, 1987), Brasil (Simoes-Lopes & Fabian, 1999) o Australia (Möller, Wiszniewski, Allen, & Beheregaray, 2007). La organización social, distribución y patrones de movimiento están regulados por factores biológicos intrínsecos como el sexo y la edad (Félix, 1997;Fury, Rucksthul, & Harrison, 2013;Morteo, Rocha-Olivares, & Abarca-Arenas, 2014), factores ecológicos como la distribución y disponibilidad de sus presas, presión por depredación y competencia intra e interespecífica, así como condiciones ambientales cambiantes debido a la variabilidad estacional, al ciclo de mareas, entre otros, y en algunos casos en función de usos antrópicos de la zona costera que pueden llegar a modificar sus patrones espacio-temporales de distribución (e.g., Lusseau, 2004;Morteo, Rocha-Olivares, Arceo-Briseño, & Abarca-Arenas, 2012a;Di Giacomo & Ott, 2016). Al igual que otros delfines costeros alrededor del mundo, los delfines nariz de botella costeros están amenazados por actividades humanas como la pesca, el tráfico marítimo y la degradación del hábitat por la contaminación en sus diferentes formas (Parsons & Jefferson, 2000;Reeves, Smith, Crespo, & Notarbartolo di Sciara, 2003;Reeves, McClellan, & Werner, 2013;Van Waerebeek et al, 2007;Azevedo et al, 2017).…”

unclassified

See 1 more Smart Citation

Distribución espacial, estructura social y amenazas de conservación de una pequeña comunidad de delfines nariz de botella, Tursiops trunca (Odontoceti: Delphinidae) en Ecuador

Félix

Zavala²,

Centeno³

2019

RBT

View full text Add to dashboard Cite

Socio-ecological and conservation aspects of a small community of bottlenose dolphins Tursiops truncatus (Odontoceti: Delphinidae) in Santa Elena, Ecuador. A resident community of bottlenose dolphins (Tursiops truncatus) has been studied irregularly between 2005 and 2018 around the tip of the Santa Elena Peninsula, Ecuador (2°11'S, 81°0.7'W). Opportunistic sightings and systematic surveys from the beach and at sea from a boat were carried out along 40 km of coast, accounting for 917.2 km of tracking by car from land and 707.4 km of boat tracking by sea. Average group size was 5.31 dolphins/group (SD= 1.97, range 1-10), with no significant changes throughout the study period. From land, however, the group size was underestimated 32% on the average. This small dolphin community currently has only nine individuals, including six adults, one immature and two calves. The relative abundance ranged between 0.03 dolphins/km in the northwestern part and 0.32 dolphins/km in the south, where dolphins concentrate their activities, possibly because human activities are less intense. Dolphins were generally distributed in the first 200 m from the shore, reaching up to 1,200 in the northern shallower part and where port and tourist activities concentrate. The dolphins’ speed was significantly higher when they were followed from a boat at close range (5.87 km/h) than when they were monitored from the beach (2.9 km/h) (P < 0.01), which suggests that boat tracking had an effect on dolphin´s movements. Pairwise cluster analysis showed that animals from this community show high rates of association among each other (average 0.67, range 0.01-1.0), indicating this is highly cohesive population unit. Dolphins also showed high level of residence (average occurrence index = 0.62). During the study, two main threats were identified, a gillnet fishery in the southwestern part and an intense fishing boat traffic in the northwestern. This coastal bottlenose dolphin community is the smallest of this species ever reported in the Gulf of Guayaquil, probably is a remnant of a larger population that would be in process of extinction. Most of the study area is currently part of a coastal-marine protected area created in 2008, which offers an opportunity for the recovery and conservation of this dolphin community. Given the fragility of this population unit, we recommend to environment authorities addressing potential threats by eliminating gillnets, implementing an exclusion zone for fishing gear and fishing boat traffic of 1 km width from the shore and limit the speed of any type of vessel to 10 knots within the reserve.

show abstract

“…Group sizes seemed stable in populations studied over long-term periods (i.e. more than one decade in Laguna: Simões-Lopes, 1991;Daura-Jorge et al, 2013;and Tramandaí River: Simões-Lopes, 1991;Hoffmann et al, 2008;Giacomo and Ott, 2016 this volume; and more than two decades in the PLE: Möller, 1993;Dalla Rosa, 1999;Mattos et al, 2007;Fruet et al, 2011;2015).…”

Section: Behaviormentioning

confidence: 99%

Report of the Working Group on the Behavioral Ecology of bottlenose dolphins in the Southwest Atlantic Ocean

Domit

Laporta²,

Zappes

et al. 2017

Lat. Am. J. Aquat. Mamm.

View full text Add to dashboard Cite

In this report, we present a compilation of the behavioral patterns of bottlenose dolphins and social structure throughout the Southwest Atlantic Ocean. We have compiled and summarized available data concerning: (i) behavioral activities (states and events), (ii) social structures (group size and composition), (iii) acoustic behavior and (iv) intra and interspecific interactions of bottlenose dolphin populations throughout the SWAO, from northern Brazil to southern Argentina. Lack of systematic and standardized methodologies for data collection precludes robust data analyses in respect of bottlenose dolphin behavior. Available information suggests that the studied populations presented weak intra-population associations and that coastal individuals tend to form smaller groups than their oceanic counterparts. Bottlenose dolphins from SWAO produce stylized whistles in which the acoustic parameters are similar to published ranges around the world and some results indicate significant local inter-population variation in the acoustic parameters of the whistles. Data of intra and interspecific interactions of bottlenose dolphins in the SWAO are scarce and therefore do not fully allow a comprehensive analysis of the situational contexts.

show abstract

Long-term site fidelity and residency patterns of bottlenose dolphins (Tursiops truncatus) in the Tramandaí Estuary, southern Brazil

Cited by 19 publications

References 19 publications

Genetic divergence between two phenotypically distinct bottlenose dolphin ecotypes suggests separate evolutionary trajectories

Genetic divergence between two phenotypically distinct bottlenose dolphin ecotypes suggests separate evolutionary trajectories

Distribución espacial, estructura social y amenazas de conservación de una pequeña comunidad de delfines nariz de botella, Tursiops trunca (Odontoceti: Delphinidae) en Ecuador

Report of the Working Group on the Behavioral Ecology of bottlenose dolphins in the Southwest Atlantic Ocean

Contact Info

Product

Resources

About