RESUMEN
Perfluorooctane sulfonate (PFOS) is a ubiquitous pollutant that elicits a wide range of toxic effects in exposed biota. Coastal zones in highly urbanized or industrial areas are particularly vulnerable to PFOS pollution. At present, information is lacking on biomarkers to assess PFOS effects on aquatic wildlife. This study investigated the efficacy of l-carnitine (or carnitine) and fatty acids as biomarkers of PFOS exposure in aquatic biota. The levels of PFOS, total and free carnitine, and 24 fatty acids (measured as fatty acid methyl esters or FAMEs) were measured in the liver, and muscle or blubber, of fish and dolphins sampled from Galveston Bay and the northern Gulf of Mexico (nGoM). Overall, bottlenose dolphins (Tursiops truncatus) had the highest hepatic PFOS levels. Galveston Bay fish, gafftopsail catfish (Bagre marinus), red drum (Sciaenops ocellatus), and spotted seatrout (Cynoscion nebulosus), had hepatic PFOS levels â¼8-13× higher than nGoM pelagic fish species, red snapper (Lutjanus campechanus) and yellowfin tuna (Thunnus albacares). The multivariate analysis of PFOS liver body-burdens and biomarkers found carnitine to be a more modal biomarker of PFOS exposure than FAMEs. Significant positive correlation of hepatic PFOS levels with total carnitine was evident for biota from Galveston Bay (fish only), and a significant correlation between PFOS and total and free carnitine was evident for biota from the nGoM (fish and dolphins). Given the essential role of carnitine in mediating fatty acid ß-oxidation, our results suggest carnitine to be a likely candidate biomarker of environmental PFOS exposure and indicative of potential dyslipidemia effects.
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Delfín Mular , Bagres , Animales , Golfo de México , Carnitina , Bahías , Delfín Mular/fisiología , Biota , Biomarcadores , Ácidos GrasosRESUMEN
Intraspecific whistle variation in dolphins has been explained in the context of geographical isolation, soundscape, and social structure. Whistles of two ecotypes of bottlenose dolphins from La Paz Bay, Gulf of California, were analyzed. Both ecotypes showed similar whistle contours. However, they could be identified by contour maximum frequency which was predominantly above 15 kHz for oceanic dolphins and below 15 kHz for coastal dolphins. The different whistle frequencies of the two ecotypes could result from differences in group size and acoustic characteristics of their respective habitats, suggesting potential future passive acoustic monitoring applications.
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Delfín Mular , Geraniaceae , Animales , Ecotipo , California , AcústicaRESUMEN
Animal vocalizations have nonlinear characteristics responsible for features such as subharmonics, frequency jumps, biphonation, and deterministic chaos. This study describes the whistle repertoire of a short-beaked common dolphin (Delphinus delphis) group at Brazilian coast and quantifies the nonlinear features of these whistles. Dolphins were recorded for a total of 67 min around Cabo Frio, Brazil. We identify 10 basic categories of whistle, with 75 different types, classified according to their contour shape. Most (45) of these 75 types had not been reported previously for the species. The duration of the whistles ranged from 0.04 to 3.67 s, with frequencies of 3.05-29.75 kHz. Overall, the whistle repertoire presented here has one of the widest frequency ranges and greatest level of frequency modulation recorded in any study of D. delphis. All the nonlinear features sought during the study were confirmed, with at least one feature occurring in 38.4% of the whistles. The frequency jump was the most common feature (29.75% of the whistles) and the nonlinear time series analyses confirmed the deterministic chaos in the chaotic-like segments. These results indicate that nonlinearities are a relevant characteristic of these whistles, and that are important in acoustic communication.
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Delfín Mular , Delfín Común , Delfines , Animales , Brasil , Espectrografía del Sonido , Vocalización AnimalRESUMEN
Passive acoustic monitoring (PAM) is an increasingly used technique to access the occurrence, distribution, and abundance of cetaceans that may be visually unavailable most of the time. The largest tailings dam failure disaster occurred on 5 November 2015, when the Fundão dam collapsed, releasing over 50 million cubic meters of tailings into the Doce River basin; 14 days later, the tailings plume reached the Atlantic Ocean. PAM was implemented in the concerned area and cetacean species were acoustically identified. Whistles and clicks of visual and acoustic matches were used to predict and classify exclusive acoustic records through random forest models. The identified species were Guiana, rough-toothed, and bottlenose dolphins. Additionally, the franciscana, the most threatened cetacean in the western South Atlantic Ocean, was also acoustically identified. The whistle classifier had 86.9% accuracy with final frequency, duration, and maximum frequency ranked as the most important parameters. The clicks classifier had 86.7% accuracy with peak frequency and 3 dB bandwidth as the most important parameters for classifying species. Considering the potential effect of the increase in turbidity on sound transmission, such as attenuation, the presented classifier should be continuously improved with novel data collected from long-term acoustic monitoring.
