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1.
PLoS One ; 17(8): e0272345, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36001538

RESUMO

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.


Assuntos
Golfinho Nariz-de-Garrafa , Golfinhos Comuns , Poluição por Petróleo , Animais , Golfinho Nariz-de-Garrafa/genética , Golfinho Nariz-de-Garrafa/metabolismo , Perfilação da Expressão Gênica/veterinária , Golfo do México , Humanos , Poluição por Petróleo/efeitos adversos
2.
BMC Ecol Evol ; 22(1): 88, 2022 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-35818031

RESUMO

BACKGROUND: High levels of standing genomic variation in wide-ranging marine species may enhance prospects for their long-term persistence. Patterns of connectivity and adaptation in such species are often thought to be influenced by spatial factors, environmental heterogeneity, and oceanographic and geomorphological features. Population-level studies that analytically integrate genome-wide data with environmental information (i.e., seascape genomics) have the potential to inform the spatial distribution of adaptive diversity in wide-ranging marine species, such as many marine mammals. We assessed genotype-environment associations (GEAs) in 214 common dolphins (Delphinus delphis) along > 3000 km of the southern coast of Australia. RESULTS: We identified 747 candidate adaptive SNPs out of a filtered panel of 17,327 SNPs, and five putatively locally-adapted populations with high levels of standing genomic variation were disclosed along environmentally heterogeneous coasts. Current velocity, sea surface temperature, salinity, and primary productivity were the key environmental variables associated with genomic variation. These environmental variables are in turn related to three main oceanographic phenomena that are likely affecting the dispersal of common dolphins: (1) regional oceanographic circulation, (2) localised and seasonal upwellings, and (3) seasonal on-shelf circulation in protected coastal habitats. Signals of selection at exonic gene regions suggest that adaptive divergence is related to important metabolic traits. CONCLUSION: To the best of our knowledge, this represents the first seascape genomics study for common dolphins (genus Delphinus). Information from the associations between populations and their environment can assist population management in forecasting the adaptive capacity of common dolphins to climate change and other anthropogenic impacts.


Assuntos
Golfinhos Comuns , Animais , Genética Populacional , Genômica , Genótipo , Oceanografia
3.
Curr Biol ; 32(15): 3436-3442.e2, 2022 08 08.
Artigo em Inglês | MEDLINE | ID: mdl-35882234

RESUMO

Episodic memory involves the conscious recollection of personally experienced events, which has often been argued to be a uniquely human ability.1-5 However, evidence for conscious episodic recall in humans is centered around language-based reports. With no agreed upon non-linguistic behavioral makers of consciousness,6 episodic-like memory7 therefore represents the behavioral characteristics of human episodic memory, in the absence of evidence for subjective experience during recall. Here, we provide compelling evidence for episodic-like memory in common bottlenose dolphins (Tursiops truncatus), based on the incidental encoding and unexpected question paradigm.8 This methodology aims to capture the incidental encoding characteristic of human episodic memory, in that when we recall an experience, we remember information that was trivial at the time of encoding, but was encoded automatically.9 We show that dolphins are able to use incidentally encoded spatial ("where") and social ("who") information to solve an unexpected memory task, using only a single test trial per test type, which ensured that the dolphins did not have the opportunity to semantically learn "rules" to pass the test. All participating dolphins made correct choices in both the "where" and "who" tests. These results suggest that dolphins are capable of encoding, recalling, and accessing incidental information within remembered events, which is an ability indicative of episodic memory in humans. We argue that the complex socio-ecological background of dolphins may have selected for the ability to recall both spatial and social information in an episodic-like manner.


