碩士 / 國立嘉義大學 / 水生生物科學系研究所 / 105 / Crown conch (Hemifusus tuba) is a valuable aquatic products in Taiwan. In recent years the number and size of wild crown conch deeply reduced and short of supply for the market. However, there are only a few studies on the breeding methods and feed crown conch. Consequently, this study was conducted "The effect of different sizes of female conches on the quality of their egg capsules, "The effect of different temperatures on the incubation of egg capsules ", "The effect of different live feeds on the growth of larvas ", and "The effect of different feeds on the growth of larvas ", which can provide a better breeding knowledge and artificial feed formula for this species, and provide some background knowledge for farming knowledge and artificial feed of crown conch in Taiwan.
The results of this study showed that, the size of the female conch from the waters of Dongshi, Chiayi on the number of egg capsules, the number of eggs within the capsule, the day of incubations required, the number of incubation per egg capsules and incubation rate are no correlation. But when the size of the female conch is larger, the egg capsules of the female conch are shorter. When the size of the egg capsule is smaller, the larvae are bigger. And the larger larvae type may increase its open bait selectivity and survival rate. So the hatchery workers should still choose a larger crown conch for breeding.
In the environment of salinity of 30 ‰, the larvae of crown conch were incubated at 20℃, 25℃ and 30℃, respectively. The results of the incubation of the egg capsules performed best at 25℃ group, not only the growth of embryos were best, the proportion of embryo agglomeration was low, the number of days required for hatching was shorter and the hatching rate was highter. The incubation of the egg capsules performed worst at 30℃.
Feeding the postlarvae of oyster with shells(postlarvae length : 18.23 ± 1.51mm, postlarvae weight : 54.80 ± 5.95mg), postlarvae of clam (postlarvae length : 11.22 ± 0.05mm, postlarvae weight : 2.49 ± 0.15mg) and the mixed both feed to the larvae of crown conch can be seen during 0 to 3 weeks should be fed with postlarvae of clam. Not only to improve the survival rate, there are more weight gain. However, after three weeks, the survival rate of the postlarvae of clam group was no longer higher than other groups. Growth was not as good as expected. Similar result was also found in other treatments. This indicated that, hatchery workers should try other fed other feeds that provide balanced nutrition after three weeks.
The results of the survival and growth of the larvae with the postlarvae of oyster with shells treatment, the postlarvae of clam treatment, the clam meat treatment, the artificial feed and the artificial feed supplemented with clam juice treatment were similar to the results of "The effect of different live feeds on the growth of larvas ".
The specific growth rate of the postlarvae of clam treatment was higher in the 2 to 4 weeks (7.41%·d-1), and the postlarvae of clam treatment was the only surviving group at the sixth week. However, the specific growth rate in the 4 to 6 weeks was negative (-8.75%·d-1). So feeding larva for four weeks after the incubation should be fed with the postlarvae of clam.
| Identifer | oai:union.ndltd.org:TW/105NCYU5061009 |
| Creators | 曾也慧 |
| Contributors | , 郭世榮, 董哲煌 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 0 |
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