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Delfín Mular , Desastres , Animales , Brasil , Vocalización Animal , Acústica , RíosRESUMEN
In the presence of vessels, dolphins have been found to change their habitat, behavior, group composition and whistle repertoire. The modification of the whistle parameters is generally considered to be a response to the engine noise. Little is known about the impact of the physical presence of vessels on dolphin acoustics. Whistle parameters of the coastal and oceanic ecotypes of common bottlenose dolphins in La Paz Bay, Mexico, were measured after the approach of the research vessel and its engine shutdown. Recordings of 10 min were made immediately after turning off the engine. For analysis, these recordings were divided from minute 0 to minute 5, and from minute 5:01 to minute 10. The whistles of the oceanic ecotype showed higher maximum, minimum and peak frequency in the second time interval compared to the first one. The whistle rate decreased in the second time interval. The whistles of the coastal ecotype showed no difference between the two time intervals. The physical presence of the research vessel could have induced a change in the whistle parameters of the oceanic dolphins until habituation to the vessel disturbance. The oceanic ecotype could increase the whistle rate and decrease the whistle frequencies to maintain acoustic contact more frequently and for longer distances. The coastal ecotype, showing no significant changes in the whistle parameters, could be more habituated to the presence of vessels and display a higher tolerance.
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Delfín Mular , Delfín Común , Animales , Delfín Mular/fisiología , Vocalización Animal , Ecotipo , Ruido , AcústicaRESUMEN
Few studies have analyzed the indicators of oxidative stress in marine mammals following exposure to lipopolysaccharides (LPS); sex and maturity-related differences have not been explored. The objective of this study was to compare the indicators of oxidative stress following exposure to LPS for 24 and 48 h in isolated Pacific bottlenose dolphin (Tursiops truncatus; N = 12) leukocytes in relation to sex and maturity stage, using spectrophotometry. Following 48 h under experimental conditions (10 µg LPS mL-1), the leukocytes from males (n = 5) produced significantly more superoxide radical (O2â¢-; F (1, 8) = 13.965, p = 0.006) and displayed significantly greater activities of catalase (CAT; F (1, 8) = 9.465, p = 0.015) and glutathione S-transferase (GST; p = 0.028) compared to the leukocytes from females (n = 7). Following 48 h under experimental conditions, maturity-stage did not significantly influence the indicators of oxidative stress. Mature bottlenose dolphins (n = 7) had a significantly higher average daily dietary intake compared to immature bottlenose dolphins (n = 5; F (1, 10) = 5.825, p = 0.036). These results suggest that sex-related strategies for coping with a proinflammatory challenge may be present within the leukocytes from bottlenose dolphins, while potential maturity stage-related strategies require further investigation.
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Delfín Mular , Animales , Masculino , Femenino , Lipopolisacáridos , Leucocitos , Estrés OxidativoRESUMEN
Cetacean poxviruses (CePVs) cause 'tattoo' skin lesions in small and large cetaceans worldwide. Although the disease has been known for decades, genomic data for these poxviruses are very limited, with the exception of CePV-Tursiops aduncus, which was completely sequenced in 2020. Using a newly developed pan-pox real-time PCR system targeting a conserved nucleotide sequence located within the Monkeypox virus D6R gene, we rapidly detected the CePV genome in typical skin lesions collected from two Peruvian common bottlenose dolphins (Tursiops truncatus) by-caught off Peru in 1993. Phylogenetic analyses based on the sequencing of the DNA polymerase and DNA topoisomerase genes showed that the two viruses are very closely related to each other, although the dolphins they infected pertained to different ecotypes. The poxviruses described in this study belong to CePV-1, a heterogeneous clade that infects many species of dolphins (Delphinidae) and porpoises (Phocoenidae). Among this clade, the T. truncatus CePVs from Peru were more related to the viruses infecting Delphinidae than to those detected in Phocoenidae. This is the first time that CePVs were identified in free-ranging odontocetes from the Eastern Pacific, surprisingly in 30-year-old samples. These data further suggest a close and long-standing pathogen-host co-evolution, resulting in different lineages of CePVs.
