SELECTION FOR GROWTH IN THE GILTHEAD SEABREAM, SPARUS-AURATA L

Despite extensive mariculture of the gilthead seabream, Sparus aurata, in the Mediterranean basin, there are no heritability estimates for g rowth in this or any other cultured warm water marine teleost, and so it is unknown whether selection for faster growing fish would result i n genetic improvement. In the present study, we estimated heritability for weight in the Eilat hatchery strain of S. aurata, using single-ge neration mass selection procedures. Down, control, up and extreme up ( ''jumper'') selected male groups were crossed with randomly chosen uns elected females. Progeny groups were cultured in replicates under comm unal and separate rearing conditions. Heritability estimates for weigh t varied, but overall were positive and of a moderate magnitude.