Studies on the Establishment of Seawater Fish’s Egg Hatching and Larval Rearing System

• Main Authors: Ming-Feng Lee, 李明鋒
• Other Authors: Jiunn-Ming Chen
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/81965179260635411921

碩士 === 國立中興大學 === 生物產業機電工作學系 === 91 === In this research, an indoor seawater-recirculating system for the fish’s egg hatching and early larvae development was designed and established. By controlling and managing the quality of water, to maintain it at a suitable culture environment, this system could diminish bacteria and viruses to improve the egg hatching rate and the fry survival rate. The fundamental test was conducted using Lateolabrax japonicus egg. The effects of three ways of water sterilization, the non-sterilization, sterilization with ozone and sterilization with ultraviolet, on the egg hatching rate and the fry survival rate were investigated. The testing results showed that the hatching rates had no significant difference (p＞0.05) under these three sterilization conditions and all reached up to 85﹪. However, only the non-sterilization and the sterilization with ultraviolet cases had no significant difference(p＞0.05) on the fry survival rates which were 64.05±1.72﹪and 69.87±3.40﹪,respectively.Both had a significant difference (p＜0.05) with the value of 53.37±3.47﹪obtained using sterilization with ozone. The egg hatching rates and the fry survival rates of Lateolabrax japonicus egg tested in different salinity seawater were used to explore the appropriate range of salinity. The experimental results showed that the salinity of 28 ppt was the most preferable environment for fish’s egg hatching and 23 ppt was the best condition for the early larvae survival in the beginning period. The suitable salinity range for Lateolabrax japonicus egg hatching and larvae rearing was between 23 and 32 ppt. As regard to the development of Lateolabrax japonicus larvae in the cultivating tank, the fry survival rate of non-sterilization environment was the highest of all. The fry survival rate of ultraviolet sterilization was higher than ozone sterilization because during the process of ozone sterilization, the byproducts were produced and would harm to the fish larvae. Therefore, in purpose of larvae rearing, ozone sterilization used in this system was still not appropriate. The system established in this research also indicated a fine result of water treatment. The fish’s egg hatching and fry survival could attain higher rates than the traditional operation process. However, in the post period of larvae rearing, the improper feeding caused the malnutrition and death of larvae. Thus, the future work may focus on the nutrition control of fish larvae in the post period.