Genetic variation in growth parameters until commercial size in diploid and triploid freshwater rainbow trout ( Oncorhynchus mykiss) and seawater brown trout ( Salmo trutta)

Variation in growth performances was analysed in 16 half-sib diploid and triploid families (from different sires) of rainbow trout ( Oncorhynchus mykiss) and brown trout ( Salmo trutta). At 1 year old stage (300 g) in rainbow trout, and 1.5 year old stage (320 g) in brown trout (3 months after transfer to seawater), 20 to 25 fish per family were individually tagged. Individual growth performances were followed, respectively, in freshwater for rainbow trout and seawater for brown trout up to their usual commercial size of 900 g and 3 kg, respectively. In rainbow trout, a significant genetic variability was observed among families in initial body weight, length and condition factor ( P