Smelly shark, smelly ray: what is infecting you?

AIMS: Although elasmobranchs are consumed worldwide, bacteriological assessments for this group are still sorely lacking. In this context, this study assessed bacteria of sharks and rays from one of the most important landing ports along the Rio de Janeiro coast. METHODS AND RESULTS: Bacteria were isolated from the cloacal swabs of the sampled elasmobranchs. They were cultured, and Vibrio, Aeromonas, and Enterobacterales were isolated and identified. The isolated bacteria were then biochemically identified and antimicrobial susceptibility assays were performed. Antigenic characterizations were performed for Salmonella spp. and Polymerase Chain Reaction (PCR) assays were performed to identify Escherichia coli pathotypes. Several bacteria of interest in the One Health context were detected. The most prevalent Enterobacterales were Morganella morganii and Citrobacter freundii, while Vibrio harveyi and Vibrio fluvialis were the most prevalent among Vibrio spp. and Aeromonas allosacharophila and Aeromonas veronii bv. veronii were the most frequent among Aeromonas spp. Several bacteria also displayed antimicrobial resistance, indicative of Public Health concerns. A total of 10% of Vibrio strains were resistant to trimethoprim-sulfamethoxazole and 40% displayed intermediate resistance to cefoxitin. Salmonella enterica strains displayed intermediate resistance to ciprofloxacin, nalidixic acid and streptomycin. All V. cholerae strains were identified as non-O1/non-O139. The detected E. coli strains did not exhibit pathogenicity genes. This is the first study to perform serology assessments for S. enterica subsp. enterica isolated from elasmobranchs, identifying the zoonotic Typhimurium serovar. Salmonella serology evaluations are, therefore, paramount to identify the importance of elasmobranchs in the epidemiological salmonellosis chain. CONCLUSIONS: The detection of several pathogenic and antibiotic-resistant bacteria may pose significant Public Health risks in Brazil, due to high elasmobranch consumption rates, indicating the urgent need for further bacteriological assessments in this group.

Seascape Genetics of the Atlantic Spotted Dolphin (Stenella frontalis) Based on Mitochondrial DNA.

The Atlantic spotted dolphin (Stenella frontalis) is endemic to tropical, subtropical, and warm temperate waters of the Atlantic Ocean. Throughout its distribution, both geographic distance and environmental variation may contribute to population structure of the species. In this study, we follow a seascape genetics approach to investigate population differentiation of Atlantic spotted dolphins based on a large worldwide dataset and the relationship with marine environmental variables. The results revealed that the Atlantic spotted dolphin exhibits population genetic structure across its distribution based on mitochondrial DNA control region (mtDNA-CR) data. Analyses based on the contemporary landscape suggested, at both the individual and population level, that the population genetic structure is consistent with the isolation-by-distance model. However, because geography and environmental matrices were correlated, and because in some, but not all analyses, we found a significant effect for the environment, we cannot rule out the addition contribution of environmental factors in structuring genetic variation. Future analyses based on nuclear data are needed to evaluate whether local processes, such as social structure and some level of philopatry within populations, may be contributing to the associations among genetic structure, geographic, and environmental distance.

Osteochondromatosis (multiple cartilaginous exostoses) in an immature killer whale Orcinus orca.

An immature killer whale Orcinus orca found dead on the southeastern Brazilian coast had multiple bone proliferations: on the skull, vertebrae, hemal arches, and ribs. The bony formations were characterized as multiple osteochondromas, as defined by osteochondromatosis. The diagnosis was based on macroscopic and radiographic observations. These benign osseocartilaginous tumors affect young individuals and grow until skeletal maturity is achieved. Case reports of this condition, besides humans, include other mammals, with most reports for pets and domestic mammals such as cattle, and a report in a fossil canid (Hesperocyon) from the Oligocene. The etiology, diagnosis, developmental characteristics, and occurrence of osteochondromas are distinct among different species. This report describes the first case of multiple osteochondromas in a wild cetacean.

PCB and PBDE contamination in Tursiops truncatus and Stenella frontalis, two data-deficient threatened dolphin species from the Brazilian coast.

