Effects of three planting densities and food availability on the development and survival of larval yaque, Leiarius marmoratus (Pisces: Pimelodidae)

Abstract

This research was developed in the laboratory of live food production of the Institute of Aquaculture (IALL), University of the Llanos (UNILLANOS), located at Km 4 way to Puerto Lopez, Barcelona sidewalk city of Villavicencio (Meta) to 418 m.a.s.l. Considered objectives are to evaluate the productive performance of yaque (Leiarius marmoratus) larvae under three planting densities (15, 30 and 45 larvae/liter) and three regimes of live food supply (250, 500 and 750 nauplii/larva), in controlled laboratory conditions, and measure the increase in weight and size, the specific growth rate, relative growth factor and survival rate of yaque during the larval stage under three conditions of plant densities and three feeding regimens. For the study were obtained yaque larvae through artificial reproduction using protocols developed at the Instituto de Acuicultura de los Llanos. Larvae under study were taken at 48 hours post-hatching, with 90% of yolk sac resorption. 54 tanks were used 4 liters of capacity, which were maintained with a volume of 3 liters of water, constant aeration and daily turnover of 50%. The average temperature was maintained at 27°C. Use two-factor design was completely random. The factors evaluated were plant densities and concentration of food supply. The data were processed using descriptive statistics as mean and standard deviation. To check the effect of the specific density and food concentration, was made an analysis of variance (ANOVA) under the GLM procedures of SAS, reviewing the assumptions of normality (Kolmogorov-Simirnov) and homogeneity of variances (Levena test) also was used as the test of Tukey post-test to compare means between different treatments. The significance criterion was managed at a level of p<0.05. Parameters such as temperature, conductivity, total solids and dissolved oxygen, measured throughout the test did not differ significantly between treatments hydrogenionic potential values ​​(pH) of water showed significant differences, since decreased as concentration increased Artemia salina provided. Stocking densities maintained by the higher survival rates were 30 and 45 larvas.L-1, with the availability of 250 nauplii of Artemia salina provided. The results obtained in this experiment show that this species has marked an era of cannibalism between day 0 and day 8. The requirement for live food is a major limitation in this species. The densities handled directly responded to the type and amount of feed used with the result that the highest densities with adequate food availability is a greater survival although their weight and height gain is relatively slow. For the commercial chain of Silurids of the region, these results favor the improvement of technological management of this species.