This work describes the detailed ultrastructural morphology of the phagocyte imprisoning an oyster of Nematopsis (Apicomplexa) found in Crassostrea rhizophorae, in the city of Maceió (AL), Brazil. The highly infected hosts had half-open leaflets with weak, slow retraction of the adductor muscles. Variable number of ellipsoid oocytes, either isolated and or clustered, was found between myofibrils of the adductor muscle. Each oocyst was incarcerated in a parasitophorous vacuole of host uninucleated phagocyte. The oocysts were composed of a dense wall containing a uninucleate vermiform sporozoite. The wall of the fine oocysts was composed of homogeneous electron-lucent material formed by three layers of equal thickness, having a circular orifice-micropyle obstructed by the operculum. The oocysts presented ellipsoid morphology with their wall was surrounded by a complex network of numerous microfibrils. Important details of the taxonomic value were visualized such as the ultrastructural organization of the oocyst wall and the organization of the micropyle and operculum, beyond the microfibrils that protrude from the oocyst wall only observed by transmission electron microscopy (TEM) and that may aid in the identification of the species. However, in order to clarify the systematic position of the species reported of the genus Nematopsis, it is important to proceed with genetic analyses.

The São Francisco River represents 2/3 of the Northeast Region freshwater availability. Its basin is divided into Upper São Francisco, Middle São Francisco, Sub-Middle São Francisco, and Lower São Francisco. The Lower São Francisco is one of the most impacted regions of the Northeast, considering factors related to fishing, electric power generation and city sewage pollution. The first Scientific Expedition of the Lower São Francisco aimed at evaluating the water quality, pollution, silting, deforestation of the ciliary forest, socioeconomic survey, environmental education, ictiofaunal composition, analysis of metals in fish, fishing and catching and salt intrusion. The samples were collected in seven coastal municipalities in the states of Alagoas and Sergipe. The results indicate that all the municipalities studied have water pollution problems from household and diffuse sewages, pesticides, and organic matter deposited in the sediment. Much of the crops are dependent on the use of agrochemical in crops on the banks of the river, with a prevailing environmental degradation scenario. There was a decrease in the number of native fish species and predominance of exotic and invasive marine species. In addition, it was possible to detect the occurrence of catch methods with high impact on the fishes. The saline wedge is already 16 km from the river mouth, replacing agricultural activities by shrimp farming. Fish show metal content, but a large part of them are within acceptable limits and a georeferenced database with the results of the expedition was made available for consultation.

ABSTRACT.Eugerres brasilianus is an appreciated commercial species in the market of the northeastern region of Brazil. The purpose of this study was to analyze and determine the diet, reproductive period, and management of carapeba in recirculating aquaculture systems. The fishes were caught with a gillnet at two different places near the São Francisco River mouth. The stomach content was analyzed according to the frequency of occurrence method, using the index of relative importance, assessing the degsubjectedree of stomach repletion. The reproductive period was established by determining the gonadosomatic index and gonad maturation stages. The behavior and management of the fish were observed in captivity when subjected to artificial diets in cultivation tanks. The striped carapeba is best feed at dusk, mainly Crustacea Amphipoda, Insecta Chironomidae and Crustacea Tanaidacea. The species has parceled spawning, which occurs from February to March and from July to September. There are morphological differences between males and females, especially in the urogenital papilla, size and color. In captivity, the best fish density was between 7 and 8 fish m , showing a good rates of centesimal composition, adapting well to the supplied diet. Keywords: Gerreidae, feeding, behavior, sexual maturation, reproductive period, aquaculture. Potencial de la mojarra (Eugerres brasilianus) para su cultivoRESUMEN. Eugerres brasilianus es un pez marino comercial importante en el mercado del noreste de Brasil. El objetivo de este trabajo fue analizar y determinar la dieta, período reproductivo y manejo de la mojarra en estanques de recirculación de agua para el cultivo intensivo. Los peces fueran capturados con redes agalleras en dos sitios diferentes, cerca de la desembocadura del río São Francisco. Los contenidos estomacales fueron evaluados mediante el método de frecuencia de ocurrencia, através del índice de importancia relativa, evaluando el grado de repleción del estómago. El período reproductivo fue establecido determinando el índice gonadosomático y los estadios de maturación gonadal. Se observó el comportamiento y manejo de los peces en cautividad cuando son sometidos a dietas artificiales en estanques de cultivo. La mojarra se alimentó mejor en el crepúsculo, principalmente de Crustacea Amphipoda, Insecta Chronomidae y Crustacea Tanaidacea. La especie tiene desove parcelado, que ocurre de febrero a marzo y de julio a setiembre. Existen diferencias morfológicas entre machos y hembras, especialmente con relación a la papila urogenital, tamaño y color. En cautividad la mejor densidad de peces fue entre 7 y 8 ind m -3 , mostrando buenas tasas de composición centesimal, adaptándose bien a la dieta suministrada.

Pisciculture has been an important part of the economy in many regions of Brazil, and the tambaqui (Colossoma macropomum) stands out as one of the country’s most commercialized native freshwater fish species. Loss of genetic variability can affect characteristics such as reproduction and growth rates, as well as disease resistance and is of great concern in this field. Molecular markers such as mitochondrial DNA genes have been increasingly used to understand genetic variability in species of economic importance. This study aimed to characterize the genetic variability of tambaqui populations reared in two fish farms (Itiúba, AL and Betume, SE) of the lower São Francisco River by analyzing the control region and ATPase genes of mitochondrial DNA. Sequencing of samples from progenies and breeding individuals identified 42 haplotypes (32 unique), of which four haplotypes were shared between the two fish farms as a result of a founder effect, because individuals from Itiúba formed the stock of the Betume fish farming Station. Haplotype diversity was high in both locations. Analysis of Molecular Variance (AMOVA) revealed greater genetic variation within populations (96.76%) than between them (3.24%) and the FST value (0.03) indicated low genetic differentiation between the two populations. The observed high genetic variability can be explained by the number of breeders in the two fish farms (200 in Itiúba and 1400 in Betume) and the breeding management system, which seems to be effective in maintaining stock variability.

The aim of this study was to evaluate the effects of alimentary restriction on Betta splendens performance. For the experiment, 24 males were used, with initial average weight of 0.55 ±0.06 grams, distributed in 24 experimental aquaria with 1.5 liters of water without aeration in a completely randomized design, with four treatments and six repetitions. The treatments were: T1 – daily fed animals (control), T2 - fed for six days and one day of restriction (6A/1R), T3 - fed for five days and two days of restriction (5A/2R) and T4 - fed for four days with three days of restriction (4A/3R). The fishes were fed twice a day at 08:00am and 4:00pm. The variables studied were: final weight (FW), weight gain (WG), alimentary conversion (FC), average feed consumption (CMR), total length (CTOTAL), standard length (CPADRÃO) profile index (IPERFIL), condition factor (CF) and height. The results were submitted to variance analysis (ANOVA), and the means were compared by Tukey´s test at 5% of probability. No significant differences were observed for the following variables: water quality, survival, alimentary conversion and profile index. The best growth performance was observed when the feeding management of 6A/1R was applied.