Effect of water flow rate and feed training on "pacamã" (Siluriforme: Pseudopimelodidae) juvenile production

R.K Luz,M.M Pedreira,E.A Teixeira,J.C.E Santos

doi:10.1590/s0102-09352011000400024

Abstract

The effects of different water flow rates and feed training on the production of "pacamã" Lophiosilurus alexandri juveniles were evaluated. In the first experiment, nine day post-hatch larvae (n= 2,400) were stocked at a density of 5 larvae/L. Different water flow (F) rates were tested: F1 = 180; F2 = 600; F3 = 1,300; and F4 = 2,600mL/min. Artemia nauplii were offered as food during the first 15 days of active feeding. In the second experiment for feed training, 720 juveniles (total length of 22.2mm) were stocked at a density of 1.5 juveniles/L. A water flow rate similar to F1 was used. The use of extruded dry diet was tested, and feed training was done with and without other enhanced flavors (Artemia nauplii or Scott emulsion). The water flow rates did not influence the survival or growth of L. alexandri. Cannibalism occurred during feed training. The worst survival, specific growth rate and high mortality were found with the use of extruded dry diet, while similar values were registered with the different feed training diets used. Reduced water flow rate can be used to lower water consumption during larviculture and feed training of L. alexandri.

Highlights

The “pacamã” Lophiosilurus alexandri is a carnivorous freshwater fish, native to the São Francisco River, MG (Shibata, 2003) with the potential for farm production
In the Integrated Center of Fisheries and Aquaculture Resources (ICFAR) of Três MariasCODEVASF, MG, the L. alexandri larviculture has been carried out with continuous water flow leading to high water consumption and waste
During the feed training, the darkness regimen kept the juveniles scattered in the canals, while in the natural photoperiod conditions of the initial phase, the larvae grouped together in the corners of the canals

Summary

Introduction

The “pacamã” Lophiosilurus alexandri is a carnivorous freshwater fish, native to the São Francisco River, MG (Shibata, 2003) with the potential for farm production. Its meat is of excellent quality, taste and has few bones. This species is important for fisheries and in the reservoir restocking program, in which juveniles with a total length of over 1.5cm are used. The lack of research on the weaning strategies is one of the bottlenecks for the successful juvenile production of this species. In the Integrated Center of Fisheries and Aquaculture Resources (ICFAR) of Três MariasCODEVASF, MG, the L. alexandri larviculture has been carried out with continuous water flow leading to high water consumption and waste. Davison (1997) related that for several salmonidae, the speed of water can increase the growth of animals and moderate their aggressive behavior. Judicious use of water is necessary due to its importance to humans, animals and agriculture

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