Aspectos da biologia reprodutiva do niquim Lophiosilurus alexandri Steindachner, 1876 (Actinopterygii, Pimelodidae) e crescimento da progênie em diferentes condições ambientais.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

This work was accomplished at Estação de Piscicultura de Paulo Afonso, belonging to the Hidro-Electric Company of San Francisco (CHESF) (09o 2238 S and 38o1358 W), Paulo Afonso, BA, in the period from fevereiro/2001 to fevereiro/2002. It had the objective to study the aspects of reproductive biology of the niquim Lophiosilurus alexandri Steindachner, 1876 and to evaluate the growth performance of its offspring, during the early life phases under different environmental conditions. This work offers subsidies for the propagation of the species in the natural environment, i.e dams and rivers and for the commercial pond-net culture in the reservoirs of CHESF. The growth of the niquim was investigated during the early life phases under different conditions of lightness (100, 50 and 0% of light). In each condition two alimentary approaches were used: plankton + balanced food and branconeta (Dendrocephalus brasiliensis) + food (in the ration of 1:1, in volume), each one with two replications. In the first experimental trials twelve incubators were used (capacity of 80 liters), for the photoperiod treatments associated to the diet type. Each incubator receaved 200 offsprings. Soon after, the growth was evaluated in pond-nets, with those fingerlings that presented better growth in the in the previous experimental conditions. One treatment was done with three repetitions. Here, it were used three pond-nets of 1m3, in which each were placed l30 juveniles, for 248 days of cultivation. In order to verify the statistical difference among the growth of the niquins in the different conditions of brightness and food, it was used the Analysis of Variance (ANOVA), with the significance level of 5%. Informations on the aspects of the reproductive biology of the niquim were obtained from bibliographical references and from the experimental results caried out along the present work. The results indicate that the mainly period of reproductive activity of the niquim happens between September to March (83,24% of the spawnings total number). In SL treatment (without light) it was observed the best length performance, with averages of 71.25 + 8.10 mm and 74.70+5.95 mm, for the alimentary approaches plankton+food and (food+branconeta), respectively. In the present work, niquim reached the average weight of 101.77+ 20.70 g, in248 culture days. According to the results, it was concluded that the brightness influences the growth of the niquim during the embryological early phases, and with 10 cm of length , (around 20 grams), it can be realeased safely in large reservoirs and starting hight densities cultivation in pond-net, with meshes up to 12 mm.

ASSUNTO(S)

juvenile lophiosilurus alexandri recursos pesqueiros e engenharia de pesca bagre aquicultura brightness niquim pond-net luminosidade tanques-rede catfish, native

ACESSO AO ARTIGO

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