Chelonians (turtles and tortoises) of the Amazon Basin have constituted a source of food for native populations since pre-Columbian times and have continued to be an important product for subsistence and cash income. Little is known about current levels of exploitation and pressure on natural stocks, despite observations of declining populations of the larger and most valued species. This study investigates how people living in the Negro River area use Amazonian chelonians, including issues of consumption, preferences, restrictions, segmentary taboos, harmfulness, medicinal use, and sale. We conducted interviews with fishing families in the city of Barcelos and in Jaú National Park, both located in the Rio Negro basin, in the state of Amazonas, Brazil. All chelonian species are used by these riverine people, especially for food. Peltocephalus dumerilianus is caught year round, whereas the capture of other species is more frequent during the dry season. Terrestrial species are collected whenever found in the forest. Herbivorous species are preferred as food; omnivorous or carnivorous species are subject to food taboos. Two species are largely used as medicines, mainly to treat swelling and hemorrhages. Fat and epidermal scutes (scales) are widely used. At least four species are exploited commercially.

Consumption of turtles by natives and settlers in the Amazon and Orinoco has been widely studied in scientific communities. Accepted cultural customs and the local dietary and monetary needs need to be taken into account in conservation programs, and when implementing federal laws related to consumption and fishing methods. This study was conducted around the Purus River, a region known for the consumption and illegal trade of turtles. The objective of this study was to quantify the illegal turtle trade in Tapauá and to understand its effect on the local economy.

The physiological responses of juvenile tambaqui (Colossoma macropomum) fed commercial feed supplemented with different concentrations of camu camu (Myrciaria dubia) were evaluated. The design was completely randomized, with treatments arranged in a factorial design with three proportions of camu camu (15%, 30% and 45%) and a control treatment (100% commercial diet), with four replicates per treatment. A total of 96 tambaqui specimens were used, with a mean initial weight of 11.69 ± 2.68 g and a mean length of 7.06 ± 0.44 cm. After 30 days, hematological parameters, metabolic variables, growth and fish swimming performance were evaluated. The different proportions of camu camu in the diet did not cause significant changes to the tambaqui's hematological parameters during the feeding period, except for hemoglobin (Hb) concentration and mean corpuscular hemoglobin concentration (MCHC) after the 30th day, and hematocrit (Ht) after the swimming stress test, which increased significantly (p < 0.05). The significant increases in metabolic variables, such as cortisol, glucose, proteins and triglycerides, and in hematologic variables after the Ucrit test reflect, respectively, biochemical adaptations for maintenance of the energy mobilization process and a regulatory necessity in tissue oxygen demand during intense exercise. Fish fed 15% and 30% camu camu gained the most weight and achieved the best swimming performance, respectively. The results for camu camu concentrations above 30% suggest a saturation of its intrinsic properties in the diet at this level and a loss of nutrients from the commercial feed replaced by the fruit, reducing productive performance and nutritional assimilation.

The objective of this study is to identify the economic–financial viability, attractiveness potential, and investment risks of tambaqui farming in the state of Amazonas, Brazil. Tambaqui is the main native fish in Brazilian aquaculture. A survey was conducted for 240 fish farms, and analyzed through Monte Carlo simulations. It was found that fluctuation in feed (US$0.49 ± 0.09 kg⁻¹) and fish prices (US$1.77 ± 0.48 kg⁻¹) exerts a great influence on the profitability of the projects. In general, the results indicate that it is difficult to make the farms profitable. The use of modern technologies, such as aerators, and monosex populations on fish farms may be some alternatives to overcome this situation and improve the productivity of the sector, consequently promoting its sustainability.

Tambaqui,Colossoma macropomum is a fish of primary importance in Brazilian aquaculture and in the Amazon region in particular. The aim of this work is to analyze the combined effects of physical training and levels of dietary cassava (Manihot esculenta) on the hematological parameters, food intake, conversion efficiency, growth ratio and swimming performance of this fish. A diet for tambaqui consisting of 30% cassava caused decreases in weight gain and specific growth rate compared with the control group. Diets containing 15% or 45% cassava did not affect these indices and did not cause hematological changes in tambaqui juveniles, indicating that some amount of cassava can be used as an alternative energy source for this important aquaculture species.