Growth Performance, Body Composition and Feed Digestibility of Liza parsia (Hamilton 1922) Exposed in Different Saline Waters

Abstract

The study was carried out in the Wet Laboratory of the Fisheries and Marine Resources Technology Discipline, Khulna University, Khulna, Bangladesh in 5 rectangular glass tanks ( each with length 0.4953 meter, width 0.3048 meter and depth 0.3429 meter) with two replications of each where the first tank was considered as control, C (0 ppt), the second as Treatment 1, T1 (5 ppt),the third as Treatment 2,T2 (10 ppt),the forth as Treatment 3, T3 (15 ppt) and the fifth as Treatment T4, T4 (20 ppt)to find out the rate of survivability, proximate composition in different salinity level as well as growth performance of gold spot mullet Liza parsia (Hamilton, 1822) ”. 48 fishes (average weight 4.22gm) were stocked in these tanks at two feeding rates 10% and 5 % of body weight. The fishes were fed at morning and afternoon in a day average food conversion ratios were found 0.78± 0.06, 1± 0.00, 0.69±0.06, 0.78± 0.22 and 1.035± 0.25 in C, T1, T2, T3 and T4 in five tanks respectively. Specific growth rate was 0.829± 0.10% in C, 1.162± 0.14% in T1, 0.744± 0.20% in T2, 0.736± 0.10% in T3, 0.605± 0.15% in T4 respectively. Average daily gain was found higher in T1 (0.059± 0.006g/d), than in C (0.042±0.008g/d), T2 (0.038±0.008g/d), T3 (0.037±0.004g/d) and in T4 (0.030±0.005g/d). Average survivability rate were found 100(%) in all groups. The relationships between the total length andbody weight of the species were found to be linear which indicate that weight of fish increased with the increase in total length. The R 2 values were (R² = 0.932), (R² = 0.880), (R² = 0.919), (R² = 0.961) and (R² = 0.845) respectively. Water quality parameters were also found better in T1 than that of T2, T3, T4 and C. The water quality parameters of the fish tanks were recorded as temperature 28-30.3ºC, p H between (7.21-7.64), dissolved oxygen 5.01-5.68 ppm and hardness 184.55-237.65. It was observed that feeding efficiencies and growth performances were better in T1 than that of the rest groups. The best growth was found from T1 and lower growth was found gradually in T4, T3, T2, and C in case of Liza parsia (Hamilton 1822). The present study revealed that Liza parsia can tolerate a wide range of salinity and also better growth could be possible even in freshwater. This research showed that 5 ppt was the ambient salinity for better growth. Further research should be carried out for better knowledge about salinity tolerance of Liza parsia and its effect on it to develop its production in our aquaculture sector. A field trial is needed to observe the culture potentiality in nature

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