The objective of this work was to evaluate a recirculating aquaculture system using biological aerated filters in tanks for tambaqui (Colossoma macropomum) fingerlings farming, with two initial stocking densities (1.4 and 2.5 kg m -³). The biofilters had similar materials (media) and the same granulometric standards, but inverted orders of the media (classic and inverted). The following were monitored for 90 days: water quality; zootechnical, parasitological, and hematological parameters; and hematimetric indices. Water temperature, oxygen levels, pH, electrical conductivity, and dissolved solids concentration were compatible with tambaqui farming and did not differ between the different biofilters and densities. The ammonia and nitrite value was associated with the stocking densities and not with biofilter. The zootechnical and hematological parameters and the hematimetric indices evaluated were not influenced either by the type of biofilter or by the stocking densities. Ichthyophthirius multifiliis, Anacanthorus spathulatus, Notozothecium janauachensis, and Mymarothecium boegeri were the parasites found. The aerated, classical, and inverted biological filters have similar efficiency in maintaining water quality parameters for tambaqui fingerling farming.

Aquaponics is a science that integrates animal aquatic production with vegetable culture in recirculating water systems. The performance of an aquaponics system using constructed semi-dry wetland with lettuce (Lactuca sativa L.) planted on treating wastewater of culture of shrimp Macrobrachium amazonicum was evaluated. Each aquaponics module consisted in four culture tanks (1 m 3 tank −1), conical sedimentation tank (0.1 m 3), circular holding tank (0.2 m 3), and constructed semi-dry wetland (0.2 m × 1.0 m × 4.0 m). Post larvae (PL) shrimps with an initial average mass of 314 ± 4.75 mg were stocked at density treatments in quadruplicate: (A) 40 shrimps m −2 , (B) 80 shrimps m −2 , and (C) 120 shrimps m −2. Our results showed the average final mass of shrimps had a slight reduction at the density 80 and 120 shrimps. However, it did not differ significantly between the treatments. The ultimate survival and productivity were higher in density 80 and 120 shrimps. The maximum biomass productivity occurred at the treatment with density 120 shrimps. The aquaponics recirculation system using constructed semi-dry wetlands with lettuce adequately treated the water at the densities tested. Various water quality parameters were deemed suitable for shrimp culture, but for lettuce not, especially the temperature. The shrimp density was inappropriate which limited the system to accumulate and increase the concentration of nutrients to vegetables with lessening the yield. Nonetheless, the system with higher density has higher nutrient content that plants demonstrated significantly better growth and yield. The results showed the potential use of organics waste generated in a family lettuce hydroponic production, but for a commercial production is indicated supplementation with nutrients like calcium, magnesium, and potassium in the water.

This study aimed to determine artificial semi-dry wetlands' performance to wastewater treatment from fish farming and Lactuca sativa production in an aquaponics system. This trial model observed the effects of different stocking biomass on the growth rate of Colossoma macropomum and yield of two L. sativa varieties. A factorial design consisting of three fish density treatments in quadruplicate and two Lettuces variety was used. Nine hundred and sixty fingerlings with 8.35 ± 0.91 g were stocked at three stocking biomass treatments in quadruplicate: 40 fingerlings or 334 g m −3 ; 80 fingerlings 668 g m −3 ; 120 fingerlings or 1002 g m −3 . Delice American Lettuce and Purple Crested Lettuce were cultured in the semi-dry wetlands. The final mass (g), consumed food, feed conversion ratio, and yield of fingerling were statistically different between the tested densities, but survival did not. The artificial semi-dry wetlands were efficient on water treatment and the recovery of nutrients in all fish densities trials, and it has potential as support for lettuce production. The recovery of nutrients was shown on the increment of the number of leaves, total fresh mass (g), and lettuces yield by area (kg m −2 ) in both varieties of plants tested. Precocious flowering in 30% of lettuce varieties, incidence of mealybug and whitefly, temperature and deficiency of calcium and magnesium were factors that may have compromised the full lettuce development. The aquaponics system efficiently treated the fish effluent at the densities tested, being appropriate for fish farming and lettuces production.

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O camarão-da-Amazônia Macrobrachium amazonicum (Heller, 1862) é uma espécie nativa amplamente distribuída na América do Sul. As relações biométricas possuem como finalidade estimar diferenças entre os sexos ou populações. Este estudo tem o objetivo de verificar a estrutura populacional com ênfase na razão sexual, relação peso-comprimento e fator de condição do camarão-da-Amazônia na foz do rio Amazonas. As coletas foram realizadas com armadilhas denominadas de matapi com espaçamento entre talas de (1, 2, 3, 4, 5, 6, 7, 8, 9, 10mm). Cada armadilha foi coberta com uma rede, denominada de sobrematapi. Foram registrados o comprimento da carapaça em centímetros e o peso individual em gramas de cada indivíduo. Do total de 19.967 camarões coletados 14.116 foram fêmeas, 5.806 machos e 45 de sexo indeterminado. As fêmeas variaram de 0,5 a 2,7 cm de comprimento da carapaça com média de 1,24 ± 0,47 cm e peso variando de 0,10 a 13,49 g com média de 2,09 ± 2,41 g. Para os machos a variação de comprimento foi de 0,5 a 3,3 cm com média de 1,50 ± 0,46cm, enquanto a variação de peso foi de 0,21 a 18,83 g com média de 3,19 ± 2,71 g. A variação de comprimento para os camarões de sexo indeterminado foi de 0,2 a 0,8cm com média de 0,68 ± 0,09 cm. O peso variou de 0,01 a 1,17 g com média de 0,26 ± 0,11 g. Os comprimentos da carapaça foram diferentes entre os meses e sexos. Os machos foram maiores que as fêmeas. A proporção entre os sexos foi muito diferente, sendo 2,43:1 (2,43 fêmeas para 1 macho). A proporção sexual foi diferente entre os meses, sendo as fêmeas mais abundantes. Os valores de b para machos e fêmeas diferem de 3, portanto os valores para ambos os sexos são menores que 3, indicando crescimento alométrico negativo em todos os meses. O fator de condição para machos e fêmeas diferiu de 1, quando comparados no geral entre os sexos, houve significância. Em todos os meses não houve diferença entre os sexos, exceto no mês de maio. O estudo da estrutura de população, com ênfase na relação peso-comprimento, proporção sexual e fator de condição, é uma importante ferramenta para entender a biologia de M. amazonicum.