碩士 / 臺灣大學 / 漁業科學研究所 / 98 / Paddlefish, one of the largest freshwater fish, are endemic to most river and tributaries of Mississippi basin and are found in 22 states in United States. Paddlefish, like sturgeon, are highly valued for its grayish-black roe that is processed into caviar and for their boneless, firm, white meat. Paddlefish have many outstanding characteristics as a food fish. Paddlefish filter feed primarily on zooplankton throughout most of their life and grow rapidly, also have high survival rate .Aquaculture of paddlefish is attracting increasing attention as an aquaculture species. A study is conducted examining the culture biology of paddlefish.
The first experiment was conducted examining the influence of water depths for feeding regimen of paddlefish. Twenty paddlefish juveniles of mean weight 15g were randomly stocked into cement ponds with flow in order to test the restriction for feeding paddlefish pellets from the bottom and the effect of water depth on floating pellets were fed. Results show that paddlefish cannot consume pellets from the bottom, and paddlefish can only be fed when the water depth is deeper than 40 cm.
The second experiment was conducted examining growth and feeding regimen of paddlefish as different times of pellets was fed a day. Twenty paddlefish juveniles of mean weight 5g were randomly stocked into cement ponds with flow. Paddlefish were fed one hundred pellets a day, but they were fed in twice, four times, six times, eight times a day, respectively. After measuring remnant of pellets, the result shows that paddlefish is fed six times and eight times a day the most adequately and there are less pellets left.
The third experiment conducted examining the effect of different irradiances on feeding regimen of paddlefish. Twenty paddlefish juveniles of mean weight 5g were randomly stocked into cement ponds with flow under the irradiances of 500lux, 1000lux, 2000lux, and 4000lux respectively. The result shows that paddlefish can maintain normal feeding regimen under the irradiances of 500lux and 1000lux but not the irradiances of 2000lux and 4000lux.
The fourth experiment conducted examining the effect of different salinity on survival of paddlefish. There was two phases in this experiment. Phase I: twenty paddlefish juveniles of mean weight 5g were randomly stocked into FRP tanks and 5ppt, 10ppt, 15ppt and 20ppt of salinity respectively. The activity of paddlefish was recorded within following 96 hours. Phase II: three different ways to increase the salinity was implemented in reservoirs. One was to increase 1ppt of salinity daily until the salinity of water reaching to 10ppt. Another was to increase 4ppt on first day, and wait for three days, and then increase 3ppt every three days until the salinity of water was 10ppt. The other was to increase 5ppt every five days until the salinity of water was 10ppt. The result shows that paddlefish in 10ppt, 15ppt, and 20ppt tanks will present following reaction accordingly: 1. Paddlefish would swim around the reservoirs, FRP tanks, slowly. 2. Paddlefish would swim fast, or even strike themselves against the tanks. 3. Paddlefish would move slowly down to the tanks and lose their balance. 4. Paddle would stop moving and die in the end. However, in the tank of 5ppt of salinity, there were no abnormal activities shown for paddlefish. The result also shows that the best way of raising salinity in water is to increase 1ppt of salinity daily, and the other ways will cause the death of paddlefish.
The fifth experiment conducted examining the effect on growth, survival, and fillet composition of paddlefish when fed commercial feeds differing in protein and lipid level. Thirty paddlefish juveniles of mean weight 20g were randomly stocked into cement ponds with flow, and were fed floating commercial eel feeds (45% protein, 11% lipid, the highest protein), commercial floating tilapia feeds (28% protein, 6% lipid, the medium protein), and commercial floating milk fish feeds (24% protein, 6% lipid, the lowest protein) respectively. The paddlefish were harvested after 120 days. At harvests, it shows there are no differences in relative growth, specific growth rate, feed conversion rate, percent survival, and fillet composition of paddlefish between the medium protein and the lowest protein treatments. Yet, the ratio is significant higher for paddlefish fed the eel feed (the highest protein treatment) compared with the others. Paddlefish fed the eel feed contain much EPA and DHA because of higher EPA and DHA of eel feed.
| Identifer | oai:union.ndltd.org:TW/098NTU05451003 |
| Date | January 2010 |
| Creators | Kai-Hsian Chan, 詹凱翔 |
| Contributors | 廖文亮 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 60 |
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