P.O. Ajah-1997
The Israeli Journal of Aquaculture - Bamidgeh, 49(4) : 205-213
Abstract:
In both laboratory and outdoor culture environments, Heterobranchus longifilis larvae fed a combination (Diet 1) of mixed live zooplankton and artificial diet grew significantly longer (p<0.01) than those fed mixed live zooplankton (Diet 2) or an artificial diet (Diet 3; 0.5 mm particle size) alone. Those fed the zooplankton grew significantly longer (p<0.01) than the larvae fed the artificial diet. Larvae fed Artemia nauplii (Diet 4) were significantly longer (p<0.01) than the larvae fed Diets 1, 2 and 3 on both the 6th and 11th days of culture. The overall best biomass (8.3 g) was obtained by larvae fed Diet 1 followed by Diets 2 (4.9 g), 3 (2.1 g) and lastly 4 (2.0 g). At day 11, the best individual growth (3.4 cm, standard length; 0.47 g wet weight) was recorded among larvae fed Diet 4, followed by 2.1 cm and 0.13 g for Diet 1, 1.5 cm and 0.06 g for Diet 2 and 1.3 cm and 0.04 g for Diet 3. Specific growth rates were 4.8%, 34.8%, 28.3% and 23.1% for larvae fed Diets 4, 1, 2 and 3, respectively. The decrease in survival from day 6 to 11 was 98% to 79%; 76% to 65%; 73% to 61% and 28.25% to 4.25%, for diets 2, 1, 3 and 4, respectively. In the outdoor culture, larvae fed Diet 1 grew significantly longer and had a higher SGR than those fed Diets 2 or 3.
(Institute of Oceanography, University of Calabar, Calabar, Nigeria)