RESUMO
Environmental pollution and climate change are causing major changes in the marine environment. Coastal zones around the world are experiencing changes such as nutrient influx, resulting in altered plankton communities. The aim of this study was to determine the response of zooplankton to the changes in the environmental variables in the coastal zone of the Arabian Sea, Southwest Coast of India, over 10 years. Zooplankton abundance, chlorophyll-a concentrations, and water quality variables (rainfall, nitrates, phosphates, pH, water temperature, and salinity) were quantified from January 2010 to December 2019. Water temperature, pH, salinity, and phosphates increased steadily across the sites during the study period whereas chlorophyll-a and nitrates decreased. Rainfall abundance was not exhibiting any patterns or trends. The effects of the sampled environmental variables on zooplankton abundance were tested using generalized linear mixed models. Salinity and phosphates negatively affected the zooplankton abundance whereas water temperature, pH, and chlorophyll-a concentration had a positive effect. Coastal zones in southwest India are experiencing declining phytoplankton abundance due to a number of environmental factors. Reduced phytoplankton combined with altered environmental variables are having declining effects on zooplankton. This decline in zooplankton population has far reaching effects on biota in higher trophic levels including economically important organisms such as fishes.
Assuntos
Monitoramento Ambiental , Zooplâncton , Animais , Clorofila A , Fitoplâncton , PlânctonRESUMO
Anthropogenic activities have increased the discharge of marine contaminants threatening marine life. Small gulfs, such as the Arabian Gulf, are vulnerable to accumulating potentially toxic elements in marine species due to slow water exchange. The concentration of 21 elements was determined in the tissues of Scomberomorus commerson from Umm Al Quwain (United Arab Emirates) and Bandar Abbas (Iran). Chromium, Copper, and Iron exceeded internationally established maximum permissible limits. Sites could not be distinguished based on Principle Component Analyses of elements. Elevated Cu and Cr in muscle are of concern to marine species as well as humans. Metal Pollution Index showed a significant difference between sites, with 20.34 % and 100 % of individuals suffering high metal toxicity and poor body conditions, respectively. The Arabian Gulf is experiencing an increase in discharge of industrial wastes. Implementation of strict policies to reduce discharge of toxic substances is required to protect marine organisms and humans.
Assuntos
Metais Pesados , Perciformes , Poluentes Químicos da Água , Humanos , Animais , Metais Pesados/análise , Peixes , Cobre/análise , Resíduos Industriais/análise , Poluentes Químicos da Água/análise , Monitoramento AmbientalRESUMO
Background and Aim: Ostrich (Struthio camelus) farming in the United Arab Emirates (UAE) is a relatively new field of farming. Farmed ostriches are susceptible to ectoparasite infestation, which affects their production. This study was conducted to estimate the prevalence of ectoparasites on ostriches raised on a farm in Abu Dhabi Emirate. Materials and Methods: The feathers of 42 ostriches (26 females and 16 males) were collected and morphologically examined for ectoparasites. In total, 283 lice (89 males and 194 females) were collected from birds. However, there were no ticks or other ectoparasites. Lice were preserved in 1.5 mL tubes containing 70% ethanol and were later identified using taxonomic keys. The prevalence, mean intensity of infection, and mean abundance were estimated. Results: One louse species, Struthiolipeurus struthionis was identified. To the best of our knowledge, this is the first report of S. struthionis in ostriches raised in the UAE with an overall prevalence of 88%. The prevalence of lice was significantly higher in July (100%) than that in May (66.7%). Likewise, the mean intensity and abundance of lice were significantly higher in June (10.6 and 9.94, respectively) than in May (3.25 and 2.2, respectively). Conclusion: The high prevalence of lice poses a serious risk to ostrich farming by negatively affecting the health and productivity of ostriches.
