Estimates of heritability for alometric condition factor from 90 to 330 days in curimbatá

Abstract

1 PROBLEMA

The relation between body weight and body length can be used to calculate the condition factor in fish. This factor express the grade of development of the fish. A sample of 253 fish from a hierarchial mating (5 females and 10 males) were used. Fishes were kept in net cages until, 150 days of age, and then marked and transferred to three tanks of I00m²/each; where they stayed until 330 days of age. The fishes were fed with a 30% crude protein and 2800 kcal/kg of metabolizable energy ration. Heritabilities of the alometric condition factor, from ages 90 to 300 days, were estimated using a model including female and mate within female. Heritabilities calculated from sire components of variance were: 0,28 ± 0,20; 0,11 ± 0,16; 0,24 ± 0,22: 0.20 ±0,19: 0,19 ± 0,19. respectively to 90, 150, 210. 270 and 330 days of age. These values suggest a small expected genetic gain from selection for this trait.