This paper reviews research findings relevant to the additive genetic improvement of growth rate and reproductive traits of commercially farmed fish and shellfish. Based on estimates of heritabilities and realized responses to selection, the possibilities for improving growth rate are very promising in many species. In salmonids the potential to improve age at maturity is also very promising, while little information is available concerning this trait in other species. The advantage of applying family selection to improve age at maturity is stressed.
In Atlantic salmon and rainbow trout both the phenotypic and genetic correlations between egg volume and egg number are large and positive, and body weight has a strong positive influence on both egg traits. There seems to be no strong unfavorable relationship between growth rate and age at maturity and growth rate and Louis Vuitton Chaussure Femme egg size in these species. More research is needed, though, to better understand both the phenotypic and genetic relationships between growth, survival and fecundity traits and age at maturity in fish and shellfish.
Fecundity traits should only be considered in a breeding program if the genetic correlation between egg size or egg quality with early survival Ceinture Lv Damier or growth rate is negative. It is, however, important to keep records of these traits to study whether or not Chaussures Louis Vuitton 2014 they are changing over a period of time.