Polychlorinated biphenyls (PCB) and polybrominated diphenyl ethers (PBDE) levels were assessed in the liver and muscle of two data-deficient threatened dolphin species, the bottlenose dolphin (Tursiops truncatus, n = 4) and the Atlantic spotted dolphin (Stenella frontalis, n = 6), sampled off the Southeastern Brazilian coast. PCB concentrations were greater in liver compared to muscle, with males presenting higher concentrations than females. The three main detected PCB congeners were PCBs 138, 153 and 180. A predominance of hexachlorinated congeners was observed, followed by hepta- and penta-PCBs. For both species, Cl 3 and Cl 4 levels were higher in muscle compared to liver, while Cl 5 to Cl 8 and ∑PCBs were higher in liver. PBDE concentrations were significantly higher in Atlantic spotted dolphin muscle and liver compared to bottlenose dolphins. Similarly to PCBs, the highest PBDE concentrations were observed in males. The presence of PBDE congeners BDE-47, -100 and -99 in the muscle and liver of both species suggests the existence of a pollution source in Brazil by a penta-BDE mixture, as PBDEs have never been produced in Brazil. Interspecific PCB and PBDE profiles were very similar, which may be related to the similar characteristics of the analyzed species, mainly geographic distribution and life and feeding habits. This study furthers knowledge on environmental PCB and PBDE contamination, assisting in the establishment of dolphin population conservation strategies. In addition, this study calls into question the current threshold values established for PCBs and PBDEs, and demonstrates the lack of information and knowledge in this regard for cetaceans.

Guiana dolphins (Sotalia guianensis) as marine ecosystem sentinels: ecotoxicology and emerging diseases.

Guiana dolphins (Sotalia guianensis) are small cetaceans that inhabit coastal regions down to a 50 m depth. As a coastally distributed species, they are exposed to a variety of human-induced risks that include passive fishing nets, persistent environmental pollution, and emerging diseases. As a top predatorS. guianensis occupies an important ecological niche in marine ecosystems. However, this niche also exposes this dolphin to extensive biomagnification of marine contaminants that may accumulate and be stored throughout their life of about 30 years.In this paper, we have compiled available data on the Guiana dolphin as regards its exposure to chemical pollutants, pathogenic microbes, infectious diseases, and injuries caused by interactions with passive fishing gears. Our analysis of the data shows that Guiana dolphins are particularly sensitive to environmental changes.Although the major mortal threat to dolphins results from contact with fishing other human-related activities in coastal zones also pose risks and need more attention.Such human-related risks include the presence of persistent toxicants in the marine environment, such as PCBs and PBDEs. Residues of these chemicals have been detected in Guiana dolphin's tissues at similar or higher levels that exist in cetaceans from other known polluted areas. Another risk encountered by this species is the non lethal injuries caused by fishing gear. Several incidents of this sort have occurred along the Brazilian coast with this species. When injuries are produced by interaction with fishing gear, the dorsal fin is the part of the dolphin anatomy that is more affected, commonly causing severe laceration or even total loss.The Guiana dolphins also face risks from infectious diseases. The major ones thus far identified include giardiasis, lobomycosis, toxoplasmosis, skin and skeletal lesions. Many bacterial pathogens from the family Aeromonadaceae and Vibrionaceae have been isolated from Guiana dolphins. Several helminth species have also been observed to affectS. guianensis. These results suggest a vulnerability of this species to environmental disturbances. Moreover, there is some evidence that the effects of some infectious diseases may be enhanced from stress caused by habitat impairment. For example, certain diseases and pathogenic organisms in S.guianensis may be associated with the high levels of endocrine-disruptor contaminants(e.g., PCBs; DDTs; PBDEs) that have been detected in marine waters.Although the data available on S. guianensis is growing, most of the work has been focused on a small portion of the species total area of distribution. Most studies,to date, have been carried out in the Southern region of the distribution, and in north eastern Brazil. Few studies have been conducted in the northern region of the South America or in Central America. Therefore, future studies should be conducted that address the heterogeneity of this species total distribution.The biology and ecology of the Guiana dolphin renders this species potentially useful as a sentinel species for detecting environmental changes, such as chemical and biological pollution. Research about this dolphin is encouraged as a way to assess what coastal environmental changes have occurred and to continue evaluating the health status of this vulnerable species in a changing environment.

