What are the global patterns of microplastic ingestion by fish? A scientometric review.

The billions of tons of plastic released into the environment mostly fragment into smaller particles that reach rivers and oceans, posing toxicity risks to aquatic organisms. As fish serve as excellent environmental indicator organisms, this study aims to comprehensively review and quantify published data regarding the abundance of microplastics (MPs) ingested by fish through scientometric analysis. Systematic analysis reveals that global aquatic ecosystems are contaminated by MPs, with the characteristics of these contaminants stemming from inadequate disposal management practices. The abundance of MPs was recorded in several fish species, notably Cyprinus carpio in natural environments and Danio rerio in controlled environments. According to the surveyed studies, laboratory experiments do not accurately represent the conditions found in natural environments. The results suggest that, in natural environments, the predominant colors of MPs are blue, black, and red. Fibers emerged as the most prevalent type, with polyethylene (PE) and polypropylene (PP) being the most frequently identified chemical compositions. On the other hand, laboratory studies showed that the spheres and fragments ingested were predominantly polystyrene (PS) green, followed by the colors blue and red. This discrepancy complicates drawing accurate conclusions regarding the actual effects of plastic particles on aquatic biota. Given the enduring presence of plastic in the environment, it is imperative to consider and implement environmental monitoring for effective, long-term management.

BDE-99 (2,2',4,4',5 - pentain polybrominated diphenyl ether) induces toxic effects in Oreochromis niloticus after sub-chronic and oral exposure.

PBDEs are toxic, lipophilic, hydrophobic, and persistent artificial chemicals, characterized by high physical and chemical stability. Although PBDEs are known to disturb hormone signaling, many effects of 2,2',4,4',5 - pentain polybrominated diphenyl ethers (BDE-99) in fish remain unclear. The current study investigates the effects of BDE-99 in Oreochromis niloticus where sixty-four juvenile fish were orally exposed to 0.294, 2.94, 29.4 ng g-1 of BDE-99, every 10 days, during 80 days. The results showed histopathological findings in liver and kidney, increasing acetylcholinesterase activity in muscle, disturbs in the antioxidant system in liver and brain and decreasing the plasmatic levels of vitellogenin in females. According to multivariate analysis (IBR), the higher doses are related to the interaction of oxidative and non-oxidative enzymes. The present study provided evidence of deleterious effects after sub-chronic exposure of BDE 99 to O. niloticus, increasing the knowledge about its risk of exposure in fish.

Effects of trophic 2,2', 4,4'-tetrabromodiphenyl ether (BDE-47) exposure in Oreochromis niloticus: A multiple biomarkers analysis.

Polybrominated diphenyl esters are emerging environmental contaminants with few toxicological data, being a concern for the scientific community. This study evaluated the effects of BDE-47 on the health of Oreochromis niloticus fish. The animals were exposed to three doses of BDE-47 (0, 0.253, 2.53, 25.3 ng g-1) every 10 days, for 80 days. The BDE-47 affected the hepatosomatic and gonadosomatic index in female and the condition factor by intermediate dose in both sexes. The levels of estradiol decreased and the T4 are increased, but the vitellogenin production was not modulated in male individuals. Changes in AChE, GST, LPO and histopathology were observed while the integrated biomarker response index suggests that the lowest dose of BDE-47 compromised the activity of antioxidant enzymes. The oral exposure to BDE-47 in environmental concentrations is toxic to O. niloticus and the use of multiple biomarkers is an attribution in ecotoxicology studies and biomonitoring programs.

Cell damage induced by polybrominated diphenyl ethers on Chironomus sancticaroli (Diptera: Chironomidae)

Abstract Histological effects of polybrominated diphenyl ethers (PBDEs) were observed in Chironomus sancticaroli larvae which underwent acute exposure. 2,2′,4-triBDE (BDE-17), 2,2′,4,4′-tetraBDE (BDE-47) and 2,2′,4,4′,5-pentaBDE (BDE-99) were evaluated at 0.5, 2.0 and 20 μg L-1. Cytoplasm vacuolisation of oenocytes was observed in the larvae exposed to BDE-17 and BDE-47. Cuénot cells were disrupted at the brush border as an effect of the three evaluated congeners highlighting BDE-47 at 2.0 μg L-1; 60% of larvae displayed this disruption. The midgut showed changes in the morphology of apex cells located next to the lumen of region I exposed to BDE-17 and BDE-47, while BDE-99 induced a narrowing of the lumen diameter. Significant cytoplasm vacuolisation of the larvae exposed to BDE-47 and BDE-99 was observed in region II of the midgut. Salivary glands showed acidophilic granules in the cytoplasm exposed to BDE-17 and BDE-47. The results showed that the tissues of C. sancticaroli were sensitive to flame retardants; these histopathologies can compromise the health and physiology of this organism, highlighting the concern with the presence of PBDEs in freshwater sediments.