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Delfín Mular , Chordopoxvirinae , Marsopas , Poxviridae , Animales , Delfín Mular/genética , Cetáceos , Chordopoxvirinae/genética , ADN-Topoisomerasas/genética , ADN Polimerasa Dirigida por ADN/genética , Perú/epidemiología , Filogenia , Marsopas/genética , Poxviridae/genética , Reacción en Cadena en Tiempo Real de la PolimerasaRESUMEN
Erysipelas is a zoonotic disease caused by Erysipelothrix rhusiopathiae. In cetaceans, this disease has two main clinical forms: a cutaneous one, grossly characterized by rhomboid lesions, and a septicemic and often fatal form. Erysipelas is considered an important cause of morbidity and mortality in captive cetaceans; however, information in free-ranging cetaceans is limited. An adult common bottlenose dolphin (Tursiops truncatus) was found dead and in advanced autolysis in Paraíba state, northeastern Brazil, on July 19th, 2020. Upon gross examination, 80% of the body surface presented disseminated rhomboid cutaneous lesions ranging from 4 to 6 cm-width, characterized by well-defined edges and occasional ulceration, consistent with erysipelas. Additionally, anthropic-made postmortem linear cuts and partial mechanical removal of the flank musculature were noted. Skin samples were collected for histopathologic and molecular analyses. Microscopically, it was possible to observe multifocal dermatitis with vasculitis. Erysipelothrix sp. was detected by PCR. Despite previous reports of human consumption of cetacean meat in northeastern Brazil, the observed marks and advanced carcass autolysis suggested that the animal was most likely used as bait for fishing instead of human intake. This case highlights the value of postmortem examination and PCR even in poorly preserved cadavers and contributes to the understanding of the epidemiology of cutaneous erysipelas in free-ranging cetaceans (first report in an odontocete from the Southern Hemisphere). Due to the zoonotic potential of certain Erysipelothrix species (i.e., E. rhusiopathiae), active public health policies are required to inform field professionals and the general public about the health threats associated with marine mammal manipulation and consumption.
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Delfín Mular , Erisipela , Erysipelothrix , Animales , Humanos , Erysipelothrix/genética , Reacción en Cadena de la Polimerasa , Brasil/epidemiologíaRESUMEN
Following the 2010 Deepwater Horizon disaster and subsequent unusual mortality event, adverse health impacts have been reported in bottlenose dolphins in Barataria Bay, LA including impaired stress response and reproductive, pulmonary, cardiac, and immune function. These conditions were primarily diagnosed through hands-on veterinary examinations and analysis of standard diagnostic panels. In human and veterinary medicine, gene expression profiling has been used to identify molecular mechanisms underlying toxic responses and disease states. Identification of molecular markers of exposure or disease may enable earlier detection of health effects or allow for health evaluation when the use of specialized methodologies is not feasible. To date this powerful tool has not been applied to augment the veterinary data collected concurrently during dolphin health assessments. This study examined transcriptomic profiles of blood from 76 dolphins sampled in health assessments during 2013-2018 in the waters near Barataria Bay, LA and Sarasota Bay, FL. Gene expression was analyzed in conjunction with the substantial suite of health data collected using principal component analysis, differential expression testing, over-representation analysis, and weighted gene co-expression network analysis. Broadly, transcript profiles of Barataria Bay dolphins indicated a shift in immune response, cytoskeletal alterations, and mitochondrial dysfunction, most pronounced in dolphins likely exposed to Deepwater Horizon oiling. While gene expression profiles in Barataria Bay dolphins were altered compared to Sarasota Bay for all years, profiles from 2013 exhibited the greatest alteration in gene expression. Differentially expressed transcripts included genes involved in immunity, inflammation, reproductive failure, and lung or cardiac dysfunction, all of which have been documented in dolphins from Barataria Bay following the Deepwater Horizon oil spill. The genes and pathways identified in this study may, with additional research and validation, prove useful as molecular markers of exposure or disease to assist wildlife veterinarians in evaluating the health of dolphins and other cetaceans.
