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Avaliação de índices ecológicos de peixes capturados em curral de pesca na Amazônia Oriental, Brasil

2026-07-30T18:29:14Z

Título: Avaliação de índices ecológicos de peixes capturados em curral de pesca na Amazônia Oriental, Brasil Abstact: This study evaluated the diversity and abundance of the ichthyofauna captured by artisanal fish corrals in Mangue Seco, Raposa (Maranhão), considering seasonality (dry and rainy seasons of 2024/2025). A total of 47 species (2,545 individuals) were recorded, with richness and abundance significantly higher during the dry season—strongly correlated with higher salinity and conductivity. The catch included threatened species (such as *Aetobatus narinari*, Endangered) and data-deficient species, highlighting fishing pressure on sensitive populations. Ecological indices revealed a moderately diverse community with low dominance. The results emphasize the decisive influence of seasonal environmental factors on community structure and the need to incorporate ecological monitoring into the sustainable management of this traditional fishery.

Sorovariedades de Leptospira sp. circulantes em duas espécies de peixes neotropicais em área lacustre maranhense, Brasil

2026-07-22T19:39:54Z

Título: Sorovariedades de Leptospira sp. circulantes em duas espécies de peixes neotropicais em área lacustre maranhense, Brasil Abstact: Leptospirosis is a zoonosis with a cosmopolitan distribution whose etiological agent can infect different animal species and accidentally infect humans. Despite the wide variety of hosts, there is a scarcity of studies on the occurrence of the disease in species living in aquatic habitats. In this sense, the objective was to diagnose the serovarities of Leptospira sp. circulating in two species of neotropical fish from the quilombola area of Maranhão. To this end, the study was divided into three stages: (i) bibliographical survey on the topic under study, with a search in the databases Pubmed, SciELO, Periódicos Capes, Catalog of Theses and Dissertations Capes, Theses and Dissertations of Postgraduate Programs graduation from the state of Maranhão, in addition to websites of Official Bodies, using Boolean connectors and signals as search strategies, according to the methodology of each database and also inclusion and exclusion criteria; (ii) field activity with the measurement of abiotic parameters (temperature, hydrogen potential and salinity) of the water in the fish capture environment, using a multiparameter instrument and capture of 42 fish specimens, 21 of which were Hoplerythrinus unitaeniatus (jeju) and 21 Cichlasoma bimaculatum (black acará). The captured fish were transported alive in isothermal boxes with water from the capture site, equipped with equipment to oxygenate the water, to the State University of Maranhão. In a laboratory environment, blood samples were collected by channeling branchial veins. The sera obtained were tested for anti-leptospira agglutinins against 25 serovars of the Leptospira sp. complex. using the microscopic seroagglutination technique; and, (iii) preparation of a guide on health and the environment in quilombola communities. As results of the first stage of the study, the bacteria identified in the bibliographical survey were total and thermotolerant coliforms, Escherichia coli, Salmonella spp., Aeromonas cavie, A. hydrophila, A. veroni biovar veron, A. schubertii, A. trota, Staphylococcus sp. and positive coagulase, Citrobacter sp. and Serratia odirifera. None of the bacteria identified in this survey are included in the list of notifiable diseases of the Ministry of Agriculture, Livestock and Supply and the World Organization for Animal Health. As for the second stage of the study, the sampled environment found characteristics favorable to the survival of Leptospira sp. such as the low speed of the water; pH of 7.31; and, temperatures of 28.3 °C. The total occurrence of anti-Leptospira agglutinins in the study was 80.95% (n=34/42) with titers ranging from 1:100 to 1:400. The serovarities of the Leptospira sp. The most frequent were: Pomona, Hebdomadis, Butembo, Copenhageni, Cynopteri, Panama, Sentot, Bratislava, Icteriohaemorragiae, Pomona variant Bubalinos, Pyrogenes, Whitcombi. Leptospirosis, an infectious disease documented worldwide in several animal species and in humans, infects native fish H. unitaeniatus and C. bimaculatum with high percentages of occurrence. Health education actions are needed with the quilombola community about the risks of using water and fishing resources from the flooded environment studied. It is also necessary to investigate the sources of infection for fish and apply appropriate measures to prevent leptospirosis in this geographic area. It is expected that the results obtained in this study and the guidance prepared in the third part stage of the study can help in the discussion and development of control strategies for leptospirosis in quilombola areas whose economy is based, above all, on artisanal fishing.

