The tambaqui (Colossoma macropomum) is a fish of primary importance in South American aquaculture, principally in the Amazon region and has a particularly unique diet in the wild. Oryza spp, or Wild rice as it is commonly known, is native to the floodplains of muddy rivers in the Amazon region. The aim of this study was to analyze the physical performance and the effects of dietary levels of Oryza spp. via the hematological parameters, total food intake, conversion efficiency, growth ratio and swimming performance of this fish. Diets containing 45% Oryza spp. induced the best performance in tambaqui. Diets containing 15% and 30% did not affect these indices, thus indicating that this amount of Oryza can be used as an alternative energy source for this important species within Brazilian aquaculture.

The Negro river basin is considered the largest area of extractive of ornamental fish in Brazil. This area has fundamental importance for the populations from the Amazon. The present study aimed to describe socioeconomic profile of ornamental fishermen known as “piabeiros” in the Municipality of Barcelos, as well as the ornamental fishery, fisheries area, target species, environments, fishing techniques, equipment, capture techniques and main difficulties faced by the current activity. This study was carried out in municipality of Barcelos, through semi - structured interviews, with artisanal ornamental fishermen (N= 89). The main families of ornamental fish caught and traded were: Characidae, Lebiasinidae, Gasteropelecidae, Cichilidae, Anostomidae, Loricaridae, Potamotrygonidae and Gymnotidae. The main catchment areas were igarapés, lakes, flooded fields, beaches, river banks and igapó forest. Rapiché was the most used equipment in the fisheries both by the fishermen of the urban areas (43.81%) and rural (41.89%). Most of the fishermen are associated with the colony of fishermen of Barcelos (Z33). The data showed that the dynamics of ornamental fishing have changed in a short time and directly affected fishermen, in addition to the low age renewal with the participation of younger fishermen, threatening the transmission of ecological knowledge to future generations. As a result, the increase of the problems related to the productive chain and absence of public power to the activity, since ornamental fishing has already been treated as one of the main economic activities more important for the local communities and for the State of Amazonas.

The objective of this study was to characterize and compare the hematological variables (erythrogram, thrombogram, leukogram and plasma metabolites) of three cichlid species: Cichla monoculus, Cichla temensis and Cichla vazzoleri. A total of 45 specimens were captured in Balbina lake, Presidente Figueiredo, Amazonas, Brazil, with the aid of a rod and reel or hand line, with natural or artificial bait: 15 C. monoculus, 15 C. temensis and 15 C. vazzoleri. Their blood was removed by means of caudal puncture of the dorsal aorta, and hematological data were determined in accordance with methodology previously described in the literature. The erythrogram showed similarities between the species, while the thrombogram showed differences between C. vazzoleri and the other species studied (C. monoculus and C. temensis). The total leukocyte counts for C. temensis and C. vazzoleri were higher than those of C. monoculus. The predominant leukocyte in C. temensis and C. vazzoleri was lymphocytes, whereas it was monocytes in C. monoculus. The plasma metabolites showed differences between the three cichlid species, regarding their glucose, cholesterol, urea and potassium levels. It is concluded that these three species present hematological differentiation, thus indicating that they have differentiated blood-cell immune responses and plasma metabolite physiology.

Photoperiod is considered an environmental factor that influences reproduction and the growth processes of fish throughout the year. In the present study, we subjected dusky grouper Epinephelus marginatus to different photoperiods in order to evaluate growth and survival. Juvenile dusky grouper were randomly distributed in twelve 100 L tanks containing four fish per aquarium. The fish were exposed to continuous light, normal photoperiod or continuous darkness for 50 days. Fish were fed 3% of their total biomass, twice a day, and the diet consisted of ground commercial dry pellets (42% crude protein, 12% humidity, 9% ether extract, 15% mineral matter, 4% crude fiber, 3.5% calcium and 3% vitamin C, in accordance with the manufacturer’s instructions). There was no mortality during the experiment. After 50 days, the best performance was found for exposure to continuous light (24 h artificial light). The final weight of the fish reared under continuous light was significantly higher than that of the fish exposed to continuous darkness. The specific growth rate of the fish exposed to continuous light was significantly higher than that of the fish exposed to the natural photoperiod and to continuous darkness. Modifications to the photoperiod can be a key factor in increasing the efficacy of current production and the improvement of current aquaculture protocols.

A Etnociência surge como uma importante ferramenta integradora do conhecimento acadêmico e do conhecimento dos pescadores. O objetivo do presente estudo é realizar uma análise do perfil socioeconômico e do conhecimento tradicional sobre as arraias de água doce em relatos de pescadores no município de Barcelos, Amazonas. Foram entrevistados 54 pescadores que foram afetados por acidentes com arraias. Observou-se que 89,0% são do sexo masculino, demonstrando a manutenção das atividades de pesca que são passadas pelas famílias de crianças e jovens. A proporção de casos ocorreu com pescador com mais de 50 anos (62,2%). Há uma predominância do uso de puçá e rapiché que é um tipo de pesca ativa na qual não causa nenhum dano aos animais. Um total de 2,0% não identificou as cinco espécies presentes no rio Negro. Entre os sintomas apontados pelos pescadores após o acidente, foram citados dor, edema e, algumas vezes, necrose. É possível auxiliar os pescadores de águas doce sobre como se sucedeu os acidentes, as localidades e os mecanimos de atuação dos venenos, bem como a forma com que os pescadores utilizaram para minimizar os efeitos dos ferimentos. As informações geradas aqui podem servir de base para que os ribeirinhos ao ser acidentados por arraias de água doce tenham uma forma de mitigar ou até mesmo de eliminar a dor causada pelo veneno presente nos ferrões desses animais tão temido pelos povos ribeirinhos da Amazônia.

Context: Balistes capriscus is relevant for fishing worldwide, but there is no consistent information on the maintenance of the species in a captive environment. Aims: Develop protocols for the reproduction of the species in aquaculture systems, contributing to the maintenance of the supply in the commerce through captive breeding. Methods: A Balistes capriscus couple was selected on the basis of behavioural observations. Nutritional and environmental stimuli were invested in obtaining natural spawning. After reproduction, the larvae were regularly observed under an microscope to monitor the ontogenic development. In larviculture, feeds based on Brachionus plicatilis (10 mL-1) and Nannochloropsis oculata (150 000 cells mL-1) and pate formulated with Artemia salina, Nannochloropsis oculata, sardines and commercial feed were evaluated. Key results: The eggs had a diameter of 667.5 µm (±21.66) and formed a mass adhered to the substrate. Newly hatched larvae had a total length of 1653.63 µm (±213.97). The first food intake was evidenced 72 h after hatching; however, larvae did not survive more than 6 days. Conclusions: The reproduction in laboratory of the species is viable; however, larviculture remains a limiting factor. Implications: The success in captive breeding is essential for the introduction of B. capriscus in aquaculture, and for the conservation of the species.