Differences in methylmercury and inorganic mercury biomagnification in a tropical marine food web.

Methylmercury (MeHg), inorganic mercury (Hginorg) and their biomagnification factors (BMF) were evaluated along a non-degraded Brazilian bay food web. Highly significant differences (p < 0.0001) were found between MeHg and Hginorg concentrations among all organisms (microplankton, shrimp, fish and dolphin). MeHg increased with increasing trophic position while Hginorg did not present the same pattern. BMF values for MeHg were higher than 1 for all trophic interactions from source to consumer, indicating that MeHg was transferred more efficiently and biomagnified over the entire web. Only one BMF exceeding one was observed for Hginorg (27) between microplankton and their consumer, planktivorous fish. BMF values for Hginorg were significantly different than those found for MeHg (20) at the base of the food web.

Metal and metalloid maternal transfer in a newborn West Indian manatee (Trichechus manatus) two years after the northeastern oil spill disaster of 2019 in Brazil.

A large-scale oil spill along the northeastern Brazilian coast in 2019-2020 severely impacted primary manatee habitats in Brazil. This study aimed to assess metal and metalloid contamination in a dead manatee calf found following this oil spill. Several elements were detected, including chromium, iron, nickel, lead, and vanadium, which are crude oil components, and thallium, a component of dispersants used to degrade and dissipate crude oil. The presence of these contaminants in the manatee calf is indicative of maternal exposure, metabolism, and newborn transference via placenta and lactation. This is the first report of mother-calf metal transfer in manatees, highlighting the species' vulnerability and potential long-term population dynamics effects, and the first report for several metals and metalloids in these animals, laying the foundation for future research efforts. These findings highlight the urgent need for continued environmental monitoring, ecotoxicological assessments, and conservation initiatives.

Cultivable Fungi from Amazon River Dolphins Engaged in Wildlife Ecotourism in the Anavilhanas National Park, Brazil.

Amazon River dolphins are an important flagship species in the Anavilhanas National Park, Brazil, where they interact with visitors. This study aimed to quantify and identify fungi isolated from dolphin skin and oral samples and their surrounding environment in this unique ecosystem. Samples were collected from three dolphins and water samples from Flutuante dos Botos and the Novo Airão city harbor. Fungi were isolated using culture media and identified through micromorphology assays and ITS region sequencing. Oral swab samples resulted in culture of Trichosporon montevideense and Exophiala dermatitidis. Skin samples from one dolphin revealed Toxicocladosporium irritans and Diaporthe lithocarpus. Water samples exhibited higher fungal counts and diversity, with Rhodotorula mucilaginosa, Exophiala dermatitidis, Penicillium citrinum, Fomitopsis meliae, and Nectria pseudotrichia identified at the collection site and Candida spencermartinsiae and Penicillium chermesinum at the city harbor. This study provides important insights into the fungal diversity associated with Amazon River dolphins and their environment, enhancing our understanding of the public health and ecological dynamics in the Anavilhanas National Park.

Prevalence of smoking habits, attitudes and knowledge on counteractive strategies among a sample of healthcare employees: results of the smoking-free health environments project in the province of Palermo, Italy.

