Search

Summary tables for all the details of nesting seasons for Sea Turtles (Leatherbacks and hawkbills) during years 2009 until 2018 in the Gulf of Paria, Venezuela. Dates, precipitation, timing, nest numbers, and clutch size.

Los parásitos coccidiales afectan varias especies de reptiles a nivel mundial y son responsables de la muerte de cientos de ejemplares cautivos y silvestres en diferentes regiones del planeta. Entre los años 2011 y 2013, cuatro de 108 tortugas verdes (3,70 %) rescatadas por Grupo de Trabajo en Tortugas Marinas del Golfo de Venezuela, a través de la “Red de Aviso Oportuno (RAO)”, presentaron diferentes estadios evolutivos morfológicamente semejantes a Caryospora sp. en heces o tejidos. Los animales infectados fueron juveniles de tortuga verde capturados por pesquerías artesanales. Se les practicaron exámenes físicos, coprológicos y hematológicos. En tres ejemplares se observaron abundantes ooquistes de morfología compatible con Caryospora cheloniae (K001, K002, SB001). Uno de los animales presentó en capa blanca, leucocitos que contenían estructuras parecidas a esporozoitos de Caryospora sp, indicativo de coccidiosis sistémica. Dos de las tortugas se encontraron asintomáticas (K003, SB001), y dos se presentaron clínicamente enfermas con signos neurológicos como movimientos involuntarios de cabeza y aletas, espasmos musculares, movimientos natatorios circulares y depresión. Dos animales murieron (K001, K002), en ambos se encontraron diversos estadios de un organismo coccidial consistente con Caryospora sp. en intestino, además una enteritis necrótica moderada. Este constituye el primer reporte de coccidiosis en tortugas marinas en Venezuela y en el Caribe sur.

Conflicts among and between local, national, regional and international stakeholders involved in marine turtle conservation are increasing. Often, they arise because of different socio-economic backgrounds of the people or groups involved. Here, we identified and assessed the conservation-based conflicts occurring in 24 of the 39 Caribbean countries, including their frequency, level of severity, number of stakeholders' groups involved, the degree to which they hinder conservation goals, and potential solutions. Using a cross-sectional social survey, we evaluated the presence and details of conservation conflicts provided by 72 respondents. The respondents included conservation-based project leaders, researchers, people involved in policy-based decision-making, conservation volunteers (community-based conservation groups), and species experts with experience working on marine turtle conservation programs in the Caribbean. The respondents identified 136 conflicts, and we grouped them into 16 different categories. The most commonly mentioned causes of conflicts were: 1) the ‘lack of enforcement by local authorities to support conservation-based legislation or programs’ (18%); 2) ‘legal consumption of turtles by one sector of community clashing the conservation aspirations of other sectors of community (14%); and 3) ’variable enforcement of legislation to limit/prohibit use across range states of the species (10%). From our data it is also apparent that illicit activities in the region are also likely to impact the future success of conservation or monitoring based projects and programs. Overall, an exhaustive review was carried out, and the potential solutions were gathered. Due to the level of severity (physical violence) that some conflicts have reached, achieving solutions will be challenging without mediation, mutual cooperation around shared values, and adaptive management arrangements. Achieving this will require combinations of bottom up and top down collaborative governance approaches.

Leatherback turtle (Dermochelys coriacea) is highly impacted by fisheries’ bycatch worldwide. This study updates and estimates the leatherback turtle stranding records from 2001 to 2014 in the Gulf of Venezuela. Eighty-six stranded leatherback turtles were documented in the coast of the Gulf of Venezuela. Immature leatherback turtles were the most affected (85.1%) and the highest number of strandings were recorded during the dry season (55.8%). Our findings represent the minimum estimate of stranding events for the Gulf of Venezuela, especially considering the current lack of fisheries regulations. This is the latest update for the leatherback turtle strandings in the Gulf of Venezuela and could help to create new management solutions in the area aiming to minimize the impact on leatherback turtle populations in the Caribbean.

