The present study was carried out to gain addi t ional informat ion on rearing, feed and feeding as well as hematological aspects of sea bass (Dicentrarchus labrax) fingerl ings reared in pen enclosures. This study lasted for 224
days in Manzala lake (Port Said Governorate). The experimental fishes were subjected to five various feeding systems as follows:(1) 100% trash fish, (2) 75% trash fish plus 25% dry pelleted feed, (3) 50% trash fish plus 50% dry pelleted feed, (4) 25% trash fish plus 75% dry pelleted feed, and (5) 100% dry pelleted feed. Experimental periods were divided into two intervals 1-112 and 112-224 days. The results obtained could be summarized as follows: 1-The highest body weight gain after 1-112 days or 112-224 days and 1- 224 days was obtained by group fed 25% trash fish plus 75% dry pelleted feed. 2-The relative feed intake was increased in the first period and decreased in the second period as the water temperature decreased. 3-The best feed conversion ratio (1.18), feed conversion efficiency (84%) and the highest value of protein efficiency ratio (1.8) during the first rearing period were obtained where fish received 100% trash fish as compared to other experimental groups of fishes. 4- Neither trash fish nor dry pelleted feed had a significant effect on
chemical body composition. 5- Neither trash fish nor pelleted feed had significant effect on hematocrit
value, hemoglobin concentration, and mean corpuscular hemoglobin. 6- Total serum protein contents decreased significantly (P<0.05) as the percentage pelleted feed increased.