Introduction: Tobacco use is responsible for over 7 million deaths annually, making smoking the leading cause of preventable mortality globally. Over the last two decades in Italy, the prevalence of smoking among physicians has consistently decreased, while it remains higher and is gradually decreasing among non-physician healthcare workers. The aim of this study was to investigate the Prevalence of smoking habits, attitudes, and knowledge on counteractive strategies among employees in the Primary Healthcare Facilities in the Province of Palermo, Italy. Methods: A cross-sectional survey was conducted between June 2020 and December 2020 through a previously validated anonymous questionnaire structured in four sections including 34 items. Data were analyzed using Stata/MP 12.1 statistical software. Results: Overall, 2,645 participants answered the questionnaire. The prevalence of either current or former smokers was 18.6%. Based on the multivariable analysis conducted, a significantly higher frequency of current smokers was observed among male participants (AdjOR: 1.29; CI95%: 1.02-1.64) and those belonging to the Surgical Unit (AdjOR: 1.92; CI95%: 1.27-2.90). Conversely, the prevalence of current smokers was significantly lower among those with at least one child (AdjOR: 0.67; CI95%: 0.49-0.91), with an educational qualification equal to or greater than a graduation degree (AdjOR: 0.56; CI95%: 0.43-0.73), those who considered second-hand smoke harmful (AdjOR: 0.06; CI95%: 0.008-0.60), those who had observed smoking or detected the smell of smoke in their workplace (AdjOR: 0.64; CI95%: 0.45-0.91). Furthermore, the prevalence of current smokers was significantly lower among participants who believed that healthcare professionals could play a crucial role in influencing their patients' lifestyles (AdjOR: 0.67; CI95%: 0.50-0.90) and among those who recommend their patients to quit smoking (AdjOR: 0.35; CI95%: 0.24-0.51). Discussion: The results of the current research demonstrate that, despite the decline in smoking prevalence among physicians, the rate of smokers among healthcare facility employees remains unacceptably high. This underscores the need to re-evaluate current anti-tobacco strategies in the workplace.

Small cetaceans found stranded or accidentally captured in southeastern Brazil: bioindicators of essential and non-essential trace elements in the environment.

Essential (Cu, Mn, Se and Zn) and non-essential (Cd and Hg) elements were analyzed in the hepatic tissue of 22 individuals of seven different species of small cetaceans (Feresa attenuata; Orcinus orca; Pontoporia blainvillei; Sotalia guianensis; Stenella frontalis; Steno bredanensis; Tursiops truncatus) accidentally caught in fishing nets or found stranded along the northern coast of the state of Rio de Janeiro, Brazil, between 2001 and 2010. Atlantic spotted dolphin (S. frontalis) showed the highest levels of Cd (20.23µgg(-1), dry weight), while rough-toothed dolphin (S. bredanensis) showed the highest levels of Hg (825.9µgg(-1)dw) and Se (221.9µgg(-1)dw). Killer whale (O. orca) presented the highest levels of Cu (64.80µgg(-1)dw) and Zn (2220µgg(-1)dw), and Guiana dolphin (S. guianensis), the highest level of Mn (13.05µgg(-1)dw). Cu, Hg, Mn and Zn in the hepatic tissue of killer whale (O. orca), Cu, Hg, Mn, Se and Zn in the hepatic tissue of rough-toothed dolphin (S. bredanensis) and Cd and Zn in the hepatic tissue of Guiana dolphin (S. guianensis) were significantly higher when compared to other studies with these species around the world. No significant correlations were observed between element accumulation and sex, sexual maturity and body length. An analysis of the interelemental relationships in the Guiana dolphin specimens showed strong positive correlations between Cd and Se, Cu and Zn, and Hg and Se. Differences were observed in the bioaccumulation of elements between the analyzed species, probably related to each species feeding habit, and differences between different element concentrations in the different dolphin species were probably due to the preference for certain preys and their bioavailability in the environment. Thus, the bioavailability of the analyzed elements in the marine environment should also be taken in consideration. This study also presents the first data ever reported for pygmy killer whale (F. attenuata) regarding trace element concentrations in hepatic tissue.

Cranial asymmetry in odontocetes: a facilitator of sonic exploration?

Directional cranial asymmetry is an intriguing condition that has evolved in all odontocetes which has mostly been associated with sound production for echolocation. In this study, we investigated how cranial asymmetry varies across odontocete species both in terms of quality (i.e., shape), and quantity (magnitude of deviation from symmetry). We investigated 72 species across all ten families of Odontoceti using two-dimensional geometric morphometrics. The average asymmetric shape was largely consistent across odontocetes - the rostral tip, maxillae, antorbital notches and braincase, as well as the suture crest between the frontal and interparietal bones were displaced to the right, whereas the nasal septum and premaxillae showed leftward shifts, in concert with an enlargement of the right premaxilla and maxilla. A clear phylogenetic signal related to asymmetric shape variation was identified across odontocetes using squared-change parsimony. The magnitude of asymmetry was widely variable across Odontoceti, with greatest asymmetry in Kogiidae, Monodontidae and Globicephalinae, followed by Physeteridae, Platanistidae and Lipotidae, while the asymmetry was lowest in Lissodelphininae, Phocoenidae, Iniidae and Pontoporiidae. Ziphiidae presented a wide spectrum of asymmetry. Generalized linear models explaining magnitude of asymmetry found associations with click source level while accounting for cranial size. Using phylogenetic generalized least squares, we reconfirm that source level and centroid size significantly predict the level of cranial asymmetry, with more asymmetric marine taxa generally consisting of bigger species emitting higher output sonar signal, i.e. louder sounds. Both characteristics theoretically support foraging at depth, the former by allowing extended diving and the latter being adaptive for prey detection at longer distances. Thus, cranial asymmetry seems to be an evolutionary pathway that allows odontocetes to devote more space for sound-generating structures associated with echolocation and thus increases biosonar search range and foraging efficiency beyond simple phylogenetic scaling predictions.

