SALIENT BIOLOGICAL CHARACTERISTICS OF SOME SELECTED CARPS

Submitted byNazmul Ahmed OliReg: 12-05-2835Level: 2Course code: FBE-201

Carps:The species of fishes which belongs to family Cyprinidae under the order Cypriniformes is called carps. Mainly three types of major carps are cultured in our country. Indian Major Carps: Rui (Labeo rohita), Catla (Catla catla), Mrigal (Cirrhinus mrigala).Chinese Carps: Grass Carp (Ctenopharyngodon idella), Silver Carp (Hypophthalmichthys molitrix), Bighead Carp (Aristichthys nobilis).European Carps: Common Carp (Cyprinus carpio).

Bighead Carp: (Aristichthys nobilis)

Food Habit:Bighead Carp is filter feeder, mostly zooplankton feeder throughout its life under natural conditions. In culture, bighead carp will also accept artificial feed, such as the by-products from grain processing and organic detritus, in addition to natural food.

Growth:High growth rates, reaching 0.75-1.5 kg in the 2nd year and 3-4 kg in the 3rd year.It can reach a maximum weight of 40 kg. In culture conditions, growth rate would depend on rate of stocking, food availability, competition with other species and environmental conditions

Fecundity:Fecundity ranges from 288,000 to over 1 million based on size of female. The fecundity is 126 eggs per gram of body weight. Breeding season & Spawning:The fish breeds during monsoon months in the flowing waters in its natural habitats, in river, but does not spawn naturally in a static waters of pond and tanks. Spawning temperature 22–30 C in native range

Maturity:The environmental factors such as temperature exercises maximum effect on the maturity of bighead carp.Bighead Carp: (Aristichthys nobilis)

Common Carp:(Cyprinus carpio)

Food Habit:Common carp are mainly bottom dwellers but search for food in the middle and upper layers of the water body. They are omnivorous, with a high tendency towards the consumption of animal food, such as water insects, larvae of insects, worms, molluscs, and zooplankton.

Growth:Best growth is obtained when water temperature ranges between 23 °C and 30 °C. The fish can survive cold winter periods. Salinity up to about 5‰ is tolerated. The optimal pH range is 6.5-9.0.

Maturity:The maturity period of common carp is slightly shorter. Age at first maturation: 2-3 years (males), 4-5 years (female) .The spawning starts when the water temperature is 17-18 °C. Fecundity:

Total fecundity ranges from 90,000 to 300,000 ova/kg live weight of the female .Egg diameter 1.0-1.5 mm

Breeding season & Spawning:Common carp usually breeds in rainy season, generally April-June in temperate climates. They may spawn throughout the year in tropical areas of India, with peaks in January-March and July-August.

Common Carp:(Cyprinus carpio)

Food Habit:The fry of catla are feeding mainly on zooplankton such as rotifers and cladocerans. Adults feed only in surface and mid-waters; they also are planktophagous, with a preference for zooplankton, mainly crustaceans, rotifers, insects and protozoa, as well as a considerable share of algal and plant material.

Growth:In natural waters, catla attains a length of 295 mm in the 1st year,514 mm in the 2nd year, 716 mm in the 3rd year.323 mm in the 4th year. .

Catla:(Catla catla)

Maturity:Catla attains maturity in its second year, Alikunhi mentioned that in ponds catla becomes mature when 22 months old.

Fecundity:Its fecundity generally varies from 100 000-200 000/kg BW, depending on fish length and weight. Breeding season & Spawning:This fish Breeds during summer and rainy season. The spawning season coincides with the south-west monsoon in north-eastern India and Bangladesh, which lasts between May and August.

Catla:(Catla catla)

Food Habit: Rohu is bottom column feeder. Its food comprises crustaceans and insect larvae in early stages . The percentage composition of food of L. rohita may be filamentous algae 15%, rotting vegetation 55%, rotifers & protozoa 2%, crustaceans 8%, mud and sand 7%. L. rohita takes small percentages of mud which contains organic matter and various salts.

Growth:Under culture condition, rohu is very quick growing fish having relatively a little slower growth than catla. A growth of 35-45 cm can be expected in the first year in a well-managed pond.

Rohu:(Labeo rohita)

Maturity:Rohu attain maturity at the end of 2nd year. It breeds naturally during the southwest monsoon in shallow inundate marginal water, extending from April to September.

Fecundity:The fecundity of rohu is reported to vary from 226,000 to 2,794,000 depending upon the length and weight of the fish and weight of the ovary.

Breeding season & Spawning:The Breeding season of rohu is April to September. The spawning season of rohu generally coincides with the southwest monsoon, though it be somewhat variable in different parts of India. Spawning occurs in shallow and marginal areas of flooded river. It is reported that rohu matures in Bangladesh at the age of 3-4 years.

Rohu:(Labeo rohita)

Mrigal:(Cirrhinus cirrhosus)

Food Habit: Mrigal is detritus eater with a narrow range in food variety. It is a bottom feeder subsisting mainly on decayed vegetation and small animals. The stomach contents include algae 20%, bits of higher plants 30%, protozoa 15%, crustacea 25%, mud and sands 10%. It usually does not take worms, insects, mollusks and fishes.

Growth:Mrigal normally attains 600-700 g in the first year, depending on stocking density and management practices. The rearing period is usually confined to a maximum of two years, as growth rate reduces thereafter. However, mrigal is reported to survive as long as 12 years in natural waters.

Maturity:Maturity is attained in two years in captivity. Mrigal needs a fluviatile environment for breeding it does not breed in ponds. However, captive breeding in hatcheries has been made possible through induced breeding by hypophysation and the use of synthetic hormones.

Fecundity:Mrigal is a highly fecund fish. Fecundity increases with age, and normally ranges from 100 000-150 000 eggs/kg.

Breeding season & Spawning:The spawning season depends upon the onset and duration of the south-west monsoon, which in India, Bangladesh extends from May to September. Mrigal usually breeds at 24-31 ºC.

Mrigal:(Cirrhinus cirrhosus)