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Delfín Mular , Delfín Común , Contaminación por Petróleo , Animales , Delfín Mular/genética , Delfín Mular/metabolismo , Perfilación de la Expresión Génica/veterinaria , Golfo de México , Humanos , Contaminación por Petróleo/efectos adversosRESUMEN
Marine mammals in subtropical coastal habitats are sentinels of the health of the ecosystem and offer important ecosystem services. They rely on prey that pursues feeding opportunities, while both avoid unfavorable conditions. In many cases, these predator-prey dynamics fluctuate seasonally and are regulated by lunar, tidal, and/or diel cycles (hour). However, these rhythmical patterns may vary under different seasonal conditions. Bottlenose dolphins (Tursiops truncatus) in the Ensenada de La Paz in Baja California Sur, Mexico, were detected acoustically over the course of an annual cycle on 21 separate occasions, covering 640 h from June 2017 to May 2019. The presence of bottlenose dolphins was examined using Generalized Additive Models (GAM) including variables that are related directly to their habitat (direct variables: hour, distance, depth) and to their prey (indirect variables: SST, moon phase and tides). Seasonal differences in the presence of bottlenose dolphins were influenced more by indirect variables (explained deviance: 34.8% vs. 37.7%). Hourly acoustic detections occurred less frequently when SST exceeded 27.4 °C (Aug-End of Nov.) and more frequently at moderate temperatures (22.7 °C to 26.3 °C) in May through July. Moreover, bottlenose dolphins were detected more frequently during waning and new moon phases, at the onset of flood and ebb tides, and during day (04:00 to 20:00). The seasonal differences in acoustic detections rates were highlighted by the global GAM and hierarchical clustering. The strong seasonal pattern indicated possible interactions with rhythmic pattern of bottlenose dolphins. Four candidate variables (SST, moon, tide, and hour) were tested for plausible interaction terms additional to their individual consideration, out of which only hour changed significantly between seasons. The patterns of presence likely increase feeding opportunities or may favor other behaviors such as socializing, resting, or nursing. These might prove responsible for the distinct occurrence and hourly patterns of bottlenose dolphins.
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Delfín Mular , Animales , Estaciones del Año , Ecosistema , México , AcústicaRESUMEN
Bottlenose dolphins (Tursiops truncatus) are found in coastal and estuarine ecosystems where they are in continuous contact with multiple abiotic and biotic stressors in the environment. Due to their role as predators, they can bioaccumulate contaminants and are considered sentinel organisms for monitoring the health of coastal marine ecosystems. The northern zonal coast of the Yucatan peninsula of Mexico has a high incidence of anthropogenic activities. The principal objectives of this study were two-fold: 1) to determine the presence of trace metals and their correlation with lipids in bottlenose dolphin blubber, and 2) to use a lipidomics approach to characterize their biological responses. Levels of trace elements (Al, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Cd, Pb) were analyzed using ICP-MS and lipids were measured using a targeted lipidomics approach with LC-MS/MS. Spearman correlation analysis was used to identify associations between lipids and trace elements. The influences of gender, stranding codes, presence of stomach content, growth stages and body length were also analyzed. Blubber lipid composition was dominated by triacylglycerols (TAG). Our results demonstrated the presence of heavy-metal elements such as Cd and As, which were correlated with different lipid species, mainly the ceramides and glycerophospholipids, respectively. Organisms with Cd showed lower concentrations of ceramides (CER, HCER and DCER), TAG and cholesteryl esters (CE). Trace elements Cr, Co, As and Cd increased proportionately with body length. This study provides a novel insight of lipidomic characterization and correlations with trace elements in the bottlenose dolphin which might contribute to having a better understanding of the physiological functions and the risks that anthropogenic activities can bring to sentinel organisms from coastal regions.
