| 英文摘要 |
In order to avoid cannibalism between grouper (Epinephelus coioides) from larvae to fingerling stage, cages in indoor system are used by enhancing the amount of feed intake. In this method water must be changed often in order to maintain it with high quality characteristics, due to this process long time and hand labor is needed. This study was conducted to develop a collector for feces and feed residues to save time and labor during the process. This project includes the cooperation of Yuan-Nan Chu, professor of National Taiwan University, an expert in automatic processes who designed and evaluated the collector, and our laboratory were responsible for testing the facility and developing a standard operation procedure (SOP) for culturing fingerling. The first part was to design and modify the collector, in which the airlift principle was used to remove feces and feed residues to be filtered in a box. The relation between air volume and flow rate was determined in order to take a reference to extend the facility in the future. The second part consists in two investigations in order to understand the differences between water quality and fish condition, with or without using the collector for the semi-circulation system developed by our laboratory. First investigation lasted for 24 hours and fish were fed to satiation, B treatment (without using collector) showed the double ammonia concentration than A treatment (using collector), but this difference was no significant for the nitrite concentration between two treatments. The second investigation lasted for 48 hours and fish were fed with a fixed ratio, the results showed that the total number of bacteria, concentration of ammonia and solid suspended in water of treatment B were higher than the same parameters measured in treatment A. There were no diseases observed during the experiment and treatments. Based on the above results, we can conclude that the usage of the collector in a semi-intensive system not only can remove feces and residues effectively but also reduce the daily cleaning and labor routine saving 50% of the labor time. |
