42 MARCH 2018 • WORLD AQUACULTURE • WWW.WAS.ORG once per year during the monsoon season (June-August), with a peak in July. From October to January pabda are in stages I and II of maturity. Most males mature from late March to May while females are only in stage I and II at this time. Fully ripe females are observed from May to the end of July. Feeding behavior is erratic during the maturation and spawning season. Broodstock management The success of breeding depends on a sufficient amount of quality broodfish. Broodfish are selected by sex and held in separate ponds. An average weight 150-200 g is good for breeding. Broodfish ponds should be 0.2-0.5 ha and 1-1.2 m deep (Fig. 1). Broodfish ponds and tanks should be covered with netting. Pabda broodfish should be fed daily with a 35 percent crude protein pelleted feed. In certain locations or for various reasons, it is not always possible to obtain and provide a high-protein pelleted feed. Thus, to provide an equivalent level of crude protein, a mixture of mustard oil cake, fishmeal, rice bran, and wheat flour can be pulverized and fed in the form of a dough. Broodfish condition should be examined periodically. Broodfish are harvested by reducing the pond water level during the breeding season. Identification of male and female broods is based on some external features (Table 2). Selected broodfish can be held in fiberglass tanks with continuous water flow for a day to allow evacuation of gut contents. Male and female fish are held in separate tanks and are not fed. Constant water flow is maintained to ensure proper aeration. Handling of fish should be done very carefully to avoid possible injury and secondary infection. Induced spawning After gut evacuation, a single injection of inducing hormone (e.g. Ovatide, OvaFH, Gonopro, Ovasis) should be administered to all broodfish. Fish are injected intramuscularly above the lateral line towards the dorsal fin using a 1-mL syringe. The needle is inserted at an angle approximately 30° from the head (Fig. 2). Injected spawners are kept separately in containers to avoid disturbances and self injuries. FIGURE 1. Earthen ponds for rearing of pabda broodstock. FIGURE 2. Administration of spawning inducing agent. Note size of syringe (1 mL) and proper angle of injection. FIGURE 3. Stripping ovulated eggs from pabda female broodfish. FIGURE 4. Fertilization of eggs by activation of sperm with water, accompanied by mixing sperm and eggs with a feather.
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