Broodstock can be a population of animals maintained in captivity as a source of replacement for, or enhancement of, seed and fry numbers.
[3] Such conditioning is necessary to ensure the sustainability of aquaculture production,[4] and to increase the number and quality of eggs produced and control the timing of maturation and spawning.
[5] Management of the technologies for gamete production in captivity is one of the essential step for aquaculture that would ensure the growth to this sector.
Many species of captive fish are able to reach reproduction maturity in aquaculture conditions and gonadal growth occurs normally.
[6] Hormonal manipulation and acceleration of final oocyte maturation due to the economics of broodstock management is important.
This includes their size at maturity, method of reproduction, feeding behaviour and ability to tolerate adverse conditions[9] Farms also consider whether they grow their own broodstock or obtain them from natural populations.
Where natural populations are excluded, the farm can be considered a self-sustaining unit independent of external genetic influence.
[10] Pond-reared broodstocks are selected, often as immature juveniles, and grown out in suitable conditions to sexual maturity.
The feeding regime of broodstocks is species specific[10] and requires consideration of timing and composition of the food.
Managers can select for reproductive characteristics which influence the egg producing capability of individuals and increase fecundity by providing them with optimal environment and diets.
[5] Broodstock managers can use or select for traits such as fast growth rates or disease resistance over generations to produce more desirable fish.
[16] For example, a trout stock maintained as a closed population for 20 generations showed reduced number and size of egg production.
[20] Due to declines in the supply in the past 30 years,[20] New South Wales introduced a selection program in 1990 to breed faster growing stocks.
[23] Rainbow trout broodstocks are commonly manipulated to delay maturation and spawning time in order to provide eggs regularly and optimise supply.