Although sea turtles have received substantial focus worldwide, research on the immature life stages is still relatively limited. The latter is of particular importance, given that a large proportion of sea turtle populations comprises immature individuals. We set out to identify knowledge gaps and identify the main barriers hindering research in this field. We analyzed the perceptions of sea turtle experts through an online survey which gathered their opinions on the current state of affairs on immature sea turtle research, including species and regions in need of further study, priority research questions, and barriers that have interfered with the advancement of research. Our gap analysis indicates that studies on immature leatherback Dermochelys coriacea and hawksbill Eretmochelys imbricata turtles are lacking, as are studies on all species based in the Indian, South Pacific, and South Atlantic Oceans. Experts also perceived that studies in population ecology, namely on survivorship and demography, and habitat use/behavior, are needed to advance the state of knowledge on immature sea turtles. Our survey findings indicate the need for more interdisciplinary research, collaborative efforts (e.g. data-sharing, joint field activities), and improved communication among researchers, funding bodies, stakeholders, and decision-makers. Fil: Wildermann, Natalie E.. Florida State University; Estados Unidos Fil: Gredzens, Christian. Florida State University; Estados Unidos Fil: Avens, Larisa. National Ocean And Atmospheric Administration; Estados Unidos Fil: Barrios Garrido, Héctor A.. Universidad del Zulia; Venezuela. Florida State University; Estados Unidos Fil: Bell, Ian. Aquatic Species Program. Conservation And Biodiversity Operations Branch; Australia Fil: Blumenthal, Janice. Cayman Islands Department Of Environment; Islas Caimán Fil: Bolten, Alan B.. University of Florida; Estados Unidos Fil: McNeill, Joanne Braun. National Ocean And Atmospheric Administration; Estados Unidos Fil: Casale, Paolo. Università degli Studi di Pisa; Italia Fil: Di Domenico, Maikon. Universidade Federal do Paraná; Brasil Fil: Domit, Camila. Universidade Federal do Paraná; Brasil Fil: Epperly, Sheryan P.. National Ocean And Atmospheric Administration; Estados Unidos Fil: Godfrey, Matthew H.. North Carolina Wildlife Resources Commission; Estados Unidos. University of North Carolina; Estados Unidos. University of Duke; Estados Unidos Fil: Godley, Brendan J.. University of Exeter; Reino Unido Fil: González Carman, Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Subsede Instituto Nacional de Investigación y Desarrollo Pesquero; Argentina Fil: Hamann, Mark. James Cook University; Australia Fil: Hart, Kristen M.. United States Geological Survey; Estados Unidos Fil: Ishihara, Takashi. Sea Turtle Association of Japan; Japón. Suma Aqualife Park; Japón Fil: Mansfield, Kate L.. University Of Central Florida; Estados Unidos Fil: Metz, Tasha L.. No especifica; Fil: Miller, Jeffrey D.. No especifica; Fil: Pilcher, Nicolas J.. Marine Research Foundation; Malasia Fil: Read, Mark A.. Great Barrier Reef Marine Park Authority; Australia Fil: Sasso, Christopher. National Ocean And Atmospheric Administration; Estados Unidos Fil: Seminoff, Jeffrey A.. National Ocean And Atmospheric Administration; Estados Unidos Fil: Seney, Erin E.. University Of Central Florida; Estados Unidos Fil: Williard, Amanda Southwood. University of North Carolina; Estados Unidos Fil: Tomás, Jesús. Universidad de Valencia; España Fil: Vélez Rubio, Gabriela M.. Universidad de la República; Uruguay. Karumbé Ngo; Uruguay Fil: Ware, Matthew. Florida State University; Estados Unidos Fil: Jessica L. Williams. Tartarugas para o Amanhã; Mozambique Fil: Wyneken, Jeanette. Florida Atlantic University; Estados Unidos Fil: Fuentes, Mariana M. P. B. Florida State University; Estados Unidos