Trophic Chain Organochlorine Pesticide Contamination in a Highly Productive Upwelling Area in Southeastern Brazil.

Organochlorine pesticides (OCP) are legacy anthropogenic compounds known to persist for several years in the environment. The continuous use of some OCP, such as DDT, after restrictions in developing countries are cause of concern, due to their deleterious effects to marine life and humans. Studies assessing OCP contamination in coastal environments are still scarce in South America and there is a need to understand the impacts from trophic chain accumulation of these pollutants in marine life. In this study, we have assessed OCP levels in muscle and liver and estimated the biomagnification factor in several upwelling system trophic chain members, including fish, squid, and marine mammal from Southeastern Brazil. DDT degradation product DDE was the OCP detected in the highest concentrations in Franciscana dolphins (Pontoporia blainvillei), 86.4 ng·g-1 wet weight, and fish muscle and liver. In general, higher OCP levels were found in liver than in muscle, except for croaker. Biomagnification factors (BMF) of OCP in the top predator P. blainvillei and the carnivorous cutlass fish (Trichiurus lepturus) were on average between 0.2 and 1.8. Continued OCP monitoring in this region is warranted to better understand the distribution and fate of these compounds over time, with the goal to establish strategies for the conservation of local dolphin species and to assess human health risks from local coastal region populations.

Mobilization of persistent organic pollutants in humpback whales: Insights from feeding areas in the Antarctic peninsula and Strait of Magellan to migration, breeding, and calving grounds along the Brazilian coast.

Southern Hemisphere Megaptera novaeangliae undertake the longest migration, which reflect their exposure to lipophilic contaminants. To assess these changes, persistent organic pollutants were analyzed in blubber samples of humpback whales from three regions: the Antarctic Peninsula (n = 46), the Strait of Magellan, Chile (n = 22), and the Brazilian coast (n = 38). The similarity in PCB and HCB levels between individuals from feeding grounds and breeding grounds suggests contamination during feeding. The whales around the Antarctic Peninsula exhibited a predominance of tetrachlorobiphenyl PCBs. Whales feeding in the Strait of Magellan showed a slight prevalence of 5Cl biphenyls, likely due to their consumption of subantarctic krill species as well as small fishes potentially contaminated by industrial activities in Chile. The dominance of 5-6Cl congeners in whales in Brazil, may be attributed to the extreme physiological changes during fasting when whales utilize blubber reserves and metabolize lighter congeners, or transfer them to their calves.

Detection of Escherichia coli and other Enterobacteriales members in seabirds sampled along the Brazilian coast.

