Research Symposium-2016

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Browsing Research Symposium-2016 by Author "Adikari, A.M.A.N."

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    Strategies to Reduce Larval Cannibalism of Pangasius stitch!
    (Uva Wellassa University of Sri Lanka, 2016) Thilakarathna, W.M.W.S.; Epasinghe, E.D.M.; Karunaratne, T.A.D.W.; Adikari, A.M.A.N.; Liyanage, N.P.P.
    Ornamental fish industry is the most significance income earning approach in Sri Lankan economy. Pangasius sutchi (Thai pangus) is considered as the most popular ornamental fish species. In their early larval stage, they show cannibalistic behaviour which leads reduction of population. Then experiment was conducted to reduce the larval cannibalism of larvae within first 72 hours because it has been identified as the critical period of their cannibalistic behaviour. Therefore several types of feed, feeding frequencies and stocking densities were tested. We investigated the effect of two different types of feed(Artemia and Moina),three different feeding frequencies (3hr,4hr,5hr)and three different stocking densities(60.90.120)one square feet can hold 80 larvae and 22"x 10x 10glass tank can hold approximately 94 P.sukhi larvae. Each tank was randomly assigned to one of the treatment. At the end of the experiment numbers of survivals were calculated to determine the cannibalism rate. Five fish from each tank were sampled to measure body length. Then numbers of average body length were recorded. Data were statistically analized by using MINITAB 17 software. Significance levels were calculated to determine whether there is any relationship or not. Results showed that the feed types were not significantly (p>0.05) affect the survival rate and it only affected the body length. Feeding frequency was significantly (p<0.05) affected the survival rate and not affected the body length. And also results showed that stocking density affected the survival rate significantly (p<0.05) and not affected significantly for body length of larvae. Final results indicated that highest mean survival rate was recorded with 60 stocking density whereas lowest survival rate was recorded in 120.highest mean body length was recorded with the Artemia feeding with 3hour feeding frequency. Keywords: Cannibalism, Feeding frequency, Stocking density, Artemia, Moina