RESUMO
To evaluate the exposure risk and ingestion of microplastics by migratory shorebirds, which are regarded as apex predators in the coastal ecosystem, this study investigated the ubiquitous presence of microplastics in estuarine and coastal habitats and their potential to be transferred in the food chains. We analysed the presence of microplastics in water, sediment, major macroinvertebrate prey and the guano samples of ten shorebird species from ten important wintering grounds in the west coast of India. Our results revealed that water is the primary source through which microplastics disseminate into various ecosystem components. Microplastic debris in various forms were reported in all samples analysed, with microfibres being the most abundant form. While polyethylene and polypropylene were found as the major microplastic types in water, sediment, and prey samples, polystyrene was most abundant in guano samples. Microplastic transfer and impacts in this delicate ecosystem demand further investigations.
Assuntos
Microplásticos , Poluentes Químicos da Água , Ecossistema , Plásticos/análise , Monitoramento Ambiental/métodos , Poluentes Químicos da Água/análise , Água/análise , ÍndiaRESUMO
Haematophagous arthropods can harbor various pathogens including viruses, bacteria, protozoa, and nematodes. Insects possess an innate immune system comprising of both cellular and humoral components to fight against various infections. Haemocytes, the cellular components of haemolymph, are central to the insect immune system as their primary functions include phagocytosis, encapsulation, coagulation, detoxification, and storage and distribution of nutritive materials. Plasmatocytes and granulocytes are also involved in cellular defense responses. Blood-feeding arthropods, such as mosquitoes and ticks, can harbour a variety of viral pathogens that can cause infectious diseases in both human and animal hosts. Therefore, it is imperative to study the virus-vector-host relationships since arthropod vectors are important constituents of the ecosystem. Regardless of the complex immune response of these arthropod vectors, the viruses usually manage to survive and are transmitted to the eventual host. A multidisciplinary approach utilizing novel and strategic interventions is required to control ectoparasite infestations and block vector-borne transmission of viral pathogens to humans and animals. In this review, we discuss the arthropod immune response to viral infections with a primary focus on the innate immune responses of ticks and mosquitoes. We aim to summarize critically the vector immune system and their infection transmission strategies to mammalian hosts to foster debate that could help in developing new therapeutic strategies to protect human and animal hosts against arthropod-borne viral infections.
Assuntos
Artrópodes , Culicidae , Carrapatos , Viroses , Animais , Humanos , Ecossistema , Mosquitos Vetores , Vetores Artrópodes , Artrópodes/fisiologia , Interações Hospedeiro-Patógeno , MamíferosRESUMO
Heavy metal pollution in Indian wetlands is rising due to industrial, agricultural and urban development activities. Shorebirds occupy upper trophic levels and are therefore especially vulnerable to heavy metal pollution. We evaluated the concentration of heavy metals (zinc, copper, cobalt, chromium, lead and cadmium) in 22 common species of migrant shorebirds (220 shorebird dropping samples) with diverse foraging behaviors, in their different prey (55 prey samples) and in the sediments (90 sediment samples) in different habitat types (mudflats, mangroves and sand beaches) between 2019 and 2021. Further, we analyzed a total of 10 biofilm samples from mudflats and mangroves. We detected relatively low concentrations of heavy metals in the sediments (Zn concentration range: 9.11-40.91 mg/kg; Cu: 5.74-21.38 mg/kg; Co: 2.00-4.04 mg/kg; Cr: 4.05-41.03 mg/kg; Pb: 1.02-7.19 mg/kg; Cd: 0.56-4.35 mg/kg). However, we measured relatively high concentrations of heavy metals in invertebrate prey species (Zn concentration range: 84.72-224.74 mg/kg; Cu: 26.63-170.36 mg/kg; Co: 13.98-14.42 mg/kg; Cr: 14.78-98.16 mg/kg; Pb: 18.95-157.29 mg/kg; Cd: 9.33-60.56 mg/kg). In addition, we found high concentrations of heavy metals in shorebird droppings (Zn concentration range: 41.33-58.8 mg/kg; Cu: 31.42-52.11 mg/kg; Co: 36.34-55.68 mg/kg; Cr: 52.3-68.21 mg/kg; Pb: 25.94-43.13 mg/kg; Cd: 5.53-16.4 mg/kg). It is evident that concentration of heavy metals increased successively moving from sediment to prey to shorebird species, likely through trophic transfer. The biofilm samples contained very high concentrations of Cr, Pb and Cd (22.64, 28.09 and 18.46 mg/kg respectively) which could be harmful to biofilm grazing shorebirds. Since bioaccumulation of heavy metals entail risks in living species, we suggest that increasing concentrations may detrimentally affect physiological processes in invertebrates and shorebirds. There is an urgent need to identify the sources of pollution and to reduce the discharge of heavy metals and other pollutants into coastal and inland wetlands.
