Nagaland, known for its picturesque landscapes, is now making waves in aquaculture, with the common carp (Cyprinus Carpio) emerging as a pivotal species in the region’s composite farming systems. The common carp has not only become a dominant fish species in rice-fish farming but is also proving its adaptability in hilly and cold regions where major carps face challenges.
Common carp, recognized for its ability to survive cold winters, endure low oxygen concentrations (0.3-0.5 mg/litre), and even supersaturation, has become a linchpin in Nagaland’s aquaculture practices. The Aqua Nest Murrel Hatchery, operating since 2020, has played a crucial role in promoting the cultivation of common carp, making it an essential species for the local community.
Known for its versatility, common carp are primarily bottom dwellers but exhibit a unique behaviour of searching for food in the middle and upper layers of water bodies. In the polyculture system, carps can achieve an impressive body weight of 0.6 to 1.0 kg within a single season.
Food and Feeding Habit:
Omnivorous by nature, common carp exhibit a preference for water insects, insect larvae, worms, mollusks, and zooplankton. Additionally, they consume aquatic and terrestrial plant stalks, leaves, seeds, and decayed aquatic plants. Supplementary diets such as oil cake and rice bran are also readily accepted.
Breeding and Seed Production:
Common carp breeding is typically conducted in confined water, with spawning occurring in shallow, weed-infested areas. Breeding operations take place in hapas, cement tanks, or small ponds, utilizing submerged aquatic plants as substrata for egg laying. The resulting fry, aged 4 to 5 days, are then stocked into nursery ponds.
Broodstock Maintenance and Selection:
Before the breeding season, healthy male and female common carp are segregated and placed in separate ponds or tanks. Artificial food, a blend of oil cake and rice bran in a 1:1 ratio, is fed to breeders at 2-3% of their total body weight. The selection of breeders is a meticulous process conducted in condition hapas, ensuring the health and readiness of the brooders.
Breeding Operation:
Hapas or cisterns are commonly used for breeding operations, with male and female common carp stocked in a 1:1 ratio by weight. The water used for breeding must be fresh and free of algal bloom. Adhesive eggs are collected using materials such as Hydrilla, Najas, palm or coconut fibers, and synthetic fibers of gunny bags.
Spawning occurs mainly during the night to early morning, with the breeders introduced into hapas or tanks in the evening. After spawning within 6-10 hours, the brooders are released into the pond. Fertilized eggs, examined for pale dirty yellow color, are then transferred to well-prepared, predatory-free nursery ponds for hatching.
Hapa Hatching:
Hapa hatching, a pivotal phase in the breeding process, involves a double-walled enclosure fixed in the pond. The outer hapa, made of bolting cloth, and the inner hapa, made of mosquito net cloth, facilitate uniform egg distribution. Hatching times range from 36-72 hours, with hatchlings escaping to the outer hapa. Once hatching is complete, the inner hapa containing egg shells is removed.
Breeding Through Hormone Administration:
Stripped spawning involves inducing selected males and females with carp pituitary gland extract or inducing agents like ovaprim, ovatide, or WOVA-FH. The egg-milt mixture is treated to remove adhesiveness, ensuring free-floating eggs for incubation.
Spontaneous spawning is conducted in earthen ponds or cement cisterns, with egg collectors provided for attachment. Female brooders are induced with synthetic hormones and released into spawning pools with synthetic fiber. After breeding, broods are removed, and the eggs are incubated until hatching occurs.
The success of common carp farming in Nagaland highlights the region’s commitment to innovative aquaculture practices, with Aqua Nest Murrel Hatchery leading the way. As the community reaps the benefits of sustainable fish farming, common carp remains a crucial species in Nagaland’s thriving aquaculture landscape.