Effect of long-term thermal challenge on the Antarctic notothenioid Notothenia rossii.

The thermal stability of the Antarctic Ocean raises questions concerning the metabolic plasticity of Antarctic notothenioids to changes in the environmental temperature. In this study, Notothenia rossii survived 90 days at 8 °C, and their condition factor level was maintained. However, their hepatosomatic (0.29×) index decreased, indicating a decrease in nutrient storage as a result of changes in the energy demands to support survival. At 8 °C, the plasma calcium, magnesium, cholesterol, and triglyceride concentrations decreased, whereas the glucose (1.91×) and albumin (1.26×) concentrations increased. The main energy substrate of the fish changed from lipids to glucose due to a marked increase in lactate dehydrogenase activity, as demonstrated by an increase in anaerobic metabolism. Moreover, malate dehydrogenase activity increased in all tissues, suggesting that fish acclimated at 8 °C exhibit enhanced gluconeogenesis. The aerobic demand increased only in the liver due to an increase (2.23×) in citrate synthase activity. Decreases in the activities of superoxide dismutase, catalase, and glutathione-S-transferase to levels that are most likely sufficient at 8 °C were observed, establishing a new physiological activity range for antioxidant defense. Our findings indicate that N. rossii has some compensatory mechanisms that enabled its long-term survival at 8 °C.

Age and growth of Zapteryx brevirostris (Elasmobranchii: Rhinobatidae) in southern Brazil

Age and growth studies are fundamental to successful fisheries management. Zapteryx brevirostris (Müller & Henle, 1841) is distributed off the Brazilian continental shelf and this species is assessed as "Vulnerable" in the Red List of the International Union for the Conservation of Nature (IUCN). Thus, the objective of this study was to present previously unknown information about the age and growth of Z. brevirostris that can be used for its management, conservation, and fisheries. A total of 162 specimens were sampled, with total lengths (TL) varying between 35.7 cm and 56 cm. The vertebrae were embedded in resin, sectioned in cuts with 0.5 mm thickness and the growth bands of the vertebrae were read under a light microscope. In the studied area, Z. brevirostris ages were estimated from 4 to 10 years according to vertebrae patterns. The species reaches its maximum asymptotic size (Linf) around 56 cm (56 cm for females and 50.37 cm for males). This is the first estimate of age and growth for a species of the Zapteryx genus, and the results support the hypothesis that this ray requires future management conservation, particularly due to its slow growth rate and consequent susceptibility to overexploitation.(AU)

Estudos de idade e crescimento são fundamentais para o sucesso da gestão pesqueira. Zapteryx brevirostris (Müller & Henle, 1841) distribui-se pela plataforma continental brasileira, sendo classificada como "Vulnerável" no livro vermelho da IUCN (International Union for the Conservation of Nature). Assim, o objetivo deste estudo foi apresentar informações previamente desconhecidas sobre a idade e o crescimento de Z. brevirostris que podem ser utilizados para sua gestão, conservação e pescas. No total foram amostrados 162 espécimes, com comprimento total (CT) variando de 35.7 cm a 56 cm. As vértebras foram incluídas em resina e seccionadas num corte com cerca de 0.5 mm de espessura, e as bandas de crescimento das vértebras foram lidas com microscópio de luz transmitida branca. Na área estudada, Z. brevirostris possui idades estimadas entre os 4 a 10 anos de idade, de acordo com seu padrão de vértebras. A espécie atinge seu Linf (comprimento máximo assintótico) em torno dos 56 cm (56 cm para fêmeas e 50.37 cm para machos). Essa é a primeira estimativa dos parâmetros de idade e crescimento para uma espécie do gênero Zapteryx, e os resultados obtidos corroboram a hipótese de que a espécie requer uma gestão de conservação adequada, devido sobretudo à sua lenta taxa de crescimento e consequente suscetibilidade à sobre-exploração.(AU)

Paracetamol causes endocrine disruption and hepatotoxicity in male fish Rhamdia quelen after subchronic exposure.

