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Biomarcadores de efeito e parasitológicos em peixes nativos para avaliação ambiental de dois lagos da baixada maranhense, Amazônia oriental

2024-01-29T00:00:00Z

Título: Biomarcadores de efeito e parasitológicos em peixes nativos para avaliação ambiental de dois lagos da baixada maranhense, Amazônia oriental Abstact: The biomonitoring of environmental quality is essential for evaluating the relationship between pollutants, organisms, and their effects, which can indicate the association of environmental degradation with parasitic activity in fish, affecting the epidemiological triad (host-parasite-environment). This can result in economic losses in fishing, food security issues, and public health risks due to the zoonotic potential of some parasites and the presence of pollutants. Thus, biomarkers of effect and parasitological parameters were evaluated in three species of native fish from the Açu and Viana lakes in the Baixada Maranhense, Eastern Amazon, during two seasonal periods. Microbiological, physical, and chemical data from the surface waters of the lakes were measured at three sampling points (P1, P2, and P3). Additionally, water, sediment, and fish muscle samples were collected for microbiological analyses, total coliform quantification, Escherichia coli, and trace elements. A total of 240 fish of the species Hoplias malabaricus, Pygocentrus nattereri, and Prochilodus lacustris were collected from the lakes for micronucleus (MN) testing, determination of the Histological Alteration Index (HAI) in gills and liver, and parasitic fauna collection. Water parameters pH, dissolved oxygen (OD), and E. coli showed values outside the recommended limits by CONAMA 357/2005 and 430/2011 regulations. Total coliforms and E. coli were found in all water samples, with higher values in Lake Açu in both seasonal periods. Metals Al>Fe>Cu>Mn>Pb>Hg>Se and Al>Fe>Mn>Cu>Pb>Hg>Se were found in water, sediment, and fish muscle, with higher values during the dry season. There was a significant difference (p<0.05) for MNi, higher during the dry season for both lakes and all three species, being 0.8% for H. malabaricus, 0.4% for P. nattereri, and 0.6% for P. lacustris. Erythrocytic nuclear alterations were more significant during the rainy season, especially notching. There was a correlation between the metals found in water and sediment samples with erythrocytic nuclear alterations, indicating that metal concentrations in these ecosystems can affect fish health. Histological alterations in the gills and livers of fish showed higher HAI values during the dry season. There was a statistical difference in gills for P. nattereri (p<0,0001) in Lake Açu and in the liver for P. lacustris (p<0,0001) and P. nattereri (p=0.03) in Lake Açu and P. nattereri (p=0,049) in Lake Viana. Parasites Contracaecum sp. and Procamallanus sp. were found in the internal cavities, liver, and fat region of the fish, isopod Braga patagonica in the gill cavities, pelvic and lateral fins, as well as Trypanosoma sp., Myxobolus sp., and Haemogregarina sp. in the fish blood. In summary, this study highlights the importance of environmental monitoring of lakes and fish health to identify risks to the population and the ecosystem. The data will support future research and protective measures, emphasizing the need to understand and conserve the lacustrine environments of the Baixada Maranhense Protected Area

Diversidade das linhagens de siris do gênero Callinectes (STIMPSON, 1860) no Golfão Maranhense a partir dos marcadores de DNA mitocondrial e nuclear

2025-06-27T00:00:00Z

Título: Diversidade das linhagens de siris do gênero Callinectes (STIMPSON, 1860) no Golfão Maranhense a partir dos marcadores de DNA mitocondrial e nuclear Abstact: Crabs belonging to the genus Callinectes Stimpson, 1860 are an ecologically and socioeconomically significant group of benthic organisms. Knowledge of the phylogenetic relationships and diversity of their lineages is an important parameter for their conservation and management. Thus, the objective of this work was to describe the diversity of crab lineages of the genus Callinectes present at the eastern limit of the Brazilian Amazonian coast. The dissertation is structured into three chapters. Chapter I examines the primary objective of this study. In contrast, the other chapters provide supplementary and novel information on cannibalism and document the first occurrence of a taxon in the region. Chapter I addresses cryptic diversity in Callinectes swimming crab species on the Brazilian Amazon coast using phylogenetic analyses based on four mitochondrial markers (Cytochrome c oxidase subunit I: COI; 12S rRNA: 12S; 16S rRNA: 16S; and Cytochrome b: Cyt b) and one nuclear marker (ATP/ADP translocase). Different species delimitation methods (ABGD, ASAP, PTP, and GMYC) and haplotype networks were also used for population analyses. A total of 117 specimens were captured and identified, of which 50 were included in the analyses: 25 identified as Callinectes bocourti Milne-Edwards, 13 as Callinectes danae Smith, 1869, six as Callinectes exasperatus Gerstaecker, 1856, three as Callinectes ornatus Ordway, 1863, and three identified as Callinectes marginatus A. Milne-Edwards, 1861. A total of 43 sequences were produced for mitochondrial DNA and four for nuclear DNA, some of which are novel for Brazil and the Brazilian Amazonian coast. Most of the markers analyzed were able to recover monophyletic groups for each species, except for C. marginatus and Callinectes larvatus Ordway, 1863, which clustered into a single clade, suggesting a recent speciation process. The delimitation models were able to recover MOTUs, which in most cases corresponded to the species and the identification assigned to the sequences extracted from the databases. The results revealed that species from the east coast of the Amazon exhibit unique and contrasting genetic patterns. At the population level, the only species that showed divergence were C. bocourti and C. ornatus, suggesting the possible existence of cryptic diversity in these species. Chapter II presents the first record of C. marginatus in the state of Maranhão, with three individuals collected in the eastern region of the Brazilian Amazon coast, expanding the distribution map of this species along the Brazilian coast. Chapter III describes, for the first time, a case of cannibalism between two individuals of C. ornatus under natural conditions, providing new information on the behavior of this species and suggesting a possible mechanism of population regulation. Our study not only fills a historical gap in the knowledge of Callinectes on the Amazonian coast, being the first phylogenetic work carried out in the region,but also presents the first record of C. marginatus occurrence in Maranhão and the unprecedented description of natural cannibalism in C. ornatus. This information is of extreme relevance, as it expands the knowledge about the aquatic biodiversity of the Brazilian Amazonian coast and serves as a basis for effective management and conservation measures for this important fishery resource.