Assuntos
Golfinho Nariz-de-Garrafa , Golfinhos Comuns , Memória Episódica , Animais , Estado de Consciência , Humanos , Rememoração Mental
4.
Mar Pollut Bull ; 180: 113745, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35653906

RESUMO

Marine mammals can serve as an indicator of ecosystem health, and are likely exposed to significant amounts of microplastics (MPs). In this study we estimated the MP uptake of two odontocetes, the short-beaked common dolphin (Delphinus delphis) and the common bottlenose dolphin (Tursiops truncatus), in the Mediterranean Sea and the Northeast Atlantic. These two species are expected to primarily ingest MPs through trophic transfer. To this end, data was collected on their diet, which was subsequently linked to MP occurrence and abundance in prey families. We estimated that D. delphis ingests 76 MPs/day in the Northeast Atlantic and 164 MPs/day in the Mediterranean, and T. truncatus ingests 36 MPs/day in the Northeast Atlantic and 179 MPs/day in the Mediterranean. This study provides important new predictions on MP exposure in two odontocetes, and opens up new research opportunities on the effect of this exposure on the health of organisms.


Assuntos
Golfinho Nariz-de-Garrafa , Golfinhos Comuns , Animais , Oceano Atlântico , Ecossistema , Mar Mediterrâneo , Microplásticos , Plásticos
5.
J Morphol ; 283(4): 446-461, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35066941

RESUMO

In all mammals, the superior olivary complex (SOC) comprises a group of auditory brainstem nuclei that are important for sound localization. Its principal nuclei, the lateral superior olive (LSO) and the medial superior olive (MSO) process interaural time and intensity differences, which are the main cues for sound localization in the horizontal plane. Toothed whales (odontocetes) rely heavily on hearing and echolocation for foraging, orientation, and communication and localize sound with great acuity. The investigation of the SOC in odontocetes provides insight into adaptations to underwater hearing and echolocation. However, quantitative anatomical data for odontocetes are currently lacking. We quantified the volume, total neuron number, and neuron density of the LSO of six common dolphins (Delphinus delphis) using the Cavalieri principle and the unbiased stereology optical fractionator. Our results show that the LSO in D. delphis has a volume of 150 + (SD = 27) mm3 , which is on average 69 (SEM = 19) times larger than the LSO in human, or 37 (SEM = 11) times larger than the human LSO and MSO combined. The LSO of D. delphis contains 20,876 ± (SD = 3300) neurons. In comparison, data reported for the human brainstem indicate the LSO has only about » that number but about the same number for the LSO and MSO combined (21,100). LSO neurons range from 21 to 25 µm (minor axis) and from 44 to 61 µm (major axis) in transverse sections. The LSO neuron packing density is 1080 ± (SD = 204) neurons/mm3 , roughly half of the LSO neuron density in human. SMI-32-immunohistochemistry was used to visualize projection neurons in the LSO and revealed the presence of principal, marginal, and multipolar neurons in transverse sections. The distinct morphology of the LSO likely reflects the common dolphin's superb sensitivity to ultra-high frequencies and ability to detect and analyze sounds and their location as part of its underwater spatial localization and echolocation tasks.


Assuntos
Golfinhos Comuns , Ecolocação , Complexo Olivar Superior , Animais , Cetáceos , Ecolocação/fisiologia , Núcleo Olivar/anatomia & histologia , Núcleo Olivar/fisiologia
6.
Mar Pollut Bull ; 174: 113194, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34902768

RESUMO

Human noise can be harmful to sound-centric marine mammals. Significant research has focused on characterizing behavioral responses of protected cetacean species to navy mid-frequency active sonar (MFAS). Controlled exposure experiments (CEE) using animal-borne tags have proved valuable, but smaller dolphins are not amenable to tagging and groups of interacting individuals are more relevant behavioral units for these social species. To fill key data gaps on group responses of social delphinids that are exposed to navy MFAS in large numbers, we describe novel approaches for the coordinated collection and integrated analysis of multiple remotely-sensed datasets during CEEs. This involves real-time coordination of a sonar source, shore-based group tracking, aerial photogrammetry to measure fine-scale movements and passive acoustics to quantify vocal activity. Using an example CEE involving long-beaked common dolphins (Delphinus delphis bairdii), we demonstrate how resultant quantitative metrics can be used to estimate behavioral changes and noise exposure-response relationships.


