Na busca pelo conhecimento sobre sanidade de peixes a compreensão das interações ecológicas é fundamental, mas por um longo tempo houve negligência nos estudos sobre os parasitas que os afetam. Os trabalhos com patógenos de peixes no Estado do Maranhão ainda são insuficientes e por essa razão este trabalho vem com o objetivo de realizar um levantamento de pesquisas científicas desenvolvidas no período de 2010 a 2020 sobre os de patógenos em peixes de ambientes naturais e de cultivo deste estado. Utilizou-se como estratégias metodológicas a busca sistemática por artigos científicos nas plataformas Web of Science, Google Acadêmico, Pubmed, ASFA, Scopus e SciELO, no período compreendido entre 2010 a 2020, com o intuito de reunir informações sobre o tópico em estudo. Os resultados foram separados por categoria de agentes etiológicos pela diversidade de classes e técnicas distintas utilizadas nas pesquisas levantadas. Os dados obtidos evidenciam que os peixes podem ser acometidos por crustáceos ectoparasitas, bacterioses, nemátodas, protozoários, mixosporídeos, fungos, monogenóideas e vírus, porém no Maranhão as pesquisas com esses parasitas de peixes ainda são incipientes, neste sentido destaca-se a necessidade de mais estudos sobre sanidade de peixes nesta região.  Além disso, estudos detalhados sobre o ciclo de vida dos parasitas e suas vias de transmissão com finalidade de prevenir as infecções, bem como a construção de um plano de ação com estratégias de tratamento, controle e prevenção dessas patologias serão de grande relevância em estudos futuros e ambientalmente sustentáveis.

Estudo dos aspectos reprodutivos do trichiurus lepturus (linnaeus, 1758) na Costa Maranhense, Brasil Study of the reproductive aspects of trichiurus lepturus (linnaeus, 1758) in Costa Maranhense, Brazil

Zooplankton is a group of organisms that can help to understand the quality of aquatic ecosystems, as they are responsible for transforming energy matter, thus making it available to other links, making them important in aquatic trophodynamics. This study analyzed spatial and temporal variations in zooplankton communities found in two tidal control structures on Ilha do Maranhão, northeastern Brazil. Sampling took place from September 2017 to July 2018. Abiotic parameters (temperature, salinity, and transparency) and plankton samples were recorded monthly throughout the study period at each sampling site. The results found for the abiotic parameters showed a well-defined pattern, with a clear division between the dry and rainy periods. Forty taxa represented the zooplankton community of the São Luís tidal control structure, and from São José de Ribamar by 21 taxa, represented mainly by copepods, ichthyoplankton, foraminifera, polychaetes, and mollusks. The analysis of ecological indices of richness, evenness, and diversity showed a difference in the distribution of organisms among the study areas. We identified an important influence of the physicochemical parameters on the zooplankton communities of São Luís and São José de Ribamar, according to the statistical analyzes used in this study.

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The current study aimed to investigate the ectoparasitic diversity and gill alterations in Hoplerythrinus unitaeniatus (Characiformes: Erythrinidae) and Cichlasoma bimaculatum (Perciformes: Cichlidae) and evaluate the microbiological and physicochemical quality of water samples deriving from a Quilombola zone in Maranhão State, Brazil. Water samples and 42 fish specimens, 21 H. unitaeniatus and 21 C. bimaculatum, were collected from a floodable environment. Water samples were subjected to physicochemical and microbiological analyses in the laboratory environment. Fish specimens were euthanized to collect and identify ectoparasites in animals' mucus, body surface, and gills, as well as to enable the histological analysis of the second right gill arch. The herein-identified ectoparasites have shown 30.95% prevalence and comprised three phyla: Platyhelminthes, Trematoda and Arthropoda. The herein-identified main histological changes comprised incomplete and complete fusion of several lamellae, lifting of respiratory epithelium, lamellar disorganization, lamellar epithelial hyperplasia, and blood sinus dilation. The herein calculated histological alteration index has shown that 23.80% of specimens presented mild-to-moderate tissue damage, 4.77% presented moderate-to-severe tissue changes, and 9.52% presented irreparable tissue damage. It was possible concluding that histological gill lesions identified in fish specimens analyzed may be adaptive responses to the affected environment and the incidence of ectoparasites.

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