Assuntos
Metais Pesados , Poluentes Químicos da Água , Animais , Cobre , Cádmio , Áreas Alagadas , Chumbo , Sedimentos Geológicos , Monitoramento Ambiental , Poluentes Químicos da Água/análise , Metais Pesados/análise , Índia , Invertebrados , Medição de RiscoRESUMO
Background and Aim: Viruses are important components of the microbiome of ticks. Ticks are capable of transmitting several serious viral diseases to humans and animals. Hitherto, the composition of viral communities in Hyalomma dromedarii ticks associated with camels in the United Arab Emirates (UAE) remains unexplored. This study aimed to characterize the RNA virome diversity in male and female H. dromedarii ticks collected from camels in Al Ain, UAE. Materials and Methods: We collected ticks, extracted, and sequenced RNA, using Illumina (NovaSeq 6000) and Oxford Nanopore (MinION). Results: From the total generated sequencing reads, 180,559 (~0.35%) and 197,801 (~0.34%) reads were identified as virus-related reads in male and female tick samples, respectively. Taxonomic assignment of the viral sequencing reads was accomplished based on bioinformatic analyses. Further, viral reads were classified into 39 viral families. Poxiviridae, Phycodnaviridae, Phenuiviridae, Mimiviridae, and Polydnaviridae were the most abundant families in the tick viromes. Notably, we assembled the genomes of three RNA viruses, which were placed by phylogenetic analyses in clades that included the Bole tick virus. Conclusion: Overall, this study attempts to elucidate the RNA virome of ticks associated with camels in the UAE and the results obtained from this study improve the knowledge of the diversity of viruses in H. dromedarii ticks.
RESUMO
Oryctes agamemnon arabicus (Coleoptera: Scarabaeidae) is one of the main pests on date palm trees in the United Arab Emirates (UAE). Two mite species were found associated with this beetle: Sancassania sp. (Acari: Astigmata: Acaridae) and Hypoaspis rhinocerotis Oudemans (Acari: Mesostigmata: Laelapidae). Sancassania deutonymphs (hypopi) were phoretic on O. a. arabicus adults and larvae. However, they were also necromenic, because once the host dies they feed on its carcass. The highest deutonymph load was found in the subelytral space of O. a. arabicus adult. The phoretic and necromenic interactions between Sancassania sp. and O. a. arabicus need to be investigated in more detail. H. rhinocerotis was recorded for the first time in UAE. Its role has not yet been studied in the date palm agricultural ecosystem.
Assuntos
Ácaros e Carrapatos/fisiologia , Besouros/fisiologia , Ácaros e Carrapatos/classificação , Ácaros e Carrapatos/crescimento & desenvolvimento , Distribuição Animal , Animais , Arecaceae , Besouros/crescimento & desenvolvimento , Ecossistema , Feminino , Larva/crescimento & desenvolvimento , Larva/fisiologia , Masculino , Ninfa/classificação , Ninfa/crescimento & desenvolvimento , Ninfa/fisiologia , Caracteres Sexuais , Especificidade da Espécie , Simbiose , Emirados Árabes UnidosRESUMO
BACKGROUND: Hyalomma anatolicum is a widely distributed tick species that acts as a vector transmitting tick-borne pathogens (TBPs) in livestock. Such pathogens affect the health of livestock and consequently reduce their productivity. Knowledge about the microbial communities (pathogens and endosymbionts) of ticks in the United Arab Emirates (UAE) is scarce. Therefore, the aim of the present study was to quantify microbial diversity in H. anatolicum using next-generation sequencing (NGS) technology. METHODS: Hyalomma anatolicum ticks were collected from livestock in the emirates of Abu Dhabi, Dubai and Sharjah in the UAE during 2019. DNA was extracted from 175 male ticks sampled from livestock (n = 78) and subjected to NGS. The 16S rRNA gene was analyzed using the Illumina MiSeq platform to determine the bacterial communities. Principal coordinates analysis (PCA) was performed to identify patterns of diversity in the bacterial communities. RESULTS: Twenty-six bacterial families with high relative abundance were identified, of which the most common were Staphylococcaceae, Francisellaceae, Corynebacteriaceae, Enterobacteriaceae, Moraxellaceae, Bacillaceae, Halomonadaceae, Xanthomonadaceae, Pseudomonadaceae, Enterococcaceae, Actinomycetaceae and Streptococcaceae. The