Assuntos
Golfinhos Comuns , Golfinhos , Acústica , Animais , Ruído , Tecnologia de Sensoriamento Remoto , Som
7.
Mar Pollut Bull ; 173(Pt B): 113084, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34775153

RESUMO

Here we provide a first assessment of microplastics (MPs) in stomach contents of 15 common dolphins (Delphinus delphis) from both single and mass stranding events along the New Zealand coast between 2019 and 2020. MPs were observed in all examined individuals, with an average of 7.8 pieces per stomach. Most MPs were fragments (77%, n = 90) as opposed to fibres (23%, n = 27), with translucent/clear (46%) the most prevalent colour. Fourier transform infrared (FTIR) spectroscopy revealed polyethylene terephthalate (65%) as the most predominant polymer in fibres, whereas polypropylene (31%) and acrylonitrile butadiene styrene (20%) were more frequently recorded as fragments. Mean fragment and fibre size was 584 µm and 1567 µm, respectively. No correlation between total number of MPs and biological parameters (total body length, age, sexual maturity, axillary girth, or blubber thickness) was observed, with similar levels of MPs observed between each of the mass stranding events. Considering MPs are being increasingly linked to a wide range of deleterious effects across taxa, these findings in a typically pelagic marine sentinel species warrants further investigation.


Assuntos
Golfinhos Comuns , Poluentes Químicos da Água , Animais , Monitoramento Ambiental , Análise de Fourier , Microplásticos , Nova Zelândia , Plásticos , Espectroscopia de Infravermelho com Transformada de Fourier , Poluentes Químicos da Água/análise
8.
Mar Pollut Bull ; 173(Pt A): 112896, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34601248

RESUMO

Profiles of 33 PFAS analytes and 12 essential and non-essential trace elements were measured in livers of stranded common dolphins (Delphinus delphis) from New Zealand. PFAS concentrations reported were largely comparable to those measured in other marine mammal species globally and composed mostly of long-chain compounds including perfluorooctanesulfonic acid (PFOS), perfluorododecanoic acid (PFDoDA), perfluorotridecanoic acid (PFTrDA) and perfluorooctanesulfonamide (FOSA). PFAS profiles did not vary significantly by location, body condition, or life history. Notably, significant positive correlations were observed within respective PFAS and trace elements. However, only negative correlations were evident between these two contaminant types, suggesting different exposure and metabolic pathways. Age-associated concentrations were found for PFTrDA and four trace elements, i.e. silver, mercury, cadmium, selenium, indicating differences in the bioaccumulation biomagnification mechanisms. Overall, our results contribute to global understanding of accumulation of PFAS by offering first insights of PFAS exposure in cetaceans living within South Pacific Australasian waters.


Assuntos
Ácidos Alcanossulfônicos , Golfinhos Comuns , Fluorcarbonetos , Oligoelementos , Animais , Monitoramento Ambiental , Fluorcarbonetos/análise , Nova Zelândia , Oligoelementos/análise
9.
Toxins (Basel) ; 13(10)2021 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-34678990