The longnose stingray ( Dasyatis guttata ) is a target species in the artisanal fisheries of the southern Gulf of Venezuela. Despite its economic importance, nowadays, studies about its status are lacking. During six continuous months (18 working days in total), we followed the artisanal fishery activities from Zapara Island, and evaluated morphometric characteristics, sex ratio, and the capture per unit effort (CPUE/ind/1000 hooks) of D. guttata . Biological sampling included: disc widths (AD), body mass total (PT), and sex. Using statistical analysis we assessed: a) the length-weight relationships by sex, b) monthly body condition, using the Fulton Index (K), and c) the CPUE. We evaluated 210 individuals of D. guttata . The mean values of our results were: AD = 64.14 ± 13.18cm (range 32-95 cm); PT = 8.36 ± 4.87 kg (range 0.80- 24.50 kg). The sexual proportion was (2.26♀: 1♂) ( X 2 = 31.716, P < 0.05); hence we presume a spatial segregation occurred between females and males in the studied area. Length-weight relationship was statistically significant (P < 0.0001), and also varied according to the sex ♀: PT(kg) = [(0.00027)×(AD(cm) 2.46 )]; ♂: PT(kg) = [(0.00035)×(AD(cm) 2.34 )]. The K value showed differences between sexes during November and December. We obtained a CPUE of 4.88 individuals/1000 hooks. We compared our findings with previous research carried out in the southern Caribbean. Further research about this species in the area is recommended.

Tortuguero is a small Caribbean village of Costa Rica, where sea turtles have always played a central role in the culture and economy. Historically, Tortuguero based its economy on the exploitation of natural resources, including marine turtles. However, thanks to long term conservation efforts, policy modifications and a change in the mindset of the community, this village is now globally recognized as an example of how marine turtles can be used to generate significant revenue in a non-extractive way, through ecotourism. Nevertheless, poaching of nests and egg trade still occurs in the area. This study identifies the perceptions and attitudes of the local community towards the consumption and trade of sea turtle eggs and its impact on conservation. From October to December 2017, a total of 187 questionnaires were distributed to the community of Tortuguero, and 17 semi-structured interviews were conducted with local key informants. Our results show that sea turtle egg consumption still persists within the community, and it is perceived as a frequent practice (Questionnaire Respondents (QR); 62.2%, n = 51/Interview Respondents (IR); 58.8%, n = 10). There is awareness among villagers about the negative effects of sea turtle egg consumption mainly on the economy (QR; 76.7%, n = 89), tourism (QR; 88.4%, n = 107) and conservation (QR; 87%, n = 107), and the practice is negatively regarded (QR; 77%, n = 107/IR; 76.5%, n = 13). Nevertheless, consumption continues as a traditional practice (QR; 26.7%, n = 28/IR; 41.2%, n = 7), facilitated by the ease to obtain eggs (QR; 19.4%, n = 20/IR; 76.5 n = 13) and the persisting belief of their aphrodisiac properties (QR 18.6%; n = 19/IR 23.5%; n = 4). Despite this and the perceived lack of enforcement, interviewees stated that most consumers do not risk taking the eggs and they buy them from local poachers (IR; 88.2%, n = 15), who are usually associated with substance abuse problems. In addition, most interviewees (94.1%, n = 16) affirmed that consumption in the community has decreased over the last 10 years, and that the majority of eggs extracted from Tortuguero are traded with nearby Caribbean communities (76.5%, n = 13). The destination of the eggs seems to depend on the area from which they were taken and prices range widely depending on the seller and the trade area. Overall, this study provides an improved understanding of the local perception of egg consumption and trade dynamics. Additionally, it provides insights into the challenges of tackling this issue in Costa Rica's Caribbean coast. We hope that our conclusions will contribute to the improvement of current conservation and management strategies in the region.

The impact of artisanal fisheries on marine turtle populations is still understudied in the southern Caribbean. In the Venezuelan Guajira Peninsula, artisanal fishing of marine turtles by the indigenous Wayuu people has occurred for generations. Nevertheless, understanding the issues regarding turtle take is challenging. Surveys and semi-structured interviews were carried out at eight landing sites located in three different zones in Kazuzain village, Middle Guajira. Carapaces or plastrons were recorded to estimate take level, and measured to determine life stage. Minimum take was 167 marine turtles over 53 weeks, or 3.15 turtles/week on average (estimated 163.8/yr). Most records encountered were from green turtles (n=154; 92.2%), and the majority of these were immature (n=76; 89.4%). Key-informants reported that marine turtles were not the target catch. However, most interviewees affirmed that take of marine turtles in Kazuzain is not only for traditional purposes, but also to meet economic shortfalls. They also stated that trade of marine turtles has increased over the last ten years due to the Venezuelan economic crisis. This is the first assessment of marine turtle take in this village and fills an information gap that can aid resource managers to mitigate the impacts of take, and develop potential conservation solutions for marine turtle aggregations and the people that depend on them.

