“…The most frequently studied trait is growth, which represents almost 93% of genetic parameter estimations in marine mollusks (Dégremont, 2003). A large number of studies found significant heritability for juvenile and adult growth among a variety of clam, mussel, oyster and scallop species (Lannan, 1972;Haley et al, 1975;Wada, 1984Wada, , 1986Wada, , 1994Mallet et al, 1986;Strömgren and Nielsen, 1989;Hilbish, 1990, 1991;Newkirk, 1990, 1991;Crenshaw et al, 1991;Hadley et al, 1991;Hilbish et al, 1993;Jarayabhand and Thavornyutikarn, 1995;Toro et al, 1995;Crenshaw et al, 1996;Toro and Parades, 1996;Ibarra et al, 1999;Brichette et al, 2001;Ernande et al, 2003;Zheng et al, 2004). Even though survival is usually considered a trait difficult to improve through genetic selection (Gjedrem, 1985), a number of papers have reported a significant genetic basis for survival in C. gigas (Beattie et al, 1980;Hershberger et al, 1984, Soletchnik et al, 2002Ernande et al, 2004).…”