A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science, School of Environment, Resources and Development

Thesis (M.Sc.) - Asian Institute of Technology, 2006

The tropical abalone Haliotis asinina, also called donkey-ear abalone, is a highly valued marine mollusk with very high export potential but its culture techniques still need to be developed. An experiment was conducted to investigate the effects of stocking density and shelter surface area on the growth and survival of abalone reared in fiberglass tank (0.50 m2 in bottom area) with a semi-flow through system (water volume = 0.2 m3). Abalone with average initial body weight of 1.42 g and shell length 18.7 mm were stocked at stocking densities of 100, 200 and 300 abalone m 2. One, two or three pieces of Vshaped PVC shelters were added to the tanks during the culture period. Abalone were provided with artificial diet (25% crude protein) at a feeding rate of 2.0-2.5% of body weight daily for 201 days (6.7 months). In the first 5 months of culture, there was no significant difference (P>0.05) in specific growth rates (SGR) in body weight, shell length, shell width among treatments. At the end of culture period (March), there was no significant difference in specific growth rates among three shelter surface areas (0.09, 0.18 and 0.27 m2) at stocking densities of 100 and 200 pcs. m-2, but at 300 pcs. m 2 with three shelters (0.27 m2) abalone had significantly higher (P<0.05) specific growth rates for body weight and shell length. Also at 300 pcs. M-2 with two shelters (0.18 m-), abalone had significantly higher specific growth rate for shell length at the end of culture period. There was no significant difference in specific growth rate for shell width at different stocking densities and shelter surface areas throughout the culture period. These results indicate that at higher stocking density of 300 pcs. m 2, at least 3 shelters (0.27 m2) are needed on the sixth month, since growth decreases with increasing density but increases with increasing shelter surface area. In this experiment, abalone survival was not affected by stocking density and shelter surface area. This may be explained that even if abalone cannot feed enough as a result of stacking due to lack of shelter surface area, they can still survive but not grow well