碩士 / 國立臺灣海洋大學 / 水產養殖學系 / 92 / Abstract
Needle-tooth moray, U. macrocephalus and tidepool snake moray, U. micropterus of genus Uropterygius have been collected and recorded in Taiwan. This study studies the Uropterygius species and records the amount of individual species found in the waters around Taiwan from 2001 to 2003. We collected a total number of 115 individuals of U. macrocephalus from Taitung Chengkung. U. macrocephalus are only to be found in Chengkung along an area near the coastline abundant with lava boulders. U. macrocephalus seem to enjoy feeding in areas exposed to the wave action nearby the waterline. We also found 225 individuals of U. micropterus in Hsiaoliuchiu, Kenting, Jioupeng, Gihaw, Chengkung, Lutao, and Lanyu. U. micropterus are very common in the coral reef waters of Taiwan. These U. micropterus always rest in the intertidal regions where there is sand and gravel as substrate and they have strong tolerance for water turbidity. Howerve, U. micropterus do not have a single, stable habitat; they tend change habitat according to where food is most available and abundant. We found that Echidna nebulosa where U. micropterus is also found. Both of these two Uropterygius species have similar feeding behaviors: home, search, strike, orient, “M,” rotate, knot, shake, release, probe, and feed.
We collected various biological data and information from specimens captured. For years 2001 and 2003, the most frequent occurring length of captured U. macrocephalus is between 20~25 cm, and we are able to calculate a length-weight relationship formula for this species. We also collected the biggest U. micropterus recorded to-date form Lutao. Using the specimens collected in the three years, we calculate weight and length relationship formulas for them. The average total length of matured female U. macrocephalus is 23.44±2.84 cm with GSI 4.51±4.32, egg diameter 0.91±0.22 mm and fecundity 1591.60±930.21. The average total length of matured male U. macrocephalus is 12.87±1.08 cm with GSI 5.41±1.51. For both male and female, the right gonad is bigger than the left gonad. The sex characteristics of the male and female are: the head of the male is blunter compared to female, and that the number of prevomer, upper jaw, and lower jaw maxillary teeth are different. Most specimens of U. macrocephalus are of the gonochoristic type; however, we found in a particular specimen with oogonical-like cells in testis tissue, suggesting the possibility of sex reversal. The average total length of female U. micropterus is 22.37±4.41 cm with GSI 6.09±4.21, egg diameter 1.13±0.16 mm and fecundity 768.92±547.90. The average total length of male U. micropterus is 23.32±4.64 cm with GSI 12.47±4.93. We found the same sex characteristics as found above for U. macrocephalus species: both female and male gonads are bigger on the right, head of the male is more blunt compared to the female, and the number of prevomer, upper jaw, and lower jaw maxillary teeth are different. But another sex characteristic was frequently found, there is a dark spot around the anus of female U. micropterus. Furthermore, growth studies were carried out on U. micropterus in lab. After 60 days of rearing, those with body lengths of 0~15 cm their growth rate is 20.42±4.15 ％ and FCR is 4.92±1.25 compared to those from 15~30 cm their growth rate is 3.65±5.36 ％ and FCR is 7.44±8.19. After 90 days of rearing, in different seasons, the summer growth rate is much faster than the winter growth rate. After 1 year of rearing, U. micropterus with body length of 0~15 cm has a faster growth rate (73.65) than those with body length of 15~30 cm (15.68±0.01).
| Identifer | oai:union.ndltd.org:TW/092NTOU5086001 |
| Date | January 2004 |
| Creators | Shih-Ying Tien, 田詩縈 |
| Contributors | Hong-Ming Chen, 陳鴻鳴 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 94 |
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