Editing Selective breeding (section)

===Quality traits in aquaculture===
Aquaculture species are reared for particular traits such as growth rate, survival rate, meat quality, resistance to diseases, age at sexual maturation, fecundity, shell traits like shell size, shell color, etc.
*'''Growth rate''' – growth rate is normally measured as either body weight or body length. This trait is of great economic importance for all aquaculture species as faster growth rate speeds up the turnover of production.<ref name=g83/> Improved growth rates show that farmed animals utilize their feed more efficiently through a positive correlated response.<ref name=g85/>
*'''Survival rate''' – survival rate may take into account the degrees of resistance to diseases.<ref name=g85/> This may also see the stress response as fish under stress are highly vulnerable to diseases.<ref name=g83/> The stress fish experience could be of biological, chemical or environmental influence.
*'''Meat quality''' – the quality of fish is of great economic importance in the market. Fish quality usually takes into account size, meatiness, and percentage of fat, color of flesh, taste, shape of the body, ideal oil and omega-3 content.<ref name=g85/><ref>{{cite journal|last1=Joshi|first1=Rajesh|last2=Woolliams|first2=John|last3=Meuwissen|first3=Theo MJ|title=Maternal, dominance and additive genetic effects in Nile tilapia; influence on growth, fillet yield and body size traits|journal=Heredity|volume=120|issue=5|pages=452–462|date=Jan 2018|doi=10.1038/s41437-017-0046-x|pmid=29335620|pmc=5889400|bibcode=2018Hered.120..452J }}</ref>
*'''Age at sexual maturation''' – The age of maturity in aquaculture species is another very important attribute for farmers as during early maturation the species divert all their energy to gonad production affecting growth and meat production and are more susceptible to health problems (Gjerde 1986).
*'''Fecundity''' – As the fecundity in fish and shellfish is usually high it is not considered as a major trait for improvement. However, selective breeding practices may consider the size of the egg and correlate it with survival and early growth rate.<ref name=g85/>