"The Spawning Carp
Carp tend to spawn between May and July, this coincides with the closed season in the UK, but alas the carp require a period of sustained temperature between 18-24 degrees celsius and in the UK this period is not always within the closed season and often after it. A single female carp can produce up to 1 million eggs when it spawns dependant upon its size, maturity and environment. Most of the eggs are eaten by other predators in the form of insect larva, fish (including carp), birds, crayfish etc. The eggs that do manage to hatch into carp fry then have an uphill struggle to survive, avoiding other fish like pike and perch for example and many birds. After this they then have to cope with their first winter, which is where many of the surviving fry lose the battle and succumb to the cold.
But above all this, there will still be many thousands of carp that do survive, and the reason for the carps massive egg count is natures way of ensuring that some will always survive their first year, by which time the carp will start a rapid growth regime, trying to become large enough, quickly enough to stop the predators attacking and devouring it.
During spawning the male carp will develop tubercles on its head and gill plates, they look like small whitish bumps that have been scattered over them as if from a salt shaker. The females will be very fat due to the amount of spawn she will be carrying.
More often than not, there will be large numbers of male carp chasing, hassling and bumping into the females a day or so before she releases her eggs, with the chasing, hassling and bumping getting steadily more vigorous and aggressive the closer she is to laying her eggs.
Watching carp spawn is a spectacular sight to behold, although it can seem to be quite rough and animalistic at times. The mating carp will seem to be fearless as they battle to further their species in the warmer, shallower and weedier parts of the lakes, ponds and rivers, ignoring almost everything else around them (including people) in their quest to reproduce. It is not unknown to find a carp stranded outside of the lake/pond after spawning, due to the hectic splashing, crashing and jumping that accompanies the spawning ritual." - Sursa:
http://www.carpkrazy.com/carp-fishing-facts.html
