Influência do Biofilme na Sobrevivência e no Crescimento de juvenis do Camarão-Rosa Farfantepenaeus paulensis Cultivados em Sistema de Berçário no Estuário da Lagoa dos Patos.
A series of trials evaluated the attachment of biofilm to different substrates and the influence of biofilm in the survival and growth of the pink-shrimp Farfantepenaeus paulensis reared in nursery cages in a shallow estuarine inlet of Patos Lagoon, southern Brazil. The first trial tested the capacity of six types of net material to fix biofilm: white and green polyethylene nets (1mm mesh size), sack cloth from commercial shrimp diets, polyamide nets (12mm mesh size), and PVC-coated polyester nets (1.5 and 5mm mesh size). These materials were immersed in water in situ during 28 days and were sampled weekly to estimate the chlorophyll a content. The final chlorophyll a content values ranged from 3.68 to 9.34 mg/cm2, with the polyethylene nets producing the best results. The second trial evaluated the survival and growth of shrimp reared in cages during 30 days. Three 4m2cages were installed in the estuary 15 days before the beginning of the trial and the biofilm attached to them was not cleaned off throughout the experimental period. Three other cages were exchanged every 10 days in an attempt to limit biofilm attachment. At the end of the trial, there was no significant difference in survival, but postlarvae from the treatment with biofilm had a significantly (p<0,05) higher growth than those reared in cages where biofilm attachment was reduced. The third trial assessed the effects of increasing the surface available for biofilm fixation in the survival and growth of shrimps. Cages were placed inthe water 15 days before stocking. Two treatments were applied: in the first one 8m2 of polyethylene nets were placed inside the cages, while in the other no extra substrates wereadded. At the end of the trial postlarvae from the treatment with added substrates had a significantly (p<0,05) higher survival and growth than those reared in cages with no extrasubstrate. In the first and the third trial the microbial composition of the biofilm was evaluated The results of these trials showed the importance of the biofilm and the use ofextra substrates in F. paulensis nursery systems.
Advisor:Ronaldo Olivera Cavalli; Wilson Francisco Britto Wasielesky Junior; Paulo Cesar Oliveira Vergne de Abreu; Luis Alejandro Vinatea Arana
School:Fundação Universidade Federal do Rio Grande
Source Type:Master's Thesis
Keywords:biofilme Farfantepenaeus paulensis biofilm shrimp nursery microorganisms
Date of Publication:06/02/2003