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Delfín Mular , Oligoelementos , Contaminantes Químicos del Agua , Animales , Cadmio/análisis , Ceramidas , Cromatografía Liquida , Ecosistema , Monitoreo del Ambiente , Lipidómica , Lípidos , México , Espectrometría de Masas en Tándem , Oligoelementos/análisis , Contaminantes Químicos del Agua/análisisRESUMEN
Marine species from the Gulf of Mexico often have higher mercury (Hg) concentrations than conspecifics in the Atlantic Ocean. Spatial differences in Hg sources, environmental conditions, and microbial communities influence both Hg methylation rates and the bioavailability of Hg to organisms at the base of the food web. Mercury bioaccumulates within organisms and biomagnifies in marine food webs, and therefore reaches the greatest concentrations in long-lived marine carnivores, such as dolphins. In this study, we explored whether differences in trophic position and foraging habitat among bottlenose dolphins (Tursiops truncatus) from the northern Gulf of Mexico (nGoM) contributed to the observed variation in skin total Hg (THg) concentrations. Using the δ13C and δ34S values in dolphin skin, we assigned deceased stranded dolphins from Florida (FL; n = 29) and Louisiana (LA; n = 72) to habitats (estuarine, barrier island, and coastal) east and west of the Mississippi River Delta (MRD). We estimated the mean trophic position of dolphins from each habitat using δ15N values from stranded dolphin skin and tissues of primary consumers taken from the literature following a Bayesian framework. Finally, we compared trophic positions and THg concentrations among dolphins from each habitat, accounting for sex and body length. Estimated marginal mean THg concentrations (µg/g dry weight) were greatest in dolphins assigned to the coastal habitat and estuarine habitats east of the MRD (range: 2.59-4.81), and lowest in dolphins assigned to estuarine and barrier island habitats west of the MRD (range: 0.675-0.993). On average, dolphins from habitats with greater THg concentrations also had higher estimated trophic positions, except for coastal dolphins. Our results suggest that differences in trophic positions and foraging habitats contribute to spatial variability in skin THg concentrations among nGoM bottlenose dolphins, however, the relative influence of these factors on THg concentrations are not easily partitioned.
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Delfín Mular , Mercurio , Contaminantes Químicos del Agua , Animales , Teorema de Bayes , Monitoreo del Ambiente , Golfo de México , Mercurio/análisis , Contaminantes Químicos del Agua/análisisRESUMEN
The Deepwater Horizon (DWH) oil spill profoundly impacted the health of bottlenose dolphins (Tursiops truncatus) in Barataria Bay, LA (BB). To comprehensively assess the cardiac health of dolphins living within the DWH oil spill footprint, techniques for in-water cardiac evaluation were refined with dolphins cared for by the U.S. Navy Marine Mammal Program in 2018 and applied to free-ranging bottlenose dolphins in BB (n = 34) and Sarasota Bay, Florida (SB) (n = 19), a non-oiled reference population. Cardiac auscultation detected systolic murmurs in the majority of dolphins from both sites (88% BB, 89% SB) and echocardiography showed most of the murmurs were innocent flow murmurs attributed to elevated blood flow velocity [1]. Telemetric six-lead electrocardiography detected arrhythmias in BB dolphins (43%) and SB dolphins (31%), all of which were considered low to moderate risk for adverse cardiac events. Echocardiography showed BB dolphins had thinner left ventricular walls, with significant differences in intraventricular septum thickness at the end of diastole (p = 0.002), and left ventricular posterior wall thickness at the end of diastole (p = 0.033). BB dolphins also had smaller left atrial size (p = 0.004), higher prevalence of tricuspid valve prolapse (p = 0.003), higher prevalence of tricuspid valve thickening (p = 0.033), and higher prevalence of aortic valve thickening (p = 0.008). Two dolphins in BB were diagnosed with pulmonary arterial hypertension based on Doppler echocardiography-derived estimates and supporting echocardiographic findings. Histopathology of dolphins who stranded within the DWH oil spill footprint showed a significantly higher prevalence of myocardial fibrosis (p = 0.003), regardless of age, compared to dolphins outside the oil spill footprint. In conclusion, there were substantial cardiac abnormalities identified in BB dolphins which may be related to DWH oil exposure, however, future work is needed to rule out other hypotheses and further elucidate the connection between oil exposure, pulmonary disease, and the observed cardiac abnormalities.