Abordagem filogeográfica de gastrópodes límnicos do gênero Biomphalaria no Brasil

2026-01-01T00:00:00Z

Título: Abordagem filogeográfica de gastrópodes límnicos do gênero Biomphalaria no Brasil Abstact: Freshwater gastropods are fundamental components of continental aquatic ecosystems, performing relevant ecological functions and presenting significant sanitary importance, especially due to the role of some species as intermediate hosts of parasites of medical interest. In Brazil, species of the genus Biomphalaria stand out for their wide geographic distribution and for their direct relationship with the transmission of schistosomiasis, making them a priority target for ecological, evolutionary, and epidemiological studies. Despite this, gaps still remain regarding the genetic diversity and phylogeographic patterns of these populations. In this context, this dissertation aimed to investigate the phylogeographic patterns of freshwater gastropods of the genus Biomphalaria in Brazil, with emphasis on genetic diversity, population structure, and the influence of different biomes on the genetic organization of these species. For this purpose, sequences of the mitochondrial COI gene obtained from the GenBank database and from the DNA and Tissue Collection of the Maranhão Fauna (CoFauMA) were used, integrating analyses of genetic diversity, genetic distances, haplotype networks, and phylogenetic reconstructions using the Maximum Likelihood method. The results revealed high levels of genetic diversity in Biomphalaria glabrata and Biomphalaria straminea, with contrasting patterns of population structuring. B. glabrata showed greater genetic differentiation associated with geographic distribution, whereas B. straminea demonstrated greater population connectivity and wide haplotypic dispersion. Phylogenetic analyses confirmed the monophyly of the species and revealed genetically structured groupings according to the Brazilian biomes. Overall, the results highlight patterns of genetic diversity and population structuring in the analyzed species, contributing to the understanding of the genetic variability of freshwater gastropods in Brazil. Furthermore, they reinforce the importance of using molecular tools to investigate the diversity and genetic distribution of these organisms, providing relevant information for ecological and epidemiological studies associated with these mollusks

Caracterização e refrigeração do sêmen de Cynoscion acoupa (Lacepède, 1801), (Perciformes: Sciaenidae): informações básicas para reprodução e conservação da espécie

2026-05-29T00:00:00Z

Título: Caracterização e refrigeração do sêmen de Cynoscion acoupa (Lacepède, 1801), (Perciformes: Sciaenidae): informações básicas para reprodução e conservação da espécie Abstact: Fish represent the most diverse group of vertebrates on the planet, encompassing approximately 37,553 described species. Within marine biodiversity, the acoupa weakfish (Cynoscion acoupa) stands out as a strategic resource of significant commercial and ecological value, particularly in the North and Northeast regions of Brazil. Despite its importance, intense anthropogenic pressure has caused a sharp decline in its natural stocks, raising its status on the IUCN Red List to Vulnerable (VU). Faced with the threat of a fishery collapse, the development of reproductive biotechnologies emerges as a crucial tool for conservation and cultivation. The objective of this study was to characterize and refrigerate the semen of C. acoupa, determining the post-capture viability window of gametes under refrigeration and evaluating the physicochemical and morphological parameters of fresh semen. The study was conducted at LARAQUA/UEMA, with 18 male specimens captured in the RESEX of Cururupu - MA, using gillnets (200 mm mesh), under an ICMBio/SISBio license and CEUA approval. The animals were euthanized by hypothermia, subjected to biometry, and the gonads were extracted. For the viability test (n=8), the gonads were kept under refrigeration (4 to 6 °C) and the semen was evaluated at 0, 30, 60, 90, 120, and 150 minutes. For characterization (n=10), color, pH, motility rate and duration, sperm concentration, and morphology (Rose Bengal staining, 200 cells/slide) were evaluated. Data were analyzed via ANOVA and Tukey's test (𝑝 < 0.05). The results showed: specimens with a mean weight of 11.4 ± 1.6 kg and a mean length of 87.8 ± 4.7 cm, characterizing them as mature adults. In the viability assay, fresh semen (time 0 min) exhibited motility rates above 90% and movement duration exceeding 5 minutes. No statistically significant differences were detected in the motility rate between 0, 30, and 60 minutes, and at 90 minutes the semen still exhibited a robust rate of 76.3%, demonstrating practical viability for onboard processing. Characterization revealed white semen with a milky appearance, a pH of 6.8, and a mean sperm concentration of 1.75 X 108 cel.mL-1. Morphological analysis demonstrated a high index of normal spermatozoa (74.3 ± 13.5%), with predominantly primary abnormalities (short and coiled tail) and low rates of secondary alterations (8.8 ± 3.7%). It is concluded that the male gonads of the acoupa weakfish present a critical viability window of up to 90 minutes under post-capture refrigeration, and that the observed physicochemical parameters and high morphological integrity consolidate fundamental data for the refinement of artificial insemination and cryopreservation protocols for the species.