diversity of the microbial communities in terms of richness and evenness was different at the three study locations, with the PCA showing clear clusters separating the microbial communities in ticks collected at Abu Dhabi, Dubai, and Sharjah. The presence of bacterial families harboring pathogenic genera showed that H. anatolicum could pose a potential threat to livestock and food security in the UAE. CONCLUSIONS: The study is the first to document important data on the microbial communities associated with H. anatolicum in the UAE. This knowledge will facilitate a better understanding of the distribution pattern of microbes in livestock ticks in the UAE and, ultimately, will aid in deciphering the relationships between microbes and in the exploration of potential factors towards developing effective management strategies.
Assuntos
Bactérias/genética , Bactérias/isolamento & purificação , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Ixodidae/microbiologia , Gado/parasitologia , Microbiota/genética , Infestações por Carrapato/veterinária , Animais , Bactérias/classificação , Estudos Transversais , Variação Genética , Masculino , Infestações por Carrapato/epidemiologia , Doenças Transmitidas por Carrapatos/epidemiologia , Doenças Transmitidas por Carrapatos/microbiologia , Doenças Transmitidas por Carrapatos/transmissão , Emirados Árabes Unidos/epidemiologiaRESUMO
Ticks (Acari) are ectoparasites of animals that harbor communities of microbes of importance to animal and human health. Microbial communities associated with ticks exhibit temporal patterns of variation in their composition, with different genera dominating at different times of the year. In this study, molecular tools were used to assess the composition of the microbial communities associated with Hyalomma dromdarii. Adult ticks were collected every month for 1 year from 25 camels in the UAE. A total of 12 DNA pools were prepared (one pool for each month). We monitored the microbiota of ticks using high-throughput sequencing of the V3-V4 region of the bacterial 16S rRNA gene. A total of 614 operational taxonomic units were produced through de novo clustering and belonged to 17 phyla, 30 classes, 46 orders, 118 families, and 222 genera. Fifteen bacterial families were found to be the most abundant. The dominant bacterial communities associated with H. dromedarii belonged to the genera Staphylococcus, Bacillus, Francisella, and Corynebacterium, which were reported with high relative abundance from all months. No significant correlation occurred between the abundance of microbial families or genera in H. dromedarii ticks and the ambient temperature. Our findings revealed, for the first time in the UAE, temporal fluctuations of microbial communities in H. dromedarii ticks and provided key insights on the interaction between different microbial groups. Moreover, our results contribute to the current understanding of disease development and allow more investigations for potentially pathogenic microbiota.
RESUMO
Seabirds and some inland waterbirds nest in densely aggregated colonies. Nesting activities for a duration of months could lead to large quantities of guano deposition that affects the soil chemistry, flora and fauna. We assessed the effects of nesting Socotra Cormorants on soil invertebrates on Siniya Island, United Arab Emirates. Artificial substrate traps were set in nesting and non-nesting areas to sample invertebrates both before and after nesting had occurred. Diversity of soil invertebrate taxa decreased significantly in nesting areas compared to non-nesting areas after the commencement of nesting. This indicated that nesting activities had a negative effect on diversity. Among selected taxa, isopods and spiders decreased significantly in response to nesting activities. In contrast, ants were likely affected by habitat while beetles did not change significantly in response to nesting activities, suggesting that their numbers probably fluctuated in relation to seasonality. Ticks increased significantly but only in non-nesting areas. Thus, the impact of nesting varied between taxa depending on life history and seasonality. Our observations reflect the dynamic nature of invertebrate abundance that is affected by seasonality and the hyper-abundance of nesting seabirds.