RESUMO

Dolphins are well-regarded sentinels for toxin exposure and can bioaccumulate a cyanotoxin called ß-N-methylamino-l-alanine (BMAA) that has been linked to human neurodegenerative disease. The same dolphins also possessed hallmarks of Alzheimer's disease (AD), suggesting a possible association between toxin exposure and neuropathology. However, the mechanisms of neurodegeneration in dolphins and the impact cyanotoxins have on these processes are unknown. Here, we evaluate BMAA exposure by investigating transcription signatures using PCR for dolphin genes homologous to those implicated in AD and related dementias: APP, PSEN1, PSEN2, MAPT, GRN, TARDBP, and C9orf72. Immunohistochemistry and Sevier Münger silver staining were used to validate neuropathology. Methylmercury (MeHg), a synergistic neurotoxicant with BMAA, was also measured using PT-GC-AFS. We report that dolphins have up to a three-fold increase in gene transcription related to Aß+ plaques, neurofibrillary tangles, neuritic plaques, and TDP-43+ intracytoplasmic inclusions. The upregulation of gene transcription in our dolphin cohort paralleled increasing BMAA concentration. In addition, dolphins with BMAA exposures equivalent to those reported in AD patients displayed up to a 14-fold increase in AD-type neuropathology. MeHg was detected (0.16-0.41 µg/g) and toxicity associated with exposure was also observed in the brain. These results demonstrate that dolphins develop neuropathology associated with AD and exposure to BMAA and MeHg may augment these processes.


Assuntos
Diamino Aminoácidos/toxicidade , Golfinhos Comuns , Agonistas de Aminoácidos Excitatórios/toxicidade , Compostos de Metilmercúrio/toxicidade , Doenças Neurodegenerativas/veterinária , Poluentes Químicos da Água/toxicidade , Animais , Feminino , Masculino , Massachusetts , Doenças Neurodegenerativas/induzido quimicamente , Doenças Neurodegenerativas/patologia
10.
Philos Trans R Soc Lond B Biol Sci ; 376(1836): 20210046, 2021 10 25.
Artigo em Inglês | MEDLINE | ID: mdl-34482716

RESUMO

The most flexible communication systems are those of open-ended vocal learners that can acquire new signals throughout their lifetimes. While acoustic signals carry information in general voice features that affect all of an individual's vocalizations, vocal learners can also introduce novel call types to their repertoires. Delphinids are known for using such learned call types in individual recognition, but their role in other contexts is less clear. We investigated the whistles of two closely related, sympatric common dolphin species, Delphinus delphis and Delphinus bairdii, to evaluate species differences in whistle contours. Acoustic recordings of single-species groups were obtained from the Southern California Bight. We used an unsupervised neural network to categorize whistles and compared the resulting whistle types between species. Of the whistle types recorded in more than one encounter, 169 were shared between species and 60 were species-specific (32 D. delphis types, 28 D. bairdii types). Delphinus delphis used 15 whistle types with an oscillatory frequency contour while only one such type was found in D. bairdii. Given the role of vocal learning in delphinid vocalizations, we argue that these differences in whistle production are probably culturally driven and could help facilitate species recognition between Delphinus species. This article is part of the theme issue 'Vocal learning in animals and humans'.


Assuntos
Golfinhos Comuns/fisiologia , Aprendizagem , Reconhecimento Psicológico , Vocalização Animal , Animais , California , Oceano Pacífico
11.
J Wildl Dis ; 57(4): 959-963, 2021 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-34410420

RESUMO

Esophageal and pharyngeal obstruction are commonly reported in marine mammals, but asphyxiation from blowhole and nasal cavity obstruction has been reported only rarely: in two long-finned pilot whales (Globicephala melas), several harbor porpoises (Phocoena phocoena), and one common bottlenose dolphin (Tursiops truncatus). We describe two cases of blowhole obstruction and subsequent asphyxiation in bottlenose dolphins caused by eels. A whip eel (Bascanichthys scuticaris) was found obstructing the blowhole of a deceased dolphin from the Indian River Lagoon, Florida, US (2011) and a shrimp eel (Ophichthus gomesii) was found obstructing the blowhole of a deceased dolphin from Tampa Bay, Florida (2020). Normally, the respiratory and digestive tracts of cetaceans do not communicate. Consuming large or oddly shaped prey can result in laryngeal displacement and subsequent interaction between the two systems. It is likely the eels entered the oral cavity while the dolphins were consuming or playing with prey, and laryngeal displacement enabled the eels to slither into and become stuck in the nasal passage, causing asphyxiation. These novel findings underscore the importance of continued investigation into causes of mortality in stranded marine mammals and can contribute to the knowledge of feeding ecology in bottlenose dolphins. As changing environmental conditions contribute to shifts in prey availability and abundance, mortality due to prey-related asphyxiation could become more common in odontocetes.