Paracetamol is one of the most widely sold non-prescription drugs. This study aimed to evaluate the effects of the paracetamol on reproductive, biochemical, genetic, histopathological and hematogical biomarkers by waterborne exposure. Male fish of Rhamdia quelen were exposed to environmental concentrations of paracetamol (0, 0.25, 2.5µg/L) in a semi-static bioassay for 21days. Hemoglobin and hematocrit were reduced upon exposure to 0.25µg/L of paracetamol. Leukocytes and thrombocytes increased after paracetamol exposure. Paracetamol reduced testosterone levels in all exposed groups and increased estradiol levels at higher concentration. Serotonin and dopamine levels increased at exposure to 0.25µg/L. Paracetamol also caused protein carbonyls and increased SOD activity in fish exposed to 2.5µg/L and in addition led to an inhibition of EROD and GST activities in both concentrations. Hepatic genotoxicity occurred at the 0.25µg/L concentration. Hepatic tissues of exposed fish showed mild blood congestion and leucocytes infiltration. The results showed that paracetamol disrupted the hypothalamic-pituitary-gonadal axis, changed hematological parameters and caused hepatotoxicity in Rhamdia quelen. The findings suggest that this drug merits attention relative to its potential endocrine disrupter effect and hepatotoxicity, even at concentrations found in the aquatic environment.

Effects of environmentally relevant concentrations of the anti-inflammatory drug diclofenac in freshwater fish Rhamdia quelen.

The presence of pharmaceuticals in the aquatic environment and its impact on humans and the ecosystem are emerging issues in environmental health. This study evaluated the potential biochemical, genetic and reproductive effects of the diclofenac by waterborne exposure, in a semi-static bioassay for 21 days. The fish Rhamdia quelen were exposed to environmental concentrations of diclofenac (0, 0.2, 2 and 20µg/L). The results showed that in the liver, diclofenac reduced the catalase and ethoxyresorufin- O- deethylase activities in fish exposed to 2µg/L, and superoxide dismutase in all exposed groups. The levels of reduced glutathione and glutathione S-transferase (GST) activity increased at all tested concentrations. Lipid peroxidation (LPO) was reduced in the groups exposed to 0.2 and 20µg/L of diclofenac, but there was no protein oxidation. In the testis, the concentration of 0.2µg/L caused major changes as inhibition of SOD, glutathione peroxidase and GST activities and also LPO decrease. Diclofenac was not genotoxic and not altered plasma testosterone and estradiol levels and testicular morphology. In brain, there was a reduction of dopamine and its metabolite DOPAC (3, 4-dihydroxyphenylacetic acid) in exposure to diclofenac, but this not disrupted the hypothalamic-pituitary-gonadal axis.

Morpho-histological characterization of immature of the bioindicator midge Chironomus sancticaroli Strixino and Strixino (Diptera, Chironomidae)

ABSTRACTChironomidae immature are used as bioindicators of sediment quality in aquatic ecosystems and ecotoxicological assays. Histological descriptions for this family are outdated and limited and there are no studies with Neotropical species. The aim of this study was to describe the tissue architecture of several organs of the larva of Chironomus sancticaroli. For the description of the histological pattern, the larvae were fixed in Duboscq solution for insects at 56 °C, followed by routine histologic processing, infiltration in paraffin, and the sections were stained with Hematoxylin–Eosin. After examining the slides, the tube digestive, salivary gland, excretory, nervous, endocrine, circulatory, and integumentary systems and fat body were histologically characterized. The histology allows evaluation of cell morphology, and for being not expensive and easily accessible can be routinely used in biomonitoring. In addition, is a useful tool in ecotoxicological assays and allow to evaluate biomarkers at tissue and cell levels.

In situ assessment of a neotropical fish to evaluate pollution in a river receiving agricultural and urban wastewater.

We aimed to assess the quality of a midsize river that receives agricultural and urban wastewater. Nuclear abnormalities (NA), comet assays of blood and gills, and gill histopathology were evaluated in fish Astyanax aff. paranae during the summer and winter 2011 at three sites in Paraná State, Brazil: (1) a biological reserve (Rebio-reference area); (2) an agricultural site; (3) a downstream site that accumulates agricultural and urban effluents. We found the highest effects of pollutants in fish at the downstream site during the summer. The agricultural site showed an intermediate damage rate, and fish at Rebio generally had the least damage, with the exception of NA. Despite conflicting results from the biomarkers used, we observed an increase in damage associated with the accumulation of pollutants. Pesticides are probable xenobiotics in the agricultural area. Additionally, metals and substances such as pharmaceuticals and ammonia may be present at the downstream site.