RESUMO
Ticks and associated tick-borne diseases in livestock remain a major threat to the health of animals and people worldwide. However, in the United Arab Emirates (UAE), very few studies have been conducted on tick-borne microorganisms thus far. The purpose of this cross-sectional DNA-based study was to assess the presence and prevalence of tick-borne Francisella sp., Rickettsia sp., and piroplasmids in ticks infesting livestock, and to estimate their infection rates. A total of 562 tick samples were collected from camels, cows, sheep, and goats in the Emirates of Abu Dhabi, Dubai, and Sharjah from 24 locations. DNA was extracted from ticks and PCR was conducted. We found that Hyalomma dromedarii ticks collected from camels had Francisella sp. (5.81%) and SFG Rickettsia (1.36%), which was 99% similar to Candidatus Rickettsia andeanae and uncultured Rickettsia sp. In addition, Hyalomma anatolicum ticks collected from cows were found to be positive for Theileria annulata (4.55%), whereas H. anatolicum collected from goats were positive for Theileria ovis (10%). The widespread abundance of Francisella of unknown pathogenicity and the presence of Rickettsia are a matter of concern. The discovery of T. ovis from relatively few samples from goats indicates the overall need for more surveillance. Increasing sampling efforts over a wider geographical range within the UAE could reveal the true extent of tick-borne diseases in livestock. Moreover, achieving successful tick-borne disease control requires more research and targeted studies evaluating the pathogenicity and infection rates of many microbial species.
RESUMO
Ticks are important arthropod vectors that serve as reservoirs of pathogens. Rapid urbanization and changes in animal breeding practices could be causing a rise in tick burden on animals. Studies on tick distribution on livestock and tick molecular diversity from the United Arab Emirates (UAE) are limited. The aim of this study was to (i) provide molecular and morphological identification of tick species, (ii) compare tick infestation between different hosts, (iii) compare tick infestation in relation to the sex of the host, and (iv) assess the prevalence of tick species on hosts. A total of 5950 ticks were collected from camels (4803 ticks), cows (651 ticks), goats (219 ticks), and sheep (277 ticks). Ticks were identified based on morphological characters at the species level using taxonomic keys. In addition, Polymerase Chain Reaction (PCR) amplification of the cytochrome oxidase subunit 1 (cox1) and 16S rRNA mitochondrial genes was used to identify ticks. Four species were confirmed based on molecular and morphological characterization, namely, Hyalomma dromedarii, Hyalomma anatolicum, Rhipicephalus sanguineus, and Amblyomma lepidum. Hyalomma dromedarii (94.3%) was the most abundant species, followed by H. anatolicum (32.8%). Camels were heavily infested (94%) with ticks as compared to cows (38%), sheep (37%), and goats (14%). Widespread occurrence of these four tick species in the UAE poses a risk of spreading tick-borne pathogens wherever the conditions of infection prevail.
RESUMO
Ticks are important vectors of an array of viral, bacterial and protozoan pathogens resulting in a wide range of animal and human diseases. There is limited information in the literature about tick species in the Middle East and North Africa (MENA) countries, even though they have suitable climate and vegetation for ticks and their hosts. We reviewed the occurrence of tick species and the pathogens they transmit from the MENA on published papers from 1901-2020. We found taxonomic records of 55 tick species infesting livestock representing the following eight genera: Ornithodoros, Otobius, Amblyomma, Dermacentor, Haemaphysalis, Hyalomma, Ixodes, and Rhipicephalus. In addition, 15 pathogens were recorded causing diseases of significance, with Crimean-Congo hemorrhagic fever, theileriosis, babesiosis and anaplasmosis being widely distributed diseases in the region. In recent decades, there has been increasing trends in disease occurrence and movement associated with global movement of humans and global trade of animals. We suggest that disease control and prevention could be achieved effectively through good integration between public health, veterinary medicine and animal management, and ecological approaches. We recommend further research in the areas of tick ecology and tick born-disease transmission. Furthermore, we suggest evaluation and improvement of disease control policies in the region.