Assuntos
Golfinho Nariz-de-Garrafa , Golfinhos Comuns , Animais , Enguias , Florida/epidemiologia , Cavidade Nasal
12.
Behav Processes ; 189: 104444, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34129937

RESUMO

Yawning is an involuntary action that begins with a slow opening of the mouth with inhalation, followed by a maximum gaping phase, and ends with a short exhalation and the closing of the mouth. A wide variety of vertebrate species, including humans, yawn. Here, we report underwater yawn-like behavior in three captive common bottlenose dolphins, inferred from 119-h of observations. Five cases of yawn-like behavior were selected out of 2045 open-mouth behaviors, after removing intentional open-mouth behaviors. Yawn-like behaviors were chosen that had a mouth open-close duration ratio of ≤ 1 (duration of Phase 3, the period of mouth closing after maximum opening, divided by the duration of Phase 1, the period of mouth opening from start to maximum opening). Naïve human evaluators selected "yawn-like" behaviors. All five cases of yawn-like behavior occurred during inactive periods, similar to human yawns. In three of the five cases, inactivity levels significantly decreased within 4 min after the yawn-like behavior; therefore, yawn-like behavior in dolphins may increase their arousal level in drowsy states. Thus, the yawn-like behavior of dolphins, without breathing, is similar to yawning in terrestrial animals, including humans.


Assuntos
Golfinho Nariz-de-Garrafa , Golfinhos Comuns , Bocejo , Animais , Respiração
13.
Zoonoses Public Health ; 68(6): 691-695, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-33991441

RESUMO

Diphyllobothriosis caused by the Pacific broad tapeworm Adenocephalus pacificus (syn. Diphyllobothrium pacificum) is an emerging parasitic disease reported also from non-endemic areas, including Europe (Spain). The origin of these human cases is unknown but should be related to fresh marine fish imported from endemic areas. In this study, we molecularly confirmed common dolphins Delphinus delphis off Argentina as euparatenic transit hosts of A. pacificus. Preliminary analysis of their stomach content, together with data from previous studies from the Southwest Atlantic, showed that common dolphins feed almost exclusively on schooling Argentine hake Merluccius hubbsi and Argentine anchovy Engraulis anchoita. Therefore, we suggest that Argentine hake and Argentine anchovy may represent the intermediate hosts of A. pacificus in the Southwest Atlantic, but also in Europe to where M. hubbsi is imported on ice (unfrozen).


Assuntos
Golfinhos Comuns/parasitologia , Difilobotríase/veterinária , Reservatórios de Doenças/veterinária , Peixes/parasitologia , Microbiologia de Alimentos , Zoonoses/parasitologia , Animais , Argentina , Cestoides/isolamento & purificação , Difilobotríase/transmissão , Reservatórios de Doenças/parasitologia , Europa (Continente) , Humanos , Zoonoses/epidemiologia
14.
Mar Environ Res ; 168: 105305, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33773411

RESUMO

The Natura 2000 network is the centerpiece of the European Union conservation strategy to safeguard priority species and habitats. The question of whether other co-occurring species of conservation concern may also benefit from this network, however, remains largely unknown. Here, we used a systematic approach (MARXAN) for i) evaluating if the current Natura 2000 network in the Alboran Sea (western Mediterranean Sea), initially proposed to protect the common bottlenose dolphin (Tursiops truncatus) and priority habitats, is also spatially protecting the endangered common dolphin (Delphinus delphis), and ii) identifying additional marine areas that should be protected to reach adequate conservation targets for the common dolphin. While the current Natura 2000 network encompass ca. 22% of predicted abundances for common dolphins, this percentage might be enhanced by protecting coastal areas nearby the Strait of Gibraltar. However, dolphins and fisheries largely overlap spatially nearby the coastline, and only segregate in offshore areas that represent the marginal distribution of the species. Thus, conservation decision-makers must achieve a trade-off between cetacean conservation and fisheries by combining an area-based approach (i.e., new protected areas close to the Strait of Gibraltar) together with a basin-wide threat-based approach (e.g., regulation of fisheries).


