AN OBSERVATION ON INTERGENERIC HYBRIDIZATION BETWEEN Labeo calbasu ~ X Cirrhinus mirigala

Abstract

Performance of intergeneric hybrids obtained through hybridation between Labeo culbasu <jl and Cirrhinus mrigula cr was evaluated in terms of fertilization, mortality and hatching rates and larval survi vality in fish hatchery at Manikgonj. The fishes were bred by administering Pituitary Gland ( PG) extract and a total of three pairs of spawners in three separate trials. Observations were made on the growth performance of the hybrid. Ovulation period varied from 3 hrs. 50 mins to 4 hrs, 30 mins. The rates of fertilization varied between 95.3%-96.6%. The incubation period ranged from 12 hrs to 13 hrs with the hatching rates of 87.6% . 93.8% at water temperatures between 30.6° . 32.0° C. It took about 2 hrs from onset of hatching to complete hatching. Egg mortality varied from 8.6% . 40.6%. The larval survival rate (up to 4 days after hatching) ranged from 45.1 % ±50% at the temperature of29.8° -32.0° C. During a one year study period the hybrid attained a length of 45.6% ± 2.106 em and a weight of 506.445.1 ± 15.112g. Growth performance of hybrid in terms of weight was faster than mrigel but slower than calbasu.