Fishes of Paranaguá Estuarine Complex, South West Atlantic / Peixes do Complexo Estuarino de Paranaguá, Atlântico Sul Oeste

The objective of this work was to present an updated checklist of the currently known fishes in the Paranaguá Estuarine Complex (PEC) and provides comments on conservation status for the treated species. We used a large dataset derived from a pool of studies which have been conducted within there along the last 30 years. Each study was based on monthly samplings and conducted in several estuarine habitat; thus, the pool covers practically all estuarine habitats and takes into account the seasonal cycle in the system. The PEC ichthyofauna represents a mixture between that fauna typical from the tropical Brazilian coast and that with affinities of temperate Argentinean and Uruguayan zones. The PEC harbors a rich fish fauna of 213 species, inserted in the families that are common along the Brazilian coast. Only a minor part (8%) of the PEC fish fauna was evaluated as regards the conservation status, mostly because of the lack of basic biological and ecological information for most species. Despite part of the among-estuaries differences are due to different and incomplete sampling efforts, the richness in the PEC is surprisingly higher than other systems in Brazil and around world, which emphasize the importance of the region for global biodiversity conservation.

O objetivo deste trabalho é apresentar uma lista de espécies atualizada a partir do conhecimento atual dos peixes no Complexo Estuarino de Paranaguá (CEP), com comentários sobre o status de conservação das espécies. Nós utilizamos um grande conjunto de dados derivados de diversos estudos conduzidos na região ao longo dos últimos 30 anos. Cada estudo foi baseado em amostragens mensais realizadas em diferentes habitats estuarinos. Dessa forma, os dados abrangem praticamente todos os habitats estuarinos e leva em conta o ciclo sazonal no sistema. A ictiofauna do CEP representa uma mistura entre a fauna típica da costa tropical brasileira e da fauna com afinidade com as zonas temperadas argentinas e uruguaias. O CEP abriga 213 espécies, inseridas em famílias que são comuns ao longo da costa brasileira. Apenas uma pequena parte (8%) das espécies foi avaliada quanto ao status de conservação, principalmente por causa da falta de informações biológicas e ecológicas básicas para a maioria das espécies. Apesar de parte das diferenças entre estuários ser devido a diferentes e incompletos esforços amostrais, a riqueza do CEP é surpreendentemente elevada em comparação com outros sistemas do Brasil e ao redor do mundo, o que enfatiza a importância da região para a conservação da biodiversidade global.

Reproductive biology of the flatfish Etropus crossotus (Pleuronectiformes: Paralichthyidae) in the Paranaguá Estuarine Complex, Paraná State, subtropical region of Brazil

The present work studied the reproduction of the flatfish Etropus crossotus in the Paranaguá Estuarine Complex, Paraná State, subtropical region of Brazil. Monthly collections of biological material occurred from October 2008 to October 2009, at seven sampling sites, through ten-minute otter trawl surveys in the shallow infralittoral areas of the estuary. Temperature, water salinity, photoperiod, and rainfall data were also recorded. Ovarian histology was used to: 1 - describe ovarian development microscopically, 2 - make the quantitative analyses of both sexes more precise. The maturation curve, the frequency of gonadal maturation states and the condition factor verified that the reproductive period occurred from October to January. The frequency of young and adult individuals established that the recruitment period occurred in January and February. There were no significant differences in the sex ratio during the study period. The studied species completes its entire life cycle in an estuary and its reproduction is well-synchronized with the temporal variations implicit in subtropical regions.

O presente trabalho estudou a reprodução do linguado Etropus crossotus no complexo estuarino de Paranaguá, região subtropical do Brasil. Coletas mensais de material biológico ocorreram de outubro de 2008 a outubro de 2009, em sete pontos amostrais, através da realização de dez minutos de arrasto de porta no infralitoral raso do estuário. Ainda, foram obtidos dados de temperatura e salinidade da água, fotoperíodo e pluviosidade para caracterização do ambiente. A histologia de ovário foi utilizada para: 1- descrever microscopicamente o desenvolvimento ovariano, 2- conferir precisão aos resultados das análises quantitativas de ambos os sexos. Através da curva de maturação, da frequência de estádios de maturação gonadal e do fator de condição verificou-se que o período reprodutivo ocorreu de outubro a janeiro. A partir da frequência de indivíduos jovens e adultos constatou-se que o período de recrutamento ocorreu em janeiro e fevereiro. Não se obteve diferenças significativas na proporção sexual ao longo do período estudado. A espécie estudada completa todo o seu ciclo de vida em estuários e sua reprodução mostrou-se bem sincronizado às variações temporais implícitas em regiões subtropicais.

