44 SEPTEMBER 2014 • WORLD AQUACULTURE • WWW.WAS.ORG fed for better growth. The physicochemical parameters of clownfish larvae and juveniles was measured and maintained as follows: temperature (26 ± 2 C), salinity (3235 ppt), pH (7.8-8.5) and dissolved oxygen (5.0-6.5 mg/L). Ammonia was maintained at <0.01 mg/L in rearing water, which was determined manually. Daily water exchange (30-50 percent) was carried out to maintain ammonia levels and prevent microbial growth using UVfiltered seawater in the tanks. Juveniles were reared following standard practices for up to three months, attaining a length of > 3 cm, which were suitable for market (Fig. 1). At one month, juveniles were fed with mashed fish, tuna eggs and commercial pellets. The hatchery practice was followed for production of five species of clownfish (Amphiprion nigripes, A. clarkii, A. percula, A. ocellaris and Premnas biaculeatus). An average value of 65 percent survival was achieved. Technology Transfer to Islanders The “Hands-on Training Programme on Marine Ornamental Fish Culture,” including breeding and rearing was organized for local island communities (Fig. 3) for their income generation and to conserve coral reefs and wild fishes. The training covered the following topics: • water filtration and circulation methods, • broodstock development, breeding and larval rearing, • live feed culture (stock and mass), • feeding of brooders, larvae and juveniles, • disease diagnosis and treatment methods, • packing and transportation, • formulation of inert feeds, • marketing strategies, • homestead hatchery design, • financial guidelines and management. The CMLRE Marine Ornamental Fish Hatchery at Agatti Isalnd, Lakshadweep has developed a demonstration hatchery and technology transfer unit for all categories of islanders (fisheries officers, graduate students and fishing community members). The unit also serves as a facility to create sustainable fisheries awareness among schoolchildren and other islanders. The smallconical ovipositor becoming visible. Clownfish females usually deposited capsule-shaped eggs, starting at noon, and males then spread milt over the eggs, a process with a duration of nearly 30 min. The fecundity of a healthy fish was 300-700 eggs and males always guarded fertilized eggs by fluttering the pectoral fins. Eggs turned from dark orange to black and the tip of eggs appeared silvery-black at hatching. Embryonic development could be divided into 26 stages, based on morphological characteristics. Larvae Rearing. Eggs hatched after sunset on the eighth day after fertilization and larvae could utilize yolk reserves for up to 8-10 hr. Eggs hatched after sunset and before midnight. At early morning, larvae were collected in a glass bowl and transferred to prepared larval rearing tanks. Rectangular, clear glass tanks (100-L capacity) were used for larval rearing. The photoperiod of the larval rearing tanks was maintained at 14 hr light and 10 hr dark, using 20-W fluorescent bulbs. Physico-chemical parameters in larval tanks were maintained the same as in broodstock tanks. About 30 percent of the tank water volume was replaced with UV-filtered seawater daily. Following Ajith Kumar et al. (2012), algal-enriched rotifers were selected for larval feeding to attain sustainable hatchery production and good survival rates. Small (S-type) rotifers Brachionus plicatilis was enriched with algae Nannochloropsis spp. for three hours prior to feeding to fish larvae. The algal stock culture was maintained using Convey & Walne’s medium and outdoor mass culture by commercial fertilizers (Fig. 2). The initial feed for larvae was provided within 6-7 hr after hatching. Rotifers were fed to clownfish three times per day for 10 days at a density of 7-10/mL. Metamorphosis of larvae among the five species of clownfish showed little variation (± 3 d) to attain the same color as mature fish. Juvenile Rearing. Ten days after hatching, larvae were fed with newly hatched Artemia naupili, followed by algae-enriched Artemia, three times per day up to 40 days after hatching. After this period, well-mashed fish meal or clam meal of >500 µm size were FIGURE 1. Juveniles of five different types of clownfish for commercialization produced at Agatti Island, Lakshadweep. Amphiprion nigripes Amphiprion percula Amphiprion clarkii Premnas biaculeatus Amphiprion ocellaris
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