Bighead Carp:
The natural habitat of this carp is the same as for the silver carp and it has also been introduced into many countries. Larvae of bighead carp feed mainly on unicellular planktonic organisms, nauplii, and rotifers.
Larger fry and adults go on feeding on various forms of plankton, mainly zooplankton.
The alimentary canal of this fish is much shorter than that of silver carp, due to its feeding habit based on zooplankton, rather than on phytoplankton.
The similarity in feeding habit between the bighead carp and the Indian major carp catla leads to a high degree of competition for food bet ween these 2 species when grown together in polyculture in the same pond.
Under favorable culture conditions, growth rate of fingerlings can reach 6.3 g.day- 1 and of adults as high as 14.7 g.day- 1 . Individual weight of bighead carp attains in these conditions 3.2 kg after 2 years culture and 10.7 kg after 3 years.
The age at first maturity of bighead is 3–4 years in South China (weight: 5–10 kg) and 6–7 years in North China (same weight). The fish spawns during monsoon in its natural habitat but does not breed naturally in captivity.
Common Carp:
Depending on various authors, the common carp is native of the temperate regions of Asia, especially of China or would be rather native of the rivers draining into the Caspian Sea and the Black Sea or originated from central Asia and was introduced in ancient times into China and Japan in the oriental region and into Greece and Europe through Rome.
The common carp has four subspecies and numerous varieties or strains. Among this amount of varieties, it can be found the “big belly carp” of the Kwantung and Kwangsi regions of China, the Indonesian orange-colored carp (Cyprinus carpio variety, Flavipinnis c.v.), and the mirror carp (Cyprinus carpio var. specularis) with its Aischgrunder (Germany), and Royale (France) varieties.
Common carp post-larvae start feeding on small zooplankton (Moina, rotifers, Cyclops, and nauplii). Ostracods, insects including chironomid larvae, Euglena, and Closterium are added when common carp fry reaches 20 to 100 mm long.
Common carp bigger than 10 cm feeds on decayed vegetable matter containing bottom dwelling organisms, mainly tubificids, mollusks, chironomids, ephemerids, and trichopterans. Common carp dig and burrow into pond dikes and bottoms, looking for organic mater: the fish takes in the mud from which digestible mater is sifted and the remaining rejected. This feeding habit results often in pond embankments deterioration and water turbidity.
The growth rate of common carp, depending on its culture conditions, is around 2 g.day- 1 on average. The age of common carp at first maturity ranges from 1 year (or even 0.5 year) in Tropical Asian countries (India, Indonesia, Thailand, and Malaysia) and in Israel, to 3–4 years in Europe. The average weight at maturity ranges respectively from several hundreds grams to 1.5-2.5 kg.
Spawning season can occur year round (tropical countries) or only during a given period (May- June in Europe, March-August in Israel, and March-June in South USA) depending mainly on the water temperature before and during breeding period. Common carp breeds naturally in its natural habitat, as well as in ponds and tanks. The eggs are adhesive and the fish requires adequate substrata for spawning purpose and attachment of eggs. The relative fecundity of common carp varies from 90 000 to 300 000 ova.kg-1 of female body weight.
Catla:
Catla is native of the freshwater sections of the rivers of northern India, Pakistan, Bangladesh and Burma. The species has been transferred into rivers of peninsular India and more recently to several countries of East and South East Asia.
Catla, as juvenile, feeds mainly on zooplankton (Crustacea) and as adult feeds for t wo thirds on zooplankton and for one third on algae. The feeding habit of the fish is mainly concerned with the water column but also with the bottom, attested by the occurrence of organic detritus, mixed with sand, mud and rooted aquatic plants in the gut.
Catla is the fastest growing of the Indian major carps. Under favorable culture conditions, catla can reach a weight of 3.2 to 4.1 kg after one year, 10.9 kg after 2 years, and 18 kg after 3 years.
Catla attains sexual maturity in ponds during the second year of life at an average weight of around 3.0 kg. The average relative fecundity ranges from 100 000 to 250 000 ova.kg- 1 of females body weight when brood stock is over 3 years old.
The spawning season of catla occurs from May to August in North and Northeastern India, Bangladesh, and Pakistan. In South Indian rivers, the breeding season is more fluctuant (May- October) and may occur t wice a year.
Rohu:
The natural distribution of rohu is the same as for catla and the fish has also been transferred into peninsular India and many tropical countries all over the continents. The feeding habit of rohu is based on plant matter including decaying vegetation.
The fish is a bottom and water column feeder and is much less adapted to take zooplankton than other Indian carps.
Fry and juveniles of rohu, up to 100–200 mm long, feed mainly on unicellular and filamentous algae, and rotting vegetation, the percentage of the latter increasing in larger fish.
Under culture conditions, rohu shows a very high growth potential though having a somewhat slower growth rate than catla. The best-recorded performances of rohu are reached 1.0 kg after one year and 2.6–5.4 kg after the second year of culture.
Rohu attains first sexual maturity at the end of the second year in ponds but it has been observed in India that the maturity can be performed in one year only (3–4 years in Bangladesh). The average weight at first maturity stands around 0.5 kg (length: 350 mm). The relative fecundity of rohu is reported to vary from 100 000 to 400 000 ova per kg of female body weight. The spawning season of rohu generally coincides with the monsoon, from June to September in most parts of the Indian subcontinent.
Authors:
Lionel Dabbadie and Jerome Lazard
