EFFECTS OF SIZE-SELECTION ON GROWTH AND B ODY CONSTITUENTS IN RED-SEABREAM JUVENILES

In order to examine the effects of size-selection on growth and body c onstituents of red sea bream juvenile, two experiments were carried ou t using Lot 1 (76 days, 36.1 +/- 4.6 mm) and Lot 2 (65 days, 29.9 +/- 5.4 mm). In experiment I, the small size group (S-1; 31.8 +/- 2.0 mm, n = 70) were selected from Lot 1. As a control, a medium size group (M -2; 31.7 +/- 1.9 mm, n - 70) were selected from Lot 2. Rearing was con ducted for 48 days, mixing the S-1 group with the M-2 group. In experi ment II, the large size group (L-2; 37.4 +/- 1.6 mm, n = 70) and mediu m size group (M-1; 38.1 +/- 1.8 mm, n = 70), selected from Lot 2 and L ot 1, respectively, were also compared. No differences of size distrib ution and daily growth rate after 48 days rearing were observed betwee n the S-1 and M-2 groups. The growth and size distribution of the L-2 and M-1 groups also showed no marked difference. The size-selection en hanced not only the RNA/DNA ratio but also lipid and triglyceride accu mulation in the small size group. These results indicate the usefulnes s of the size-selection and suggest that runty fish can grow as well a s medium size fish.