| dc.description.abstract | Tilapias are among the most important aquaculture species in the world, the adaptability and tolerance to a wide range of environments has resulted in a rapid expansion of tilapia farming. However, the expansion of tilapia farming had a few obstacles such as lack of availability in good quality of seed. Therefore sorting was needed to incrased the quality of seed. Sorting was put in the right order activity of certain size from largest into smallest then eliminated a little part of the smallest size however grading was only devided certain size into groups without elimination. The experiment was aimed to knew and saw the role of once sorting to the size variety of tilapia seed. The experiment was done toward of seed tilapia that get from cross breeding on various strain of tilapia that are : (A) case-1 : the black tilapia male broodstock of GESIT breed with the red tilapia female broodstock, (B) case-2 : the white tilapia male broodstock with the black tilapia female broodstock of Nirwana, (C) case-3 : the white tilapia male broodstock with the red tilapia female broodstock, (D) control : the black tilapia male broodstock of GESIT breed with the red tilapia female broodstock. The data that have got was analysed with MS. Excel 2007. Parameter that watched were average, standard deviation, variance of standard length and weight, survival rate and ratio of male and female. After done sorting in first month, the average of standard length increased as big as 1.28 % (case-1), 4.73 % (case-2), 1.93 % (case-3) and 3.42 % (cumulative). Meanwhile, the variation decreased as big as 15.19% and 28.08% on case-1, 21.52% and 38.41% on case-2, 7.75% and 14.41% on case-3, 13.88% and 25.84% on cumulative with this sorting. After rereared, in the second and third month the average and variation value increased on entire cases and cumulative. However on control the value of length standard average was not increased and the variation was not decreased on the first month. | en |
