Browsing by Author "Nehemia, Alex"

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    Survival and growth rates of Pangani River’s tilapia in sea water for mariculture development
    (University of Dar es Salaam, 2011) Nehemia, Alex
    The potential for Tilapia zillii and Oreochromis urolepis culture in marinewaters was evaluated by determination of the survival and growth rates in full strength sea water (FSSW) at 35%o. For the study fingerlings were collected from Pangani by using seine nets and reared in 1m 3 concrete ponds where salinity for their growth media was changed to 35%o at the rate of about 2%o per day. Fingerlings were fed twice daily using commercial fish feeds (White Rose floating type), initially at a rate of 5% af their total body weight (TBW) and two weeks later at 10% of their TBW. The growth rate was recorded once a week except for handling control fingerlings which were recorded at the beginning and at the end of the experiment. The average Height gain (g/week), percentage weight gain (%/week) and specific growth rate (SGR, %/day) during acclimatization period in fresh water (FW) and acclimatization saline Hater (SW) in the bracket for O. urolepis urolepis were found to be 1.06 (2.5), 24.6 (6.98) and 2.86 (0.93) respectively and in T zillii 1.59 (2.30), 19.11 (13.50) and 2.47(1.77) respectively. After acclimatization in freshwater (FW) and full strength sea water (FSSW) at 35%o (in bracket) for O. urolepis urolepis were found to be 1.88 (1.86), 22.96(4.09) and 2.92(0.58) and for T. zillii 0.66(1.32), 5.09 (5.44) and 0.71 (0.75), respectively. There was no signifcance difference (p >0.05) in SGR between the two species in FSSW at 35%o. The survival rates in FW and FSSW at 35%o (in bracket) for O. urolepis urolepis and T. zillii were 100% (100%) and 89% (96%), respectively. This study shows that if managed well T. zillii and 0. urolepis urolepis can survive and grow in FSSW at 35%o.