Human societies are closely linked to their ecological environments. Natural ecosystems and wildlife populations are often in better condition in countries with healthy, educated and economically prosperous populations compared to countries with lower health and literacy conditions, and depressed economies. In the latter countries, these socio-economic factors can compromise government's capacity to manage their natural resources. Thus, the conservation capacity of a government is likely to play key role in the protection of threatened species, such as marine turtles. This paper aims: (1) to evaluate the conservation capacity and enforcement within the 58 Regional Management Units (RMUs) of the seven species of marine turtles throughout the world, and (2) to develop a proxy that predicts the conservation status of RMUs. We developed a Conservation and Enforcement Capacity index (CECi) by integrating the following indices: (a) the economic level and, (b) the Human Development Index (HDI) of each country, plus (c) the risks and threats in the RMUs. We used the conservation status of 15 RMUs recently assessed by the International Union for Conservation of Nature - IUCN to predict the conservation status of the 43 RMUs without updated IUCN categorisation. CECi values ranged from 0 to 1, where lower values represent a better capacity for implementation of conservation initiatives. We found that using our multi-index model, we predicted the status of 33 of 58 RMUs, 57% of which may be of threatened conservation status due to their high CECi values. This study highlighted how socio-economic aspects may impact conservation of endangered species.

Marine turtles are challenging species to protect because they occur over large geographic scales. Tagging individual turtles at nesting beaches and foraging areas, and the resulting mark-recapture data sets have gradually enabled us to understand marine turtle migratory behaviour and dispersal. Within the Caribbean region, several turtle tagging projects have led to longer-term evaluations and assessments of connectivity. Thus, marine turtle mark-recapture data is important for developing conservation strategies at regional-scale. In this study, we analyse turtle tagging data from the Gulf of Venezuela to determine regional (Caribbean and Atlantic geographic level) and local (within the Gulf of Venezuela) links. To achieve this, we retrieved, compiled, and analysed multiple databases with records of marine turtles that were tagged and then recaptured in the Gulf of Venezuela. Sixty-six tag return records were evaluated, 43 from animals initially tagged outside of the Gulf of Venezuela and then recaptured inside, plus 23 records retrieved from turtles that were tagged and recaptured within the Gulf of Venezuela. We found evidence of connectivity between 12 different locations where initial tagging events occurred, eight from other feeding areas and four from nesting beaches. We described four different movement patterns for 23 turtles tagged and re-captured within the Gulf of Venezuela. Most of the recapture records we obtained occurred after the turtles were known, or presumed, to have been killed by local fishers. Hence, knowing patterns of dispersal and connectivity are crucial to improving local and regional conservation and threat mitigation.

Fisheries, either directed or via bycatch, are a major cause of decline in global populations of marine turtles. Although artisanal fisheries are often seen as lower-impact than industrial fisheries, they may be among the most serious threats to green turtles. Between 2005 and 2008, to better understand the impacts of such fisheries in the High Extraction Zone of the Gulf of Venezuela (HEZ-GV), an important feeding habitat for green turtles, we interviewed fishers, observed fishing activities directly, and counted, measured, and marked discarded turtle carapaces at fishing ports and traditional markets. From these, we estimated that at least 3,402 ± 247 turtles/year were extracted with artisanal nets, suggesting that the HEZ-GV artisanal turtle fishery may have been among the most active in the Caribbean at the time, with a CPUE of 0.04 turtles/km-net*hour ±0.014. However, capture was not selective, confirming prior anecdotal information suggesting that this fishery supplies mainly subsistence and not commercial use. Harvested turtles consisted mainly of juveniles (64%, CCLmin = 55.7 cm ± SE 0.9), and subadults (35%, CCLmin = 78.9 cm ± 0.6 cm), with very few adults (1%, CCLmin = 98 cm ± 0.6 cm). Our findings highlight the need for continued monitoring of the artisanal turtle fishery in the HEZ-GV, particularly given the possibility of increased reliance on aquatic bushmeat sources in Venezuela's present socio-economic crisis. More broadly, they also indicate that scientifically based catch guidelines for marine turtles may be just as important in artisanal as in commercial fisheries, to ensure sustainability and mitigate harvest impacts.