RESUMO
The novel coronavirus disease (COVID-19) that emerged in December 2019 had caused substantial morbidity and mortality at the global level within few months. It affected economies, stopped travel, and isolated individuals and populations around the world. Wildlife, especially bats, serve as reservoirs of coronaviruses from which the variant Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) emerged that causes COVID-19. In this review, we describe the current knowledge on COVID-19 and the significance of wildlife hosts in its emergence. Mammalian and avian coronaviruses have diverse host ranges with distinct lineages of coronaviruses. Recombination and reassortments occur more frequently in mixed-animal markets where diverse viral genotypes intermingle. Human coronaviruses have evolved through gene gains and losses primarily in interfaces where wildlife and humans come in frequent contact. There is a gap in our understanding of bats as reservoirs of coronaviruses and there is a misconception that bats periodically transmit coronaviruses to humans. Future research should investigate bat viral diversity and loads at interfaces between humans and bats. Furthermore, there is an urgent need to evaluate viral strains circulating in mixed animal markets, where the coronaviruses circulated before becoming adapted to humans. We propose and discuss a management intervention plan for COVID-19 and raise questions on the suitability of current containment plans. We anticipate that more virulent coronaviruses could emerge unless proper measures are taken to limit interactions between diverse wildlife and humans in wild animal markets.
RESUMO
The long distant, transcontinental migration of shorebirds entails many well identified costs in terms of time, energy, and direct mortality risk. Injuries from debris or from human structures and activities were observed as the major reasons for the direct mortality of shorebirds during migration worldwide. We recorded injured birds in major coastal wetlands of Kerala, for a period of 15 years from 2005 to 2019. The injured birds were observed in 9 different sites in various districts of Kerala. The highest instances of injuries were observed in Kadalundi-Vallikunnu Community Reserve, the major wintering and stop over site of migrant shorebirds in the west coast of India. During the study period, fifty-eight individuals of shorebirds belonging to four families were found to be injured. The highest proportion of injuries was recorded among the families Scolopacidae and Charadriidae comprising long distance migrant shorebird species and the lowest among Laridae and Ardeidae. We recommend that environmental authorities pay special attention to minimize anthropogenic debris along the flyways used by migratory birds thereby reducing the risk of injuries to some of these species. Proactive measures such as removal of discarded fishing gear or plastic debris from wintering areas as well as stopover areas could greatly reduce injuries in migratory birds arising from anthropogenic sources.
RESUMO
Poyang Lake is situated within the East Asian Flyway, a migratory corridor for waterfowl that also encompasses Guangdong Province, China, the epicenter of highly pathogenic avian influenza (HPAI) H5N1. The lake is the largest freshwater body in China and a significant congregation site for waterfowl; however, surrounding rice fields and poultry grazing have created an overlap with wild waterbirds, a situation conducive to avian influenza transmission. Reports of HPAI H5N1 in healthy wild ducks at Poyang Lake have raised concerns about the potential of resilient free-ranging birds to disseminate the virus. Yet the role wild ducks play in connecting regions of HPAI H5N1 outbreak in Asia is hindered by a lack of information about their migratory ecology. During 2007-08 we marked wild ducks at Poyang Lake with satellite transmitters to examine the location and timing of spring migration and identify any spatiotemporal relationship with HPAI H5N1 outbreaks. Species included the Eurasian wigeon (Anas penelope), northern pintail (Anas acuta), common teal (Anas crecca), falcated teal (Anas falcata), Baikal teal (Anas formosa), mallard (Anas platyrhynchos), garganey (Anas querquedula), and Chinese spotbill (Anas poecilohyncha). These wild ducks (excluding the resident mallard and Chinese spotbill ducks) followed the East Asian Flyway along the coast to breeding areas in northern China, eastern Mongolia, and eastern Russia. None migrated west toward Qinghai Lake (site of the largest wild bird epizootic), thus failing to demonstrate any migratory connection to the Central Asian Flyway. A newly developed Brownian bridge spatial analysis indicated that HPAI H5N1 outbreaks reported in the flyway were related to latitude and poultry density but not to the core migration corridor or to wetland habitats. Also, we found a temporal mismatch between timing of outbreaks and wild duck movements. These analyses depend on complete or representative reporting of outbreaks, but by documenting movements of wild waterfowl, we present ecological knowledge that better informs epidemiological investigations seeking to explain and predict the spread of avian influenza viruses.
