Fish farming is carried out at largely in most countries of Asia and Europe. Crucian Carp is one of the freshwater fishes that dwell in the rivers, lakes and reservoirs. This is a fact sheet provided by the Food and Agriculture Organization of the UN which explains the methods that are adopted for the production of Crucian Carp.
Environmental and biological facts:
Crucian carp are usually sedentary type fishes that naturally propagate in different types of water bodies like lakes, rivers and reservoirs. They are basically omnivores generally feeding on filamentous algae, organic detritus, seeds and pieces of aquatic weeds and small benthic animals. But the larvae or the fry feed usually on zooplankton.
Artificial feed like pelleted feed, by-products from oil extraction and grain processing are also used in aquaculture. The main stimuli for reproduction are water level, rainfall and the temperature changes. The existence of aquatic weeds aids in spawning. They serve as the substrata for the eggs, which are normally adhesive. The average growth rate of a medium sized Crucian Carp is 1.25 kg.
The earthen pond culture is the mainly used system for rearing the Crucian Carp. But even rice paddies are used in countries like China.
Production cycle of Crusian Carp
Criteria for Pond preparation:
There are certain typical aspects for the preparation of the pond for the reproduction and nursing of Crucian Carp and getting them ready for the end of year carp Sale.
Generally earthen ponds of the size of 1.5-2.0 m deep and 0.07-0.2 ha, are used for farming of the Crucian Carp. Before the Crucian carp is introduced in the ponds, the ponds are treated chemically with quicklime to ensure the elimination of all the harmful organisms that hinder in the process of Carp hatchery. The quicklime that is used usually amounts to 900-1125 kg/ha.
Even the organic fertilizers like the green and the animal manure are used for increasing the biomass of the zooplankton that is the natural food organisms for the carp. These are applied 5-10 days prior to stocking. This also depends on the water temperature. The quantity of the organic manures used may be:
4500 kg/ha for green manure.
3000 kg/ha for animal manure.
However, when both are used, their quantity gets reduced.
Supply of seeds:
The major supply of seed for Crucian carp culture is derived from artificial spawning. There are also natural seeds available in various water bodies that aid in carp culture. Carassius carassius gibelio is the commonly cultured carp. This is produced through the method of gynogenesis with the Xingguo red common carp which is the male and the female Carassius carassius gibelio. All female off-springs provided by the assorted gynogenesis, have a growth rate of 30-40 percent, which is higher than that of the original fish. There are also various other strains and species of Crucian Carp cultured in different parts of China.
Usually matured and well selected brood stock is released into the spawning ponds, cages or tanks. Providing good substrata of palm leaves, plastic weeds, grass bundles and branches of fine trees, is very important in the water column where the spawning is carried on and the egg attachment takes place. Eggs can also be hatched in earthen ponds after treating them chemically. They require the eggs to be moved and fixed in the water column in the ponds along with the substrata.
Eggs hatch better in running water (jar or raceway). The eggs along with the substrata are merely hanged in the water column. The eggs along with the substrata can also be placed in jars or raceways, for hatching. The adhesiveness in the eggs is removed by blending with the clay solution before stocking. Later, the fry or hatchlings are shifted to the nursery ponds when they become capable to feed actively and swim well.
Sometimes hormonal injections are also given for the synchronous spawning of the fishes. Such hormonal injections are optional only. The fishes spawn well even without using them.
Nursery stage continued on our blog website