Biomarcadores histológicos em Lutjanus chrysurus BLOCH (1791) capturados na ilha de Itamaracá afetada pelo derramamento de óleo no estado de Pernambuco, Brasil

2026-07-22T19:43:45Z

Título: Biomarcadores histológicos em Lutjanus chrysurus BLOCH (1791) capturados na ilha de Itamaracá afetada pelo derramamento de óleo no estado de Pernambuco, Brasil Abstact: This study aimed to analyze histological biomarkers in gills, liver, kidney and gonad in the species Lutjanus chrysurus in one of the stretches most affected by the oil spill in the state of Pernambuco. The fish were acquired by purchasing trade on the island of Itamaracá, Pernambuco. In the laboratory, biometrics of each specimen and dissection for removal and fixation gills, kidneys, gonads and liver was carried out when they were fixed in 10% formalin for 24 hours. Then the gills were decalcified for 9 hours. The tissue samples were submitted to the standard histological technique, when they were dehydrated in crescents series of alcohols, cleared in xylene, impregnated and embedded in paraffin in then cross-sections of 5 micrometers thick were stained with Hematoxylin and Eosin (HE) and slides were analyzed under a light microscope. Biometric data of the fish in the study area were expressed as means and standard deviations. To verify normality, the Shapiro-Wilk test) was used and for homoscedasticity we used the Levene test. Student's t test was used to verify possible differences between means. Student's t test was used to compare the data of branchial and hepatic lesions found. The data showed significant lesions in gill and liver in fish from the study area. The main injuries found for the gills were fusion, hyperplasia, necrosis and lamellar disorganization, the statistical data show that there are significant differences only for the lamellar disorganization injury. The most observed liver lesions were fibrosis, necrosis and steatosis for sample collection 1, while for sample collection 2 the most frequent lesions were necrosis, center melanomacrophages (MMCs) and differentiating cells. The t-test showed that differences only for fibrosis and necrosis lesions (p<0.05). For kidney tissue changes observed were spacing of the capillary endothelium, increased lumen tubular lumen, Bowman's capsule enlargement, necrosis, CMMs, tubular lumen occlusion, and blood vessel dilation. For the gonads, the changes observed were CMMs, necrosis and atretic follicle. The biometrics indicated for the fish that there were no differences significant between sexes (p>0.05). The study indicated that biological responses alterations (branchial, hepatic, renal and gonodal alterations) prove the existence of that these animals are submitted to levels of stress that are inhibiting the biological activities of the fish.

Influência da atividade pesqueira na contaminação por plásticos em peixes do Lago Viana, Área de Proteção Ambiental (APA) da Baixada Maranhense

2026-07-14T14:39:31Z

Título: Influência da atividade pesqueira na contaminação por plásticos em peixes do Lago Viana, Área de Proteção Ambiental (APA) da Baixada Maranhense Abstact: Plastic pollution in aquatic ecosystems poses a challenge to biodiversity conservation and food security, especially in regions where artisanal fishing is a socially relevant activity. This study evaluated the occurrence and characterized plastic particles in two biomonitor fish species, Pygocentrus nattereri and Hypostomus plecostomus, collected in Lake Viana, Maranhão, during the dry and rainy seasons. Biometric data (weight, total length, and standard length) were recorded, and stomach contents were analyzed to identify plastic particles according to type, color, size, and polymeric composition. Statistical analyses included comparisons between seasonal periods and species, as well as correlations between biometric variables and the number of ingested particles. A total of 79 plastic particles were identified, with an absolute dominance of fibers (94–100%) and a smaller proportion of fragments. The most frequent colors were transparent and blue, varying according to species and season. Infrared spectroscopy revealed a predominance of polyamide (51.9%) and rayon (24.1%), followed by polypropylene, polyester, polystyrene, polyethylene, and polyurethane. No significant differences were found in plastic ingestion between species or seasonal periods. The ecotoxicological risk assessment, based on chemical composition and polymer hazard categories, indicated that most detected polymers are classified as moderate risk, although high- risk materials such as polystyrene and polyurethane were also present. The results indicate that exposure to plastic particles in Lake Viana is more strongly influenced by the environmental availability and persistence of plastic debris than by species-specific traits, highlighting the need for integrated mitigation strategies. This study contributes to advancing knowledge on plastic pollution in tropical freshwater environments and aligns with the goals of the 2030 Agenda, particularly Sustainable Development Goals 3, 12, and 14.