Objetivou-se, neste trabalho desenvolver uma metodologia para produção de biomassa de "branchoneta" Dendrocephalus brasiliensis Pesta, 1921. Os experimentos foram realizados na Estação de Piscicultura da CHESF, Paulo Afonso-BA, com a finalidade de viabilizar a branchoneta como fonte alternativa de alimento na aqüicultura. A metodologia constou de dois tratamentos (com e sem inoculação de cistos de D. brasiliensis) realizada em duas épocas distintas (maio e outubro), com duas repetições. Foram utilizados quatro viveiros semi-escavados. Após a ANOVA (P<0,05) constatou-se que o tratamento com inoculação apresentou uma produção média de 18,63 ± 0,74 kg superior a 8,00 ± 0,75 kg do outro tratamento, podendo-se assim produzir uma biomassa de 1.863 kg/ha/ano. Os resultados obtidos recomendam produção de biomassa de D. brasiliensis utilizando a metodologia de inoculação de cistos.

This work aimed to develop a methodology for the production of biomass of "branchoneta" Dendrocephalus brasiliensis Pesta, 1921. The experiments were accomplished at Paulo Afonso Fishculture Station of CHESF, BA, with the purpose of making possible the branchoneta as an alternative source of food in the aquaculture. The methodology consisted of two treatments (with and without inoculation of D. brasiliensis cysts) carried out at two different times (May and October), with two repetitions to each treatment. Four semi-excavated ponds, each with an area of 2000 m², were used. After ANOVA (P < 0,05) it was verified that treatment with inoculation showed the best results: 18,63 ± 0,74 kg superior to 8,00 ± 0,75 kg of the other treatment. This suggests an average biomass production of 1.863 kg/ha/year. The results obtained recommend production of biomass of D. brasiliensis using the methodology of inoculation of cysts.

Neste estudo foram capturados 209 exemplares de Astyanax fasciatus (Cuvier, 1819), sendo 100 fêmeas e 109 machos, no Rio Ceará Mirim, Rio Grande do Norte (5°37'S e 35°39'W), durante o período de fevereiro 1996 a abril de 1997. A proporção entre os sexos, não difere significativamente de 1:1, com uma leve predominância de machos. A distribuição de freqüência percentual de machos e fêmeas por classes de comprimento total, evidencia que a amplitude de variação de comprimento está compreendida entre 3 a 9 cm, com predominância nas classes 4-5 e 7-8 cm. O valor estimado do coeficiente angular (q = 2,59), sugere que a espécie apresenta um crescimento do tipo alométrico negativo. O IGS tende a aumentar a partir do trimestre novembro-dezembro-janeiro, alcançando seus maiores valores no trimestre seguinte, coincidindo com a elevação das médias dos valores de precipitação pluviométrica, enquanto que, o fator de condição tende a apresentar os valores médios inferiores neste período.

The aim of this study was to evaluate 209 samples (100 females and 109 males) of Astyanax fasciatus (Cuvier, 1819) collected from the Ceará Mirim River, Rio Grande do Norte State, (5°37'S e 35°39'W), between February 1996 and April 1997. The sex ratio was 1:1 and the the total length varied from 3.0 to 9.0cm, with most classes between 4.0-5.0 cm and 7.0-8.0 cm. The estimated value for the parameter (q = 2,59) suggests that this specie has an alometric growing pattern. The IGS value started to increase in November-December-January, following the rainfall while the condition factor values showed.

The goal of this study is measure the food ingestion by M. roosevelti Eigenmann, 1915 emphasizing its feeding rhythmic. The observations were made between March 1994 to February 1995, in Jiqui Lake, Rio Grande do Norte State. The sample involved 1115 individuais, including 503 males and 613 females, collected in five waiting-net with length of 5.0 to 5.0 m and mesh of 2.0, 2.5 and 3.0 cm between opposites joins, that were exposed for 24 hours and reviewed each 6 hours. The food ingestion was predominant between 6:00 AM to 12:00 AM for males and between 6:00 PM to 12:00 PM for females. The condition factor showed lower values between 6:00 PM to 12:00 PM for males and between 12:00 PM to 6:00 AM for females. The mean level of repletion showed higher values between 12:00PM to 6:00PM for males and between 6:00 PM to 12:00 PM for the females. The higher levels of repletion index for males were observed between 12:00 AM and 12:00 PM for the females and between 6:00 PM to 12:00 PM for males. For this species, plankton constituents, specially algae, are its preferential food.

This species showed feeding activily ali year long. Although zooplancton, protozooplancton and other organisms have been found in the stomaches, this species can be considered, broadly speaking, herbivorous since a great amount of seaweed was found in its diet. Fulness of the stomachs was not associated with sex difference. Full stomachs were found throughout the period. Variations according to the estimated periods were not found.

The time of full stomach repletion and fat condition was determined through an analysis of the average stomach repletion index, condition faclor and relative frequency of repletion for different periods of the year. Condition factor was influenced by weight gain in the stomaches, main from April to June.