Assuntos
Migração Animal , Surtos de Doenças/veterinária , Patos , Virus da Influenza A Subtipo H5N1/isolamento & purificação , Influenza Aviária/epidemiologia , Animais , Ásia/epidemiologia , Influenza Aviária/virologia , Fatores de TempoRESUMO
Small, partially enclosed gulfs are especially vulnerable to coastal pollution. The Arabian Gulf is a shallow, hypersaline, warm gulf with rising levels of pollution caused by rapid development and industrialization. We measured 19 trace elements in the gastrointestinal tract, liver and muscle of Indian oil sardines (Sardinella longiceps) from three sites from the United Arab Emirates in the southern Arabian Gulf. Concentrations of cadmium, chromium, copper and zinc exceeded international maximum permissible limits (MPL) in all three tissues in most sites. High concentrations in muscle raises concerns about the risk to humans, as muscles are widely consumed by humans. Discriminant Function Analysis showed that the three study sites (Sharjah, Ajman and Umm Al Quwain) could be discriminated based on a combination of elements. Improved monitoring of pollutants is needed to ascertain the concentration of pollutants in species at different trophic levels. We recommend better control measures to reduce the discharge of pollutants into this fragile marine ecosystem.
Assuntos
Metais Pesados , Oligoelementos , Poluentes Químicos da Água , Animais , Bioacumulação , Ecossistema , Monitoramento Ambiental , Humanos , Metais Pesados/análise , Oligoelementos/análise , Emirados Árabes Unidos , Poluentes Químicos da Água/análiseRESUMO
Pollution in the Arabian Gulf has risen in recent decades due to rapid development in the region. We studied 21 elements in the liver, gastrointestinal (GI) tract and muscles of the Indian anchovy (Stolephorus indicus) to characterize bioaccumulation in this abundant forage fish. Mean concentrations (µg/g wet weight) of elements ranged as follows: Cd: 0.1-8.0; Cr: 0.1-24.0; Cu: 1.2-24.0; Ni: 0.3-76.5; Ca: 1237.0-15,270.0; S: 2966.0-7467.0; Zn: 7.1-247.0; V: 0.1-27.0; Hg: 0.04-0.18 and Sr: 8.1-191.0. Zn, Cu, Cr, and Cd in the tissues exceeded the maximum permissible limit recommended by FAO, WHO and EC. We suggest that bioaccumulation in fish could be a hazard for human consumption. Therefore, further monitoring is needed to better characterize pollutant levels in fish of higher trophic levels in the Arabian Gulf.
Assuntos
Metais Pesados , Poluentes Químicos da Água , Animais , Bioacumulação , Monitoramento Ambiental , Peixes , Humanos , Emirados Árabes UnidosRESUMO
Raorchestes is a speciose genus of bush frogs with high diversity occurring in the Western Ghats of India. Relatively fewer species have been recorded across India, through Bangladesh, southern China, into Vietnam and Peninsular Malaysia. Many bush frogs are morphologically cryptic and therefore remain undescribed. Here, a new species, Raorchestes rezakhani sp. nov., is described from northeastern Bangladesh based on morphological characters, genetics, and bioacoustics. The 16S rRNA gene distinguished this species from 48 known species of this genus. Bayesian Inference and Maximum Likelihood analyses indicated that the new species was most similar to R. tuberohumerus, a species found in the Western Ghats, and to R. gryllus, a species found in Vietnam. Bioacoustics indicated that their calls were similar in pattern to most Raorchestes species, although number of pulses, duration of pulses, pulse intervals and amplitude differentiated it from a few other species. It is suggested that northeastern India, Bangladesh, northern Myanmar, and southern China represent important, relatively unexplored areas that could yield additional species of Raorchestes. Since many remaining habitat patches in Bangladesh are under severe threat from deforestation, efforts should be made to protect these last patches from further degradation.