Assuntos
Golfinho Nariz-de-Garrafa , Golfinhos Comuns , Animais , Pesqueiros , Gibraltar , Mar Mediterrâneo
15.
J Anim Ecol ; 90(6): 1583-1595, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33724460

RESUMO

Understanding the effect of stage-specific traits on species feeding habits can reveal how natural selection shapes life strategies. Amino acid (AA) nitrogen stable isotopes (δ15 N) provide multiple proxies of habitat baseline values and diet that can improve our understanding of species feeding strategies relative to their animal metabolism. We evaluated the effect of body length as a proxy for life stage and sex on the feeding habits of the common dolphin Delphinus delphis delphis using δ13 C and δ15 N in bulk tissue and AAs δ15 N from skin samples collected for almost two decades. For bulk δ13 C and δ15 N data, we used SIBER analysis to compare isotopic niches by sex and life stage. For AA δ15 N data, we developed a hierarchical Bayesian model (HBM) to estimate indices of trophic status (Δ15 N and trophic position). The model reflected the natural hierarchical structure of AA data by partitioning variability into three sources: between laboratory replicates, within dolphins and among dolphins. Estimates of Δ15 N based on all trophic and source AAs were more precise for each dolphin, less variable among dolphins and on average 2.4‰ higher than indices based on single trophic (Glx) and source (Phe) AAs. Precision was further increased when information was shared among individuals through random effects or regression models. Estimates of trophic position showed similar patterns. Both Δ15 N and δ15 Nbulk isotopic niches showed no difference by sex, suggesting that males and females have similar feeding habits and may not segregate. However, lower Δ15 N values for weaning calves and smaller juveniles discriminate them from adults, whereas δ15 N bulk isotopic niches do not. A trophic discrimination factor (TDFTro-Src ) of 3.1‰ was required for reasonable estimates of trophic position for these dolphins. Together, the lack of δ15 N differences between sexes, low variation between juveniles and adults and knowledge of common dolphins' social organization support intraspecific feeding cooperation as an important strategy to feed in the highly dynamic marine environment. Our study also presents an efficient way to analyse complex AA δ15 N data using HBM to investigate foraging behaviour in long-lived marine species difficult to study in the wild.


Assuntos
Golfinhos Comuns , Aminoácidos , Animais , Teorema de Bayes , Isótopos de Carbono , Feminino , Isótopos de Nitrogênio
16.
J Anim Ecol ; 90(5): 1191-1204, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33608907

