INDUCED SPAWNING OF DOURADO (<em>Salminus maxillosus</em> Valenciennes, 1849), AT THE RESEARCH AND ENVIRONMENT DEVELOPMENT STATION OF VOLTA GRANDE – Cemig/EPDA-VG

Abstract

A sample of eleven (11) reproductive specimens of dourado (5 females and 6 males), with a total weight of 18.6kg (9.9kg of females) was investigated at EPDA-VG, MG, Brasil. At the selection the females showed a quite large abdomen with a reddish genital papilla and the males expelled sperm abundantly showing small prickles on the anal fin. A total of 134mg of commom-carp pituitary, using three (3) doses for both males and females (0.25 – 0.5 – 5.0mg of dry pituitary/kg of live weight) were injected in the muscle under the dorsal fin using 0,1ml of physiologic serum/kg of live weight as a solvent, being the intervals between the 3 doses 24 and 12 hours, respectively. With the degree-hour ranging from 123 to 153 after the last dose, a 100% spawning efficiency was obtained, when 1,123g of eggs were incubated at a mean fertilization rate of 73%, nine hours after the fertilization, resulting in 418,928 larvae. Two days after the absorption of the yolk sack, the post-larvae of Dourado were transferred to outdoors tanks and subjected to a semiintensive culture. At the end of the 17-day experience, 4,385 Dourados with an average weight of 2.17g and a total length of 6.08cm were obtained.