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Delfín Mular , Lesiones Cardíacas/veterinaria , Contaminación por Petróleo/efectos adversos , Animales , Delfín Mular/anomalías , Delfín Mular/fisiología , Ecocardiografía/veterinaria , Electrocardiografía/veterinaria , Fibrosis/diagnóstico por imagen , Fibrosis/veterinaria , Corazón/diagnóstico por imagen , Corazón/fisiología , Lesiones Cardíacas/diagnóstico por imagen , Hipertensión/veterinariaRESUMEN
The vocal repertoire of the pantropical spotted dolphin (Stenella attenuata) is poorly documented, with no published information about acoustic signals from South Atlantic Ocean populations. We conducted passive acoustic monitoring and recording of S. attenuata population in the Santos Basin, Brazil, using a towed hydrophone array during line-transects surveys. Our monitoring yielded whistle samples derived from eight groups of S. attenuata, from which we selected 155 whistles for further analysis. Approximately 48% of the whistles presented ultrasonic frequency values, with maximum frequencies up to 31.1 kHz. Across the sample, the number of steps ranged from 0 to 20 and inflection points ranged from 0 to 8. On average, end frequencies were higher than start frequencies, and whistles generally presented wide frequency ranges, with an average of 11.3 kHz. The most predominant whistle contour category was "ascending-descending." Our study provides new information regarding the acoustic repertoire of this poorly documented species and will aid efforts for using acoustics to identify and monitor cetaceans in this region.
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Delfín Mular , Stenella , Animales , Océano Atlántico , Brasil , Espectrografía del Sonido , Vocalización AnimalRESUMEN
Health assessments were conducted on bottlenose dolphins in Barataria Bay, Louisiana, USA, during 2011 to 2018, to assess potential health effects following the Deepwater Horizon oil spill, compared to the unoiled Sarasota Bay, Florida, USA, reference dolphin population. We previously reported significant increases in T-lymphocyte proliferation, as well as lower T helper 1 (Th1) cytokines, higher Th2 cytokine IL-4, and lower T regulatory (Treg) cytokine IL-10 in Barataria Bay in 2011 compared to Sarasota Bay, consistent with Deepwater Horizon oil exposure. Although values between 2013 and 2016 were more similar to those observed in Sarasota Bay, T-cell proliferation was again elevated and cytokine balance tilted toward Th2 in Barataria Bay during 2017-2018. In 2018, Barataria Bay dolphins had significantly more circulating Treg cells than Sarasota Bay dolphins. Mice experimentally exposed to oil also had significantly increased T-lymphocyte proliferation and circulating Treg cell number, including effects in their unexposed progeny. In vitro stimulation resulted in greater Th2 responsiveness in Barataria Bay compared to Sarasota Bay dolphins, and in vitro oil exposure of Sarasota Bay dolphin cells also resulted in enhanced Th2 responsiveness. Evidence points to Treg cells as a potential target for the immunomodulatory effects of oil exposure. The immunological trends observed in Barataria Bay appeared exaggerated in dolphins born after the spill, suggesting the possibility of continued oil exposure or multigenerational health consequences of exposure to oil, as observed in mice. Environ Toxicol Chem 2021;40:1308-1321. © 2021 SETAC.
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Delfín Mular , Contaminación por Petróleo , Animales , Florida , Golfo de México , Louisiana , RatonesRESUMEN
Tursiops truncatus gephyreus is only found in the inshore waters of the Southwestern Atlantic Ocean. They are organized in small socially, structured groups, which lead to low genetic variability and high anthropogenic threats. Currently, the information about their reproductive biology and management is still insufficient. Thus, this study aims to present novel information recorded for 20 years regarding reproductive parameters in a small population of captive T. t. gephyreus. Three of the animals involved were found stranded in La Plata River estuary and, the other two were born at the oceanarium. Thirteen semen evaluations showed high-quality semen with a low percentage of sperm abnormalities. Twelve pregnancies and parturitions were observed. There was a clear calving seasonality during austral spring and summer. The duration of phase-2 of labor was approximately 80 min, being the caudal presentation the most frequent. The average inter-birth interval (IBI) was about 33 months. This is the first report that closely monitored parturition, IBI, and seminal evaluation in this species. Information gathered during this program will allow the development of adequate conservation plans for free-ranging populations.
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Crianza de Animales Domésticos , Delfín Mular/fisiología , Cruzamiento , Parto/fisiología , Animales , Femenino , Masculino , Embarazo , Preñez , Análisis de Semen/veterinariaRESUMEN
We report for the first time the infection of dolphins with Ascocotyle longa found in the intestines of three different species, Sotalia guianensis, Steno bredanensis, and Tursiops truncatus gephyreus, which were found washed ashore along the southeastern and southern Brazilian coast. The worms were identified based on morphological and molecular data using the 28S rDNA gene and the COI gene. Specimens of A. longa from the pinniped Otaria flavescens were also analyzed. As the first isolation of A. longa from cetaceans, the present study increases the distribution area and range of definitive hosts of this trematode, and provides new molecular data to complement the phylogeny of the group in future studies, thus contributing to the scientific knowledge of this potentially zoonotic parasite.