Reproductive tactics used by the Lambari Astyanax aff. fasciatus in three water supply reservoirs in the same geographic region of the upper Iguaçu River

The species Astyanax aff. fasciatus was investigated as regards differences in reproductive tactics in three reservoirs with different ages (Iraí, Piraquara and Passaúna) located in the same geographic region. The biological material was obtained through monthly collections carried out from july/2006 to june/2007. The average value of the gonadosomatic index (GSI) in Passaúna reservoir was significantly higher in relation to the values obtained in the other reservoirs. Spawning was total in Iraí reservoir and partial in the others. Allometric growth of the species was negative in Iraí reservoir and positive in the others. The highest condition factor value was estimated in Iraí reservoir, followed by Piraquara and Passaúna reservoirs, respectively. Females predominated in all of the reservoirs during the study period. The sex ratio per length class showed, for the three reservoirs, the predominance of males in the smaller length classes. These results verified that the species uses distinct reproductive tactics in the analyzed reservoirs and that these tactics seem to reflect the degree of stabilization of each environment.

A espécie Astyanax aff. fasciatus foi investigada quanto a diferenças nas táticas reprodutivas em três reservatórios de diferentes idades (Iraí, Piraquara e Passaúna), localizados em uma mesma região geográfica. O material biológico foi obtido através de coletas mensais realizadas de julho/2006 a junho/2007. Evidenciou-se maior atividade reprodutiva nos períodos mais quentes do ano. O valor médio do IGS no reservatório do Passaúna apresentou-se significativamente maior em relação aos valores obtidos nos outros reservatórios. A desova foi caracterizada do tipo total no reservatório do Iraí e do tipo parcelada nos outros reservatórios. A espécie apresentou crescimento alométrico negativo no reservatório do Iraí e alométrico positivo nos reservatórios do Passaúna e Piraquara. O maior valor do fator de condição foi estimado no reservatório do Iraí, seguido pelos reservatórios do Piraquara e Passaúna, respectivamente. Durante o período de estudo as fêmeas predominaram sobre os machos em todos os reservatórios. A análise da proporção sexual por classe de comprimento evidenciou, para os três reservatórios, o predomínio de machos nas menores classes de comprimento. Através destes resultados constatou-se que a espécie utiliza táticas reprodutivas distintas para os reservatórios analisados e que estas táticas parecem refletir o grau de estabilização de cada ambiente.

Environmental influences on the spatial and temporal distribution of the puffer fish Sphoeroides greeleyi and Sphoeroides testudineus in a Brazilian subtropical estuary

The spatial and temporal distribution of Sphoeroides greeleyi and Sphoeroides testudineus were established from collections (biological material and environmental data) conducted on a monthly basis from May 2000 to April 2001 in intertidal areas along the north-south axis of the estuarine complex of Paranaguá, Paraná State. In addition to characterizing a north-south spatial gradient, which fluctuates seasonally, the variation in the abiotic factors made possible the division of the estuary into three regions: north, central and south. Spatially, it was found that the number of individuals declines significantly for both species in the north-south direction of the estuary. Moreover, significant differences were found in the size of individuals across the estuarine regions. The largest S. greeleyi individuals were caught in the north, as well as the smallest S. testudineus individuals. The catches with the highest numbers of puffer fish occurred from late spring to early autumn, coinciding with the occurrence of specimens of smaller size and lower mean body mass. The results indicate that spatial and temporal variations in the environment impact the distribution patterns of both puffer fish species, suggesting that the co-occurrence of closely related species functions as a modulating factor in that distribution.

A distribuição espacial e temporal de Sphoeroides greeleyi e Sphoeroides testudineus foram estabelecidas a partir de coletas (material biológico e dados ambientais) realizadas mensalmente de maio/2000 a abril/2001 em áreas intertidais, no eixo norte-sul, do complexo estuarino de Paranaguá, Estado do Paraná. A variação dos fatores abióticos coletados, além de caracterizar um gradiente espacial, no sentido norte-sul, que varia sazonalmente, possibilitou a divisão do estuário em três regiões: norte, central e sul. Espacialmente, verificou-se para ambas as espécies que o número de indivíduos decresce, significativamente, no sentido norte-sul estuarino. Ainda, foram encontradas diferenças significativas no porte dos indivíduos entre as regiões do estuário, no norte ocorreram os maiores indivíduos de S. greeleyi e os menores de S. testudineus. As maiores capturas dos baiacus ocorreram do final da primavera ao início do outono, coincidindo com a ocorrência de exemplares de menor tamanho e de menor massa corporal média. Os resultados indicam que as variações espaciais e temporais do ambiente afetam os padrões de distribuição de ambas as espécies de baiacus, sugerindo que a co-ocorrência de espécies aparentadas age como um fator modulador nesta distribuição.