Escherichia coli, an Enterobacterales member, is a normal representative of the microbiota of homeothermic animals. Most strains are commensal, but several pathotypes can cause disease, and numerous antimicrobial resistance factors have been identified. These bacteria have spread rapidly in recent years, highlighting the importance of screening the environment and non-human reservoirs for virulent strains and/or those presenting resistance factors, in addition to other microorganisms of public health importance. In this context, this study aimed to survey Enterobacteriales present in seabirds sampled along the Brazilian coast, comparing findings between migratory and resident birds, as well as between wrecked and non-wrecked animals. Escherichia coli pathotypes were also characterized through rapid seroagglutination and polymerase chain reaction techniques and antimicrobial resistance profiles were investigated through the disc agar diffusion method. Cloacal, ocular, oral, tracheal, and skin lesion swabs, as well as fresh feces, were collected from 122 seabirds. The findings indicate these animals as important hosts for opportunistic human pathogens. Escherichia coli strains were identified in 70 % of the analyzed seabirds, 62 % of which displaying resistant or intermediate profiles to at least one antimicrobial, while 7% were multiresistant. Resistance to tetracycline (22 %), nalidixic acid (15 %), trimethoprim-sulfamethozaxol (14 %) and ampicillin (12 %) were the most prevalent. Resistance to cefoxitin, a critically important antimicrobial for human medicine, was also detected. Virulence genes for one of the EAEC, ETEC or EPEC pathotypes were detected in 30 % of the identified strains, the first two described in seabirds for the first time. The EAEC gene was detected in 25 % of the sampled seabirds, all resident, 8 % of which exhibited a multidrug-resistant profile. Thus, seabirds comprise important reservoirs for this pathotype. Escherichia coli was proven an ubiquitous and well-distributed bacterium, present in all evaluated bird species and sampling sites (except Marajó Island). According to the chi-square test, no significant differences between E. coli prevalences or antimicrobial resistance profiles between migratory and resident and between wrecked and non-wrecked seabirds were observed. Thus, migratory birds do not seem to contribute significantly to E. coli frequencies, pathotypes or antimicrobial resistance rates on the Brazilian coast.

Guiana dolphins (Sotalia guianensis, Van Benédén 1864) as indicators of the bioaccumulation of total mercury along the coast of Rio de Janeiro state, Southeastern Brazil.

Total mercury (Hg) was determined in muscle tissue of 20 Guiana dolphins stranded along the coast of Rio de Janeiro state, Brazil, with a mean of 1.07 µg/g wet weight. Mercury concentrations were positively related to body length, possibly related to the capacity of the dolphins to bioaccumulate this element throughout life. The Hg concentrations were not significantly different between males and females, although females (1.08 µg/g) showed slightly higher levels than males (1.04 µg/g). Concentrations were low when compared to results of studies carried out with small cetaceans in the Northern Hemisphere, and with previous studies in the Southeastern Brazil.

Mercury status of the Amazon Continental Shelf: Guiana dolphins (Sotalia guianensis, Van Benédén 1864) as a bioindicator.

Total mercury (Hg) was analyzed in muscle tissue of 27 accidentally captured Guiana dolphins (Sotalia guianensis) in order to evaluate Hg contamination levels present in the Amazon Continental Shelf, in Amapá state, North Brazil. The samples showed a mean concentration of 0.4 ± 0.16 µg/g wet weight (ww), ranging from 0.07 to 0.79 µg/g ww. As observed in several other cetacean species, Hg concentrations presented positive correlations to body length, related to the capacity to bioaccumulate this element throughout life. Hg concentrations were not significantly different between males (mean = 0.38 µg/g ww; n = 15) and females (mean = 0.42 µg/g ww; n = 12). Concentrations were low when compared to results of studies carried out with small cetaceans in the Northern Hemisphere, and with some previous studies in the south-eastern region of Brazil. In contrast with high Hg concentrations normally detected in river dolphin samples from Amazon River tributaries, our results suggest that the Amazon coast contains low levels of Hg in bioavailable form.

Elasmobranch-associated microbiota: a scientometric literature review.

Elasmobranchs provide greatly relevant ecosystem services for the balance of the environments in which they are inserted. In recent decades, sharp population declines have been reported for many species in different regions worldwide, making this taxonomic group currently one of the most threatened with extinction. This scenario is almost entirely due to excessive fishing pressure, but any contributing factor that may cause additional mortality to populations must be mapped and monitored. In a fast-changing world, emerging marine pollution associated with climate change display the potential to increase the spread of infectious agents. These can, in turn, lead to mortality events, both directly and indirectly, by reducing immune responses and the physical and nutritional condition of affected individuals. In this context, the present study aimed to analyze data concerning elasmobranch-associated microbiota, identifying study trends and knowledge gaps in order to direct future studies on this topic of growing relevance for the health of wild populations, as well as individuals maintained in captivity, considering the zoonotic potential of these microorganisms.