Small cetaceans, such as the Guiana dolphin (Sotalia guianensis), do not migrate long distances to forage but use rather small areas subject to food source variations. Information on their distribution, behaviour, habitat use, and estimated population density play an important role in the identification of critical areas and regulating human activities within. Here we examine the seasonal variations, group size, and distribution of Guiana dolphin in the southern Gulf of Venezuela, to identify their critical habitats and thus aid mitigation planning. We used boat-based surveys with a follow-group protocol where observers monitor groups of animals for 30 min, from a distance of 20 to 30 m, gathering the following data: date, time observed, GPS position, estimated number of individuals, presence of calves, behavioural observations (when possible); and environmental parameters (sea-surface temperature, water transparency, salinity, sea state [Beaufort], and cloud cover). We found that Guiana dolphins did not use the studied area (6.33 km2) homogeneously but rather aggregated in north of Zapara Island’s retaining wall. The highest density of dolphins was between 301 and 573 individuals within 4.22 km2 approximately off north of Zapara Island, and the lowest (1 - 150 individuals) at the entrance of the main navigation channel. The group size was considerably larger in the wet season (mean ± SD = 6.4 ± 1.9 individuals, range = 1 to 80) than the dry season (2.2 ± 2.7 individuals, range = 1 to 27). The number of sightings differed among seasons (dry/wet), there were more sightings in the wet season (1.3414 ± 0.4389 groups, range = 1 to 5) than dry season (1.1233 ± 0.7418 groups, range = 1 to 5). Our data suggest this population might be highly adapted to local conditions and prey movements, and use the areas intensely year around, particularly during the wet season.

Background Marine turtles play an important role in the culture and economy of numerous coastal communities around the world. However, the legal framework that regulates the consumptive use of these reptiles varies among countries.For example, the consumption of these reptiles has been regarded as common in several rural areas of Venezuela, especially in the eastern coast of the Guajira Peninsula. Methods To assess the scale and cultural component of this use, we interviewed 35 residents from the southwestern coast of the Gulf of Venezuela (Venezuelan part of the Guajira Peninsula), using a combination of in-depth and semi-structured interviews. We carried out a field and detailed market-based observations on the Guajira Peninsula to detect the sale and use of marine turtle products. We focused on three main categories of use; the type of product, routes of trade, and the price of products. Results All of the marine turtle species reported from the Gulf of Venezuela were used, and the prices of products varied among their type, species of origin, and the distance from the capture area to a marketplace. We obtained evidence connecting Wayuú Indigenous people's traditions and beliefs with marine turtle use, and also they are used as traditional products such as medicine, and as an economic resource to sustain their communities. Conclusion It is probable that trade of marine turtle products is placing pressure on populations in the Gulf of Venezuela. We recommend the implementation of an inter-institutional conservation-portfolio be developed for the Peninsula to evaluate actions related to this concern.

