Photo credit: Bishnu khanal (Nepal)
Review: Bishnu khanal and Abdel Rahman El Gamal (Founder of the website)
It is quite common fish farmers may adopt natural or semi-natural (or semi-artificial) spawning systems as long as found technically and economically feasible. The inserted photo presents an example of the pond spawning of common carp (Cyprinus carpio) in Nepal using “kakabans”.
The spawning takes place naturally whenever particular conditions are available especially temperature and adequate water rise. Assuming, the broodstock have been properly selected, the spawning would still need grasses or similar egg collectors in order for the laid eggs to stick to bearing in mind the adhesive nature of carp eggs.
“Kakabans” that are known and widely used in Nepal and Indonesia are shown in the inserted photo. Kakabans are made of dark horse-hair-like fibers of the indjuk plant (Arenga pinnata andArenga saccharifera) which are cleaned and arranged in layers whereas bamboo planks are used to frame the kakabans.
For the spawning procedures, Kakabans are kept in a floating position a little under the water surface, propped up on bamboo poles. The spawned pond is filled with clean water at the correct temperature the same day as the fish are introduced after being injected with the pituitary gland extract. For guidance, about 1 to 1.5 m2 of kakabans will be needed per a common carp female.
As soon as the eggs are seen on the kakabans, the egg-laden kakabans are transferred to hatching ponds in which embryos hatch. Care should be taken to ensure that the eggs remain fully submerged in about 8-10 cm of water. Common carp hatchlings stay in the hatching pond for about three weeks before they are collected for further use.