Karyotypical Confirmation of Natural Hybridization between Two Manatee Species, Trichechus manatus and Trichechus inunguis.

Two species of manatees are found in Northern Brazil-the Antillean manatee (Trichechus manatus), which is found along the coast from Florida to Northeastern Brazil, and the Amazonian manatee (Trichechus inunguis), endemic to the Amazon drainage basin. These species show a sympatric distribution in the region of the Marajó Archipelago, an estuarine area surrounding the Amazon River mouth. There is evidence of the occurrence of interspecific hybrids in this area, based on mitochondrial DNA analyses, although the use of nuclear markers has not corroborated this proposal. Considering that these species show very distinct karyotypes, despite being closely related (2n = 48 in T. manatus and 2n = 56 in T. inunguis), hybrids would present distinct chromosome numbers. Based on this, we conducted cytogenetic analyses using classic and molecular techniques in three calves found stranded in the Marajó Island and Amapá coast. The results showed that one of them, morphologically classified as T. inunguis, presented the correspondent karyotype, with 2n = 56. However, the other two, which were phenotypically similar to T. manatus, showed 2n = 49. Despite the same diploid number, their G-banding patterns revealed some differences. The results of the distribution of some microsatellite sequences have also confirmed the heterozygosity of some chromosomal pairs in these two individuals. These results are the first indubitable confirmation of the occurrence of natural hybrids between T. manatus and T. inunguis, and also brings about some issues concerning the viability of hybrids, considering that these two individuals do not correspond to an F1 hybrid, but instead, both presented a possible F2 karyotype.

Mitochondrial diversity and inter-specific phylogeny among dolphins of the genus Stenella in the Southwest Atlantic Ocean.

The genus Stenella is comprised of five species occurring in all oceans. Despite its wide distribution, genetic diversity information on these species is still scarce especially in the Southwest Atlantic Ocean. Some features of this genus can enhance opportunities for potential introgressive hybridization, e.g. sympatric distibution along the Brazilian coast, mixed known associations among species, karyotype uniformity and genome permeability. In this study we analyzed three genes of the mitochondrial genome to investigate the genetic diversity and occurrence of genetic mixture among eighty specimens of Stenella. All species exhibited moderate to high levels of genetic diversity (h = 0.833 to h = 1.000 and π = 0.006 to π = 0.015). Specimens of S. longirostris, S. attenuata and S. frontalis were clustered into differentiated haplogroups, in contrast, haplotypes of S. coeruleoalba and S. clymene were clustered together. We detected phylogenetic structure of mixed clades for S. clymene and S. coeruleoalba specimens, in the Southwest Atlantic Ocean, and also between S. frontalis and S. attenuata in the Northeast Atlantic Ocean, and between S. frontalis and S. longirostris in the Northwest Atlantic Ocean. These specimes were morphologically identified as one species but exhibited the maternal lineage of another species, by mitochondrial DNA. Our results demonstrate that ongoing gene flow is occurring among species of the genus Stenella reinforcing that this process could be one of the reasons for the confusing taxonomy and difficulties in elucidating phylogenetic relationships within this group.

Arsenic contamination in widely consumed Caribbean sharpnose sharks in southeastern Brazil: Baseline data and concerns regarding fisheries resources.

Although shark meat is consumed worldwide, elevated arsenic (As) concentrations have been increasingly reported. The Caribbean sharpnose shark (Rhizoprionodon porosus) is a widely consumed fishing resource in Brazil, with scarce information on As burdens to date. Herein, commercial-sized juvenile Caribbean sharpnose sharks from Rio de Janeiro (Brazil) were assessed in this regard, presenting significantly higher hepatic As concentrations in males (8.24 ± 1.20 mg kg-1 wet weight; n = 12) compared to females (6.59 ± 1.87 mg kg-1 w.w.; n = 8), and a positive correlation (r = 0.74) was noted between female muscle and liver As concentrations, indicating systemic inter-tissue transport not evidenced in males. Arsenic concentrations were over the maximum permissible As limit established in Brazilian legislation for seafood and calculated Target Hazard Quotients suggest consumption risks, although cancer risks were not evidenced. Therefore, Public Health concerns with regard to Caribbean sharpnose shark As burdens deserve careful attention.