Growth and Survival of Abalone, Haliotis asinina Linnaeus 1758, Reared in Suspended Plastic Cages

Abstract

The effects of different stocking densities and initial size on the growth and survival rate of the tropical abalone, Haliotis asinina were investigated in suspended plastic cages. The size of the plastic cages used throughout this experiment was 30×40×30 cm. During the experiment, a pre-determined
amount of seaweed (Gracilaria verrucosa) was added to feed the animals once every 2-3 d. Water quality measurements were taken weekly and the mortality rate of abalone was observed in the morning. In the first experiment, four stocking densities (40, 60, 80, and 100 pieces/cage) with ten replicates were used. After six months, growth in terms of shell length and total weight of abalone at 60 pcs/cage were the highest with values of 35.5±2.8 mm, and 13.5±3.3 g, respectively. The survival rate (78.2%) at this stocking density was also the highest. The stocking density of 60 pcs/cage was chosen for the second experiment, where abalone of three initial size ranges (4-5, 7-8, and 10-11 mm) in shell length were investigated in the same manner as the first experiment. It was found that abalone with an initial size range of 10-11 mm showed the best survival rate (82%) compared with 4-5 mm (46.2%) and 7-8 mm (64.8%). Consequently, it is suggested that abalone with an initial size range of 10-11 mm in shell
length should be stocked at a density of 60 pcs/cage for the first six months of the grow-out period using the suspended plastic cages system.