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Delfín Mular/parasitología , Heterophyidae , Infecciones por Trematodos/veterinaria , Animales , Océano Atlántico , Brasil , Complejo IV de Transporte de Electrones/genética , Heterophyidae/clasificación , Heterophyidae/genética , Heterophyidae/aislamiento & purificación , Intestinos/parasitología , ARN Ribosómico 28S/genética , Infecciones por Trematodos/parasitologíaRESUMEN
The common bottlenose dolphin, Tursiops truncatus, is widely distributed. However, information about its ecology and behavior in Brazilian waters is scarce especially about the 'offshore' ecotype, an Evolutionarily Significant Unit in the Southwest Atlantic. We report for the first time the occurrence, behavior and habitat use of bottlenose dolphins Tursiops truncatus truncatus, in two Marine Protected Areas (MPA) in Cabo Frio coast, Brazil. There were fifteen sightings of different groups throughout the year. An overall of 429 individuals were photo-identified. 90.7% dolphins did not present a degree of residence, 1.4% dolphins were considered with high residency to the area, 5.8% medium and 2.1% low. Our habitat use map indicated dolphins were more common off ~10km from Cabo Frio municipality and between depths around 20-70m. Bottlenose dolphins on Cabo Frio coast were more frequently observed performing travelling, followed by foraging and socio-sexual behavior. Group sizes varied from three to 120 individuals. Larger groups were observed when travelling and foraging. Despite the existence of two local Marine Protected Areas, the fast human development in Cabo Frio may threaten this important area for bottlenose dolphins in terms of food resources and shelter from predators.
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Delfín Mular , Migración Animal , Animales , Brasil , EcosistemaRESUMEN
Melioidosis is an emerging infectious disease of humans and animals caused by the bacterium Burkholderia pseudomallei and endemic in tropical regions, principally Southeast Asia and northern Australia. In September 2017, after Hurricane Maria impacted the Dolphin Discovery facility in the Federation of St. Kitts and Nevis, a juvenile male bottlenose dolphin (Tursiops truncatus) died within 96 hr of presenting with acute anorexia, lethargy, and respiratory distress. Histopathology demonstrated necrohemorrhagic bronchopneumonia, necrotizing hepatitis, splenitis, and lymphadenitis, with intralesional Gram-negative bacilli. B. pseudomallei was confirmed by bacteriological culture and DNA sequencing. This case emphasizes the challenges of melioidosis diagnosis, the importance of awareness for both early detection and efficacious treatment, and recognition in tropical regions where it has been either not reported or underreported. To the authors' knowledge, this is the first case of cetacean melioidosis in the Caribbean Islands, an often severe and fatal disease with increasing prevalence on the American continent.
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Delfín Mular , Burkholderia pseudomallei/aislamiento & purificación , Melioidosis/veterinaria , Animales , Animales de Zoológico , Tormentas Ciclónicas , Diagnóstico Diferencial , Masculino , Melioidosis/diagnóstico , Melioidosis/microbiología , San Kitts y NevisRESUMEN
The bottlenose dolphin, genus Tursiops, is cosmopolitan occurring in tropical and temperate regions, with morphological variation between and within different oceans. Since the genus' taxonomy has been under discussion for a long time, this work aimed at analyzing the cranial variability of T. truncatus from different regions of the world. Geometric Morphometrics analyses were performed in 201 skulls of adult specimens, on dorsal, ventral, and lateral views, from the Eastern North Pacific, Eastern North Atlantic, Eastern South Atlantic, and Western South Atlantic oceans. The results indicate differences between individuals that inhabit the Atlantic and Pacific oceans. Within the Atlantic Ocean, there is an evident longitudinal differentiation of specimens from the eastern and western regions. A latitudinal separation was also observed, considering specimens from the North and South Atlantic Ocean. In the Western South Atlantic statistical differences were found between two morphological groups, identified as T. gephyreus (sensu Lahille, 1908) and T. truncatus, and the cross-validation presented 98% as minimum confidence for correct classification of these two groups. The present study provides strong morphological support to consider these two lineages as separate species.