Marine turtles are considered by people of several cultures to be a gift from God. This belief often leads to the use of these reptiles in the traditional and belief systems among aboriginal peoples. Certainly this is the case among Wayuu people, who are an indigenous group settled between Venezuela and Colombia, in the Guajira Peninsula. To assess the value of marine turtles to Wayuu ancestral people, especially as a medicinal resource, we carried out a comprehensive open-ended question-based survey of traditional healers and caretakers (locally known as Piaches and Outsus) from 4 Wayuu communities in the Venezuelan portion of the Guajira Peninsula. We documented customary practices where marine turtles' body parts are used as a key element of the remedies. Eleven marine turtle body parts were identified by respondents as remedies used by Wayuu people, with 7 different ways to administer them (drink, worn, powder, among others). Four of the 5 species of marine turtles present in Venezuelan waters were identified as being used in the traditional pharmacopoeia of Wayuu people; their traditional names are included on this article. Some considerations about the Wayuu's cosmovision, customs, traditions, and belief systems are included here. Our results are important in the context of likely future evaluation of the current Venezuelan legal framework to consider inclusion of traditional use of marine turtles in Venezuela. Abstract [Spanish] Las tortugas marinas son consideradas por diversas culturas como un regalo proveniente de Dios. Es en esta creencia en la que usualmente se basan las tradiciones y costumbres de numerosas comunidades indigenas que utilizan a estos reptiles a nivel global. Ciertamente, este es el caso de los indigenas Wayuu, grupo el cual se encuentra asentado entre Colombia y Venezuela, en la Peninsula de la Guajira. Se realizo una valoracion ancestral de las tortugas marinas para los indigenas Wayuu, con especial enfasis en los usos medicinales, se llevaron a cabo una evaluacion comprensiva y exhaustiva, la cual incluyo entrevistas y encuestas con preguntas abiertas, a pobladores Wayuu con amplio conocimiento sobre las practicas medicinales tradicionales (conocidos localmente como Piaches y Outsus) en comunidades localizadas en la porcion venezolana de la Peninsula de la Guajira (territorio ancestral Wayuu). Se documentaron las practicas y costumbres en las que diversas partes del cuerpo de la tortuga marina juegan un papel primordial en la creacion y aplicacion de estos remedios tradicionales. Los entrevistados identificaron hasta once diferentes partes del cuerpo de la tortuga marina que son utilizados en la elaboracion de remedios, asi como siete diferentes formas de administracion de la medicina (tomada, untada, granulada, entre otros). Cuatro de las cinco especies de tortugas marinas presentes en las aguas territoriales venezolanas fueron identificadas como parte importante de la farmacopea tradicional de los indigenas Wayuu, en este articulo se incluyen los nombres tradicionales en Wayuunaikii de estos reptiles. Asi mismo, en la presente investigacion se mencionan algunas consideraciones sobre la cosmovision, costumbres, tradiciones y creencias Wayuu. Estos resultados son importantes en el contexto de una posible futura revision del marco ambiental legal venezolano para considerar una posible inclusion de estos usos tradicionales de tortugas marinas en Venezuela.

We report the crab species Callinectes sapidus (Decapoda: Portunidae) as a diet item for adult olive ridleys (Lepidochelys olivacea). This is the first-ever report of this species as part of the diet for olive ridley turtles and helps further our understanding of the foraging ecology of this species in coastal marine habitats.

Dolphins of the genus Sotalia are found along the Caribbean and Atlantic coasts of Central and South America and in the Amazon River and most of its tributaries. At present, the taxonomy of these dolphins remains unresolved. Although five species were described in the late 1800s, only one species is recognized currently (Sotalia fluviatilis) with two ecotypes or subspecies, the coastal subspecies (Sotalia fluviatilis guianensis) and the riverine subspecies (Sotalia fluviatilis fluviatilis). Recent morphometric analyses, as well as mitochondrial DNA analysis, suggested recognition of each subspecies as separate species. Here we review the history of the classification of this genus and present new genetic evidence from ten nuclear and three mitochondrial genes supporting the elevation of each subspecies to the species level under the Genealogical/Lineage Concordance Species Concept and the criterion of irreversible divergence. We also review additional evidence for this taxonomic revision from previously published and unpublished genetic, morphological, and ecological studies. We propose the common name “costero” for the coastal species, Sotalia guianensis (Van Beneden 1864), and accept the previously proposed “tucuxi” dolphin, Sotalia fluviatilis (Gervais, 1853), for the riverine species.

