Comparative Study of Tilapia Nilotica (Oreochromis Niloticus) In the Aspect of Quality of the Harvest and Hatching between River Base Cage Culture and Earthen Pond

Abstract

The reason for choosing the titled work that in Bangladesh work on hatching & rearing the offspring keeping on Cages in river has not yet been developed. And comparing it to the traditional hatching and nursing system for tilapia fish fry is still not discovered. The entire experiment has done under the breeding season of tilapia (March to August). And Brood stocking, feeding, Egg collection has done at the same time at same rate so that we find the exact outcome of the study. The location of the study chose carefully cause we need an earthen pond based tilapia hatchery and a river beside it so that we can run the study at a time simultaneously. Considering this fact Muhuri project area is the best. The difference that we observe between two different sampling place (Cage and Pond) on the result is its egg collection rate, egg size, hatch survivability and hatch deformity. All those aspect samples from the cage shows better result most of the time than that of samples from the earthen pond. Egg collection starting first from the broods from 12 May 2011 both in pond and cages and at a regular interval collection process kept up to 4 June 2011 in 3 different phases. Highest size of the egg sample found .2mm from the river cages and lowest size found .1mm both from pond and cages. Similarly egg collect rate per brood is highest observe 20gm/4 pieces of mother from the river reared broods and lowest collection rate found 15gm/10 pieces of broods. And hatch survivability rate of eggs observed highest is 100% at 17 May 2011 in spawning trey of river’s sampled eggs and lowest is 93% (1557 eggs survived from initial 1667 eggs) shown in the pond’s egg sample trey at 13 May 2011. At after hatching deformity of the juveniles has been counted for extended study. In that cage highest deformity of the offspring has been observed about 36count from the river reared sample. But total deformity counted less from pond sampled fry.