| Summary: | 碩士 === 國立臺灣海洋大學 === 水產養殖學系 === 98 === Babylonia areolata is a high market value species of snails, mainly distributed in tropical areas. It has the advantages of fast growing, good taste, and high market acceptance. Recently, as a result of over-fishing,
there has been a rare availability of the species in the market.
This study investigated the optimum growth conditions, the susceptibility of water quality factors, and the different density by sanded-culture and plastic basket-culture for raising B. areolata. The most cost-effective culture model using different plastic basket-culture model, which with different density and different feeding frequency was also conducted in this research. The results showed that the optimum temperature and salinity were 25 - 30°C and 25 – 30‰ respectively. The survival rate for the group cultured at 30°C and 35‰ was slightly lower than other groups. The best feed conversion rate was obtained in the group cultured at 15° and 30‰. For study on the changes in ambient temperature, the rapid increase of temperature to 35°C or rapid decrease to 15°C could lead to the occurrence of mortality of the snail. The rapid decrease of salinity to 17‰ could also lead to mortality of the animal. For the tolerance test of dissolved oxygen, mortality started to happen after 6 days from the beginning of the experiment. The LC50 of S2-, total ammonia and NO2--N (water quality factors) for the snail were 35.06, 99.55 and 467.72 ppm, respectively. The weight gain rate and FCR of 900 granule/m2 group was the highest among sanded-culture group, and the survival rate of each group was around 96-98%. For the plastic basket-culture group, the weight gain rate and FCR of 100 granule/basket group was the best, and the survival rate of each group was 100%. among. The best cost-effective culture model was confirmed for the group using density of 200 granule/basket with feeding frequency for 4 days, while the worst was for the group using density of 400 granule/basket with feeding frequency 2
days.
In conclusion, the optimal culture conditions for Babylonia areolata obtained were 25 - 30°C and 25 - 30‰.The best density for sanded-culture obtained was 900 granule/m2. For the plastic basket-culture, the cost-effective was 200/basket with feeding frequency 4 days. In addition, the rapid decline in salinity and changes in temperature caused by heavy rain during the farming process could result in high mortality of the snail and should be prevented. Otherwise, problems of proboscis edema and the separation of shell and meat of the snail may occur leading to mass
economic loss.
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