RESUMO

Dolphin morbillivirus (DMV) is a virulent pathogen that causes high mortality outbreaks in delphinids globally and is spread via contact among individuals. Broadly ranging nearshore and open-ocean delphinids are likely reservoir populations that transmit DMV to estuarine populations. We assessed the seroprevalence of DMV antibodies and determined the habitat use of common bottlenose dolphins, Tursiops truncatus truncatus, from two estuarine sites, Barataria Bay and Mississippi Sound, in the northern Gulf of Mexico. We predicted that risk to DMV exposure in estuarine dolphins is driven by spatial overlap in habitat use with reservoir populations. Serum was collected from live-captured dolphins and tested for DMV antibodies. Habitat use of sampled individuals was determined by analysing satellite-tracked movements and stable isotope values. DMV seroprevalences were high among dolphins at Barataria Bay (37%) and Mississippi Sound (44%), but varied differently within sites. Ranging patterns of Barataria Bay dolphins were categorized into two groups: Interior and Island-associated. DMV seroprevalences were absent in Interior dolphins (0%) but high in Island-associated dolphins (45%). Ranging patterns of Mississippi Sound dolphins were categorized into three groups: Interior, Island-east and Island-west. DMV seroprevalences were detected across Mississippi Sound (Interior: 60%; Island-east: 20%; and Island-west: 43%). At both sites, dolphins in habitats with greater marine influence had enriched δ13 C values, and Barataria Bay dolphins with positive DMV titres had carbon isotope values indicative of marine habitats. Positive titres for DMV antibodies were more common in the lower versus upper parts of Barataria Bay but evenly distributed across Mississippi Sound. A dolphin's risk of exposure to DMV is influenced by how individual ranging patterns interact with environmental geography. Barataria Bay's partially enclosed geography likely limits the nearshore or open-ocean delphinids that carry DMV from interacting with dolphins that use interior, estuarine habitats, decreasing their exposure to DMV. Mississippi Sound's relatively open geography allows for greater spatial overlap and mixing among estuarine, nearshore and/or open-ocean cetaceans. The spread of DMV, and likely other diseases, is affected by the combination of individual movements, habitat use and the environment.


Assuntos
Golfinho Nariz-de-Garrafa , Golfinhos Comuns , Morbillivirus , Animais , Ecossistema , Golfo do México , Estudos Soroepidemiológicos
17.
Mitochondrial DNA A DNA Mapp Seq Anal ; 31(6): 257-264, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32654598

RESUMO

Our study aims to assess the population connectivity, evolutionary history, and conservation status of the short-beaked common dolphin in the Black Sea and Turkish Straits System (TSS). We also include DNA sequences from the Atlantic Ocean and the Mediterranean Sea to provide a regional perspective to our localized study. Analysis of 366 base pairs of mitochondrial DNA D-loop fragments from 37 samples collected from short-beaked common dolphins in the Black Sea, TSS, and Aegean Sea revealed 13 haplotypes, eight of which have not been previously reported. While analysis of samples archived on GenBank revealed 89 different haplotypes across the region. The haplotype network contains two main peripheral groups that include individuals from all locations. Haplotypes from the Atlantic Ocean are scattered across the network and no obvious population separation was detected. Some shared haplotypes potentially indicate multi-directional colonization events of the Mediterranean Sea from the eastern Atlantic Ocean. Moreover, some less widely distributed haplotypes suggest some level of more recent genetic connectivity through the Strait of Gibraltar and the TSS and point out the importance of these straits in the dispersal of short-beaked common dolphins. The haplotype and nucleotide diversity values were lower in the Black Sea, TSS, and western Mediterranean Sea when compared to the Atlantic Ocean, supporting the expansion of Atlantic populations into the Mediterranean and the Black Seas. Differentiation was observed between the Atlantic Ocean, and the Mediterranean Sea, TSS and the Black Sea based on Фst but not between Mediterranean and the Black Seas. For common dolphins, which have high dispersal potential, the protection of open seas and narrow seaways to enhance connectivity may be crucial.


Assuntos
Golfinhos Comuns/classificação , DNA Mitocondrial/genética , Mitocôndrias/genética , Análise de Sequência de DNA/métodos , Animais , Oceano Atlântico , Mar Negro , Golfinhos Comuns/genética , Conservação dos Recursos Naturais , Genética Populacional , Haplótipos , Mar Mediterrâneo , Mitocôndrias Cardíacas/genética , Pele/química
18.
Environ Pollut ; 263(Pt A): 114480, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32283460

