Gonad development, growth, survival and quality traits in triploids of the protandrous hermaphrodyte gilthead seabream Sparus aurata (L.)
Haffray, P. | Bruant, J.S. | Facqueur, J.M. | Fostier, A.
The effect of triploidy on the protandrous hermaphrodite gilthead seabream, Sparus aurata, was evaluated from 2 g to 1347 g (42 months old). No difference of growth was recorded until 484 g (17 months old), 2n and 3n being all males. From 20 to 42 months old, the 3n exhibited a lower growth, the difference increasing to 15.3% at the end of the experiment. At the two reproductive seasons studied, 3n matured as males. The 2n and 3n males had the same weight throughout the experiment. It is postulated that the 2n's advantage is mainly due to the occurrence of their feminisation, the 2n females presenting a significant better growth. Out of the breeding seasons, the 3n presented higher gutted yields (from 0.5% to 2%) and a lower level of lipid concentration in the muscle (from -7.5% to -17.5%). The fillet of the 2n females is more fatty than the fillets of the 2n and 3n males. This study demonstrated that until the common commercial weight (480 g), 3n present the same growth as 2n and do not exhibit a difference in survival, processing yields and quality traits. For bigger sizes, 3n are lower performers in growth but are leaner and have a better gutted yield. As no spawning behaviour was observed in this land based farm, these results need to be evaluated in sea cages in which breeders spend 3-4 months a year in spawning.
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