Producción intensiva de ovas embrionadas de pejerrey (<i>Odontesthes bonariensis</i>) a partir de reproductores mantenidos en cautiverio

Abstract

The aim of this work was the obtainment of Odontesthes bonariensis eggs from broodstocks reared in captivity since them hatched. The experiment took place from September 2005 to April 2006 during this time fish were kept in two circular tanks of 20 m2 (A1 and A2), with water salinity of 9 g/l and 3,6 times/day water volume changes. Water temperature varied from 17 to 22,5ºC. Broodstocks were fed with artificial food twice a day at 1% of body weight/day. The initial densities were 20,4 (A1) and 18,7 (A2) ind/m2. The male/female relationship was 1,02 (A1) and 0,86 (A2). Mean standard length of A1 reproducer was 293,1mm and 286,3mm in A2. Mean weight was 322 g (A1) and 306,4 g (A2). From A1 7.868.550 eggs with a 74,31 % fertilization rate and 6.061.790 with 75,11 % fertilization rate in A2 were obtained. During the first fifteenth of October the greater percentage of eggs was collected 25.01 % in A1 and 29.14 in A2. Each A1 female spawned 39.942 eggs in average and 32.208 in A2. Reproducers survival rates were 96,98 % and 94,66 % (A1 and A2). Finally we think that massive egg production with a high fertilization rate is possible from high densities of reproducers reared in captivity.