Las asociaciones entre aves marinas y mamíferos marinos es un evento común en todos los mares y océanos del mundo. Muchos autores han denominado estas asociaciones como relaciones comensalistas, oportunistas o parasitarias, según el efecto que dicha interacción resulte sobre una o ambas especies relacionadas. Con la finalidad de describir la existencia de agrupaciones entre Sotalia guianensis y aves marinas en la porción sur del Golfo de Venezuela, desde junio 2011 a junio 2012 se realizaron observaciones en plataformas móviles de grupos de este cetáceo y aves marinas, utilizando el protocolo “group-follow” bajo la metodología de “Ad libitum sampling”. Todos los avistamientos fueron georreferenciados, realizándose anotaciones de la ocurrencia o no-asociación con aves marinas, de igual forma, se registró la especie y el número de aves presentes al momento de la interacción. Se realizaron 721 avistamientos, de los cuales en 197 eventos se registró asociación entre aves marinas y Sotalia guianensis. Las especies de aves marinas residentes que presentaron mayor frecuencia en eventos de asociación con S. guianensis fueron: Fregata magnificens (49%; n=98), Phalacrocorax brasilianus (29,5%; n=59) y Pelecanus occidentalis (22,5%; n=45); siendo Thalasseus maxima (71%; n=142) la única especie migratoria. Durante las observaciones realizadas en el período de muestreo se notó la presencia de una especie de golondrina (Riparia riparia) en un solo evento de agrupación con Sotalia guianensis. Dichas asociaciones aves-delfines, sólo fueron observadas cuando notables congregaciones de peces fueron registrados, donde el o los grupos de delfines realizaban alguna actividad con grandes movimientos de agua, lo que pudiese permitir a las aves realizar un menor gasto energético en la ubicación y la captura de la presa.

Here we consider the phylogeography and population structure of the South American coastal and riverine dolphins, Sotalia guianensis and Sotalia fluviatilis, based on samples (n = 76) collected across more than 9000km of the species distribution. Phylogenetic reconstruction of 31 distinct haplotypes based on a combined analysis of two mitochondrial gene fragments (1052bp) revealed clear genetic differences between riverine and coastal individuals consistent with species-level ranking. Within the coastal species, a spatial analysis of molecular variance of the control region sequences showed significant regional population differentiation (FST = 0.4; FST = 0.6; P

Genes of the major histocompatibility complex (MHC) play a key role in the initiation of immune response in jawed vertebrates. Variation at MHC loci can be used as an indicator of the genetic ‘health’ of natural populations and offer insight into potential susceptibility to epizootics. Here we present the first characterization of the sequence variation at two MHC class II loci (DQA and DQB) in the neotropical coastal ( Sotalia guianensis ) and riverine ( Sotalia fluviatilis ) dolphins, using cloning and direct sequencing of amplified genomic DNA. Four DQA and four DQB alleles were identified in 33 and 32 Sotalia samples, respectively, and high nucleotide diversity among these alleles was detected, similar to the findings described for other cetacean species. Positive selection was evidenced by an excess of d n /d s at the Peptide-Binding-Region of the DQB of Sotalia . The presence of common alleles at both loci in S. fluviatilis and S. guianensis are consistent with trans-species mode of evolution in the MHC. In contrast to observed low levels of mtDNA diversity at the population level, there was an apparent lack of reduction of DQA and DQB allelic variation in the Brazilian Coast population unit. This suggests either present or past balancing selection acting to maintain MHC variation in this population unit.

The evolutionary relationships among members of the cetacean family Delphinidae, the dolphins, pilot whales and killer whales, are still not well understood. The genus Sotalia (coastal and riverine South American dolphins) is currently considered a member of the Stenoninae subfamily, along with the genera Steno (rough toothed dolphin) and Sousa (humpbacked dolphin). In recent years, a revision of this classification was proposed based on phylogenetic analysis of the mitochondrial gene cytochrome b, wherein Sousa was included in the Delphininae subfamily, keeping only Steno and Sotalia as members of the Stenoninae subfamily. Here we investigate the phylogenetic placement of Sotalia using two mitochondrial genes, six autosomal introns and four Y chromosome introns, providing a total of 5,196 base pairs (bp) for each taxon in the combined dataset. Sequences from these genomic regions were obtained for 17 delphinid species, including at least one species from each of five or six currently recognized subfamilies plus five odontocete outgroup species. Maximum Parsimony, Maximum Likelihood and Bayesian phylogenetic analysis of independent (each fragment) and combined datasets (mtDNA, nuDNA or mtDNA+nuDNA) showed that Sotalia and Sousa fall within a clade containing other members of Delphininae, exclusive of Steno. Sousa was resolved as the sister taxon to Sotalia according to analysis of the nuDNA dataset but not analysis of the mtDNA or combined mtDNA+nuDNA datasets. Based on the results from our multi-locus analysis, we offer several novel changes to the classification of Delphinidae, some of which are supported by previous morphological and molecular studies.