WWW.WAS.ORG • WORLD AQUACULTURE • JUNE 2016 59 mixed with groundnut oil cake or rice bran. However, better breeding performance can be obtained by feeding a compound pelleted feed made from a mixture of fishmeal, groundnut oil cake, soybean meal and rice bran with vitamins and minerals, containing 32 percent protein, at 2-3 percent of body weight daily. Induced Breeding Operation Magur matures and breeds from June to August when there is ample accumulation of rainwater in confined water bodies, coupled with favorable temperatures and other natural conditions in the environment. The fish digs crevices below the bunds of ponds to deposit eggs. The fish is considered monogamous. Breeding activity and natural spawning continues for 10-12 h or more. Researchers and some farmers, in occasional cases, exploit the possibility of natural spawning by releasing injected or non-injected broodfish in artificially created simulation conditions, aiming not to kill the male during hatchery breeding operations. Simulating conditions of water flow by adding water through shower heads gives the impression of rainfall. Artificial crevices for spawning are provided in breeding tanks. Natural spawning in tanks, ponds and paddy fields has also been attempted where rainwater accumulates or even in hatchery conditions during monsoon days. Results derived from these trials registered varying degrees of success. Release of fewer eggs in a batch after a long waiting period is observed on many occasions. The incomplete release of eggs has become a constraint for mass-scale seed production, although some claim better growth of larvae produced by this breeding technique. This may not be a procedure to depend on to produce a huge supply of seed to farmers. Researchers have shifted to concentrate on induced breeding for mass-scale seed production in hatchery conditions. When gravid females have round and bulging abdomens with pinkish button-shaped genital papilla and males have pointed papilla, they are considered suitable for induced breeding operations in India is well known for carp aquaculture, related to an intensive research effort and then massive adoption by farmers; carp remains a mainstay of Indian aquaculture. Next to carps, catfishes are considered to be potential cultivable species. Among these, Clarias batrachus is a preferred medium-sized catfish for pond culture. Clarias batrachus, popularly called “magur” in India, is in high demand for its taste and therapeutic value. Magur fetch a higher market price than carp and are sold fort US$ 4-8/kg in India. Magur generally is stocked at densities that are 5-10 times greater than carp stocking densities because its hardy and air-breathing nature is favorable for high-density culture. Researchers have worked intensively on magur biology, captive production and dissemination of culture technology under the “All India Coordinated Project on Airbreathing Fishes.” Breeding failure, early larval mortality and a lack of suitable larval feed are some of the bottlenecks for mass seed production. The ICAR-Central Institute of Freshwater Aquaculture (CIFA), Bhubaneswar and other research institutions developed breeding and seed production technology of magur. A brief account of magur hatchery technology developed by ICAR-CIFA is discussed here. Broodstock Management Maintenance of healthy broodfish is a prerequisite for successful seed production in captivity. Magur attains maturity in the first year. Broodfish of 100-150 g weight, commonly preferred for breeding (Fig. 1a), are raised in earthen ponds at 2-3/m2. Sometimes, broodfish are transferred to soil-based cement tanks prior to the monsoon season. This reduces difficulties in collecting broodfish during the rainy season and facilitates easy maintenance of water quality through water exchange when required to improve maturity. Often, hatchery owners collect broodfish from ponds and maintain them in nylon hapa nets fixed in the ponds. Also, some farmers purchase broodfish during monsoon months and keep them in big silver containers for breeding, a condition that invites breeding failure in many cases. Farmers formerly fed broodfish with ground low-cost fish or fishmeal Recent Trends in Breeding and Seed Production of Magur in India S.K. Sahoo, S. Ferosekhan, S.S. Giri and S.K. Swain (CONTINUED ON PAGE 60) FIGURE 1a. Broodfish of magur. FIGURE 1b. The genital papilla of gravid magur that are suitable for breeding.
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