RESUMO

Bioaccumulation of Hg and Cd from food is a complex ecological process that has been oversimplified in the past. Common dolphins (Delphinus delphis) provide a powerful model to biomonitor metal concentrations in marine environments worldwide. We combined proportions-based nutritional geometry with metal analysis, stomach content analysis and the proximate composition of prey, to yield novel insights into the accumulation of Hg and Cd. Our analysis showed an age-related accumulation trend for Cd and Hg in kidney and liver, with highest concentrations found at 18 years of age. When viewed through the lens of nutritional ecology, Argentine anchovy (58.1 Mass %) and South American long-finned squid (22.7 Mass %), provided most of the dietary intake of protein (P) and lipids (L) (P:L ratio = 2.6:1.0) and also represented the main source for Cd and Hg levels accumulated in their bodies. This study presents unprecedented evidence on metal accumulation in relation to age and nutritional intake in a marine predator.


Assuntos
Golfinhos Comuns , Golfinhos , Mercúrio/análise , Poluentes Químicos da Água/análise , Animais , Argentina , Cádmio , Monitoramento Ambiental
19.
J Exp Biol ; 223(Pt 5)2020 03 03.
Artigo em Inglês | MEDLINE | ID: mdl-32041809

RESUMO

Assessment of the compressibility of marine mammal airways at depth is crucial to understanding vital physiological processes such as gas exchange during diving. Very few studies have directly assessed changes in cetacean and pinniped tracheobronchial shape, and none have quantified changes in volume with increasing pressure. A harbor seal, gray seal, harp seal, harbor porpoise and common dolphin were imaged promptly post mortem via computed tomography in a radiolucent hyperbaric chamber. Volume reconstructions were performed of segments of the trachea and bronchi of the pinnipeds and bronchi of the cetaceans for each pressure treatment. All specimens examined demonstrated significant decreases in airway volume with increasing pressure, with those of the harbor seal and common dolphin nearing complete collapse at the highest pressures. The common dolphin bronchi demonstrated distinctly different compression dynamics between 50% and 100% lung inflation treatments, indicating the importance of air in maintaining patent airways, and collapse occurred caudally to cranially in the 50% treatment. Dynamics of the harbor seal and gray seal airways indicated that the trachea was less compliant than the bronchi. These findings indicate potential species-specific variability in airway compliance, and cessation of gas exchange may occur at greater depths than those predicted in models assuming rigid airways. This may potentially increase the likelihood of decompression sickness in these animals during diving.


Assuntos
Golfinhos Comuns/fisiologia , Mergulho/fisiologia , Phocoena/fisiologia , Focas Verdadeiras/fisiologia , Traqueia/fisiologia , Animais , Pressão , Mecânica Respiratória/fisiologia
20.
Dis Aquat Organ ; 136(3): 265-271, 2019 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-31724559

RESUMO

Bilateral nephrolithiasis with a concurrent vaginal calculus was identified in a stranded free-ranging long-beaked common dolphin Delphinus capensis. Necropsy and radiologic examinations of the sexually mature D. capensis revealed multiple small irregularly round nephroliths and a 6.4 × 4.1 × 9.2 cm vaginal calculus weighing 182 g. Nephroliths numbered 68 and 71 in the left and right kidneys, respectively, and ranged from 1.7 to 6.9 mm in diameter. Nephroliths were composed of 100% ammonium urate, which has been found in captive dolphin populations. However, the vaginolith consisted of struvite and calcium carbonate suggesting an alternate etiology. The composition of the vaginolith suggests that bacterial vaginitis could have served as the predisposing condition. Renal lesions included chronic tubulointerstitial nephritis with tubular degeneration and loss, likely secondary to the nephroliths. The pathogenesis of ammonium urate nephrolithiasis in managed care is suspected to be linked to diet and age but in this case may be due to metabolic disruption. However, if environmental changes cause a shift in prey species, the risk of nephrolithiasis in free-ranging cetaceans could increase. Careful surveillance for nephroliths in free-ranging populations should be considered by researchers.


Assuntos
Cálculos , Golfinhos Comuns , Animais , Feminino , Rim , Nefrolitíase , Vagina
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