Effects of delayed first feeding on growth of the silver catfish larvae Rhamdia voulezi (Siluriformes: Heptapteridae)

ABSTRACT

The effects of the timing of first feeding on the point-of-no-return (PNR) and growth of laboratory reared silver catfish Rhamdia voulezi larvae were studied. The experiment began immediately after the complete absorption of the yolk sac, 3 days after hatching (DAH). The food was provided for the first time on 3^rd, 4^th, 5^th, 6^th, 7^th, 8^th, and 9^th DAH. Zooplankton and newly-hatched Artemia spp. were used to feed the larvae. To evaluate the effect of food deprivation on growth, the standard length and weight of 594 larvae were assessed. Larval growth was significantly affected by the time of first exogenous feeding. The larvae fed from 3^rd to 5^th DAH showed a significantly higher development than those fed from 6^th DAH. The larvae reached the PNR on 6^th DAH. Survival and larval growth strongly depended on the timing of initial feeding. In order to avoid potential mortality by starvation and obtain good growth, the silver catfish larvae R. voulezi must establish successful initial feeding within 5 days after hatching.

Keywords:
Exogenous feeding; Initial feeding; Larval development; Point-of-no-return; Starvation