We know that carp don’t spawned in pond. But they have eggs. Why they don’t spawned in pond? Is that only for current? My another question is in which stage the egg development stop?
Under pond conditions, the carps do not spawn, although they attain maturity. This is due to the fact that the pituitary gonadotropic hormones which induce spawning are not released in sufficient quantities from the pituitary gland (hypophysis) to the general blood circulation so as to trigger spawning.
Female carps which fail to spawn, regressing of gonads or resorption of ovarian eggs occurs at the end of breeding season. The oocytes failing to release eggs, undergo serous changes and are known as atreotic follicles. The enclosed eggs lose their shape the vitelline membrane breaks at various positions and, after more disintegration, finally disappears.