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Several methods exist for propagating the common carp. They are all based on its reproduction biology and they may be grouped into these three categories:
Natural propagation, no gonadotropin hormone
treatment but environmental manipulation, if necessary.
Semi-artificial propagation, one injection of gonadotropins to
induce ovulation/spawning.
Artificial propagation, two injections of gonadotropins, stripping of sexual products, artificial fertilization, incubation of the fertilized eggs and larval rearing.
Adult fish which have developed dormant eggs are stocked in these ponds at the average rate of 3-4 fish per hectare, 2-3 males for each female.
Breeding success is very dependent on weather conditions which cannot be controlled; over- or understocking of the pond with juveniles may result.
(1) A small pond (100-1000 m²) is specially prepared. A ditch 12 m wide and 60-80 cm deep is dug along the banks of the pond around a central platform covered with short grass. At maximum water level, 30-50 cm water will cover this platform. When the water temperature becomes suitable, the pond ditch is filled with filtered clean water.
(2) One or two sets of breeders each consisting of two females and three males are then stocked. They are kept there for a few days, in a gentle continuous flow of water. (3) Then the water level is slowly raised, flooding the grassy area. This operation usually triggers the breeders into vigorous spawning.
(4) A day later, the breeders are carefully removed from the pond by lowering the water level slightly and netting them in the ditch. The presence of eggs sticking to the submerged grass is confirmed.
(5) After hatching, the larvae are easily observed using a white plate.
When the fry reach 12-15 mm about 10 days later, they are harvested by draining the pond.
(1). These spawners are immediately stripped (2). The eggs are artificially fertilized (3). They are then transported to a suitable place for incubation and hatching, such as, for example, a nearby hatchery (4).
The hatched larvae swim freely out into the water (4).
Instead of baskets, other containers such as cloth enclosures (hapas) and wooden boxes covered with mosquito netting may also be used.
The injected spawners are then transported (2) and stocked in newly filled grassy ponds (3). Spawning usually takes place one to two days later, depending on the water temperature (4). This technique may be applied, for example, in large ponds or in smaller Dubisch ponds, see preceding methods.
The injected carp breeders are put into the hapas and spawning occurs within a few hours (2). The breeders are then removed (3) and the larvae hatch in the hapas (4).
The injected breeders (2 males for each female) are stocked in the spawning ponds or boxes (2).
Spawning takes place and the eggs are found sticking to the kakabans (3). The kakabans are then removed from the spawning ponds and placed for incubation either directly into a pond (4) or first into wire-meshed boxes (5), the larvae being later stocked in ponds (6).
You will require 1-1.5 m² of kakaban per female spawner.
As soon as they begin to feed, the early fry are taken away to rearing ponds.
(1) The need for male spawners is reduced by 4-6 times.
(2) During incubation, it is possible to protect the eggs against
parasites and diseases, (3) bad weather conditions, and (4)
predators. (5) The newly hatched larvae may also be better
protected against their enemies and (6) their survival is further
enhanced through controlled first feeding. (7) The stocking of
early fry in well-prepared ponds ensures better growth and better
survival.
