碩士 / 國立臺灣海洋大學 / 環境生物與漁業科學學系 / 104 / The whitespotted bamboo shark, Chiloscyllium plagiosum, is the dominant species of small sharks caught in the northern waters off Taiwan and it plays an important role in the marine ecosystem in this region. This study aims to estimate the trophic position and ecological niche of the whitespotted bamboo shark using stable isotope analysis. The white muscle under the first dorsal fin was taken from the 78 specimens (32 females, 46 males) collected at the Fugi fishing port, in New Taipei City from October 2013 to March 2015. These samples were used for stable isotope (δ13C, δ15N) analysis. Female specimens ranged from 41.0 to 84.0 cm TL with a mean ± SD of 64.3 ± 13.5 cm, whereas body weight ranged from 180 - 2500 g (925.8 ± 579.6 g). Male specimens ranged from 39.0 to 84.0 cm TL (mean = 59.4 ± 13.5 cm), while body weight ranged from 205 to 2000 g (mean = 755.0 ± 506.2 g). Stable isotope analyses indicated that δ13C ranged from -17.05 to -14.76‰ with a mean of 5.75‰ ± 0.51‰, and δ15N ranged from 10.83 to 13.29‰ with a mean of 12.46‰ ± 0.69‰, for females. The estimated δ13C ranged from -16.90 to -14.62‰ (mean = -15.83‰ ± 0.44‰), and δ15N ranged from 10.95 to 14.37‰ (mean = 12.36‰ ± 0.74‰) for males. No significant difference was found between sexes for the mean values of δ13C and δ15N with t-test (δ13C: df=76, p=0.437; δ15N: df=76, p=0.559). Significant difference was found between different maturity stage on the mean values of δ13C and δ15N with t-test (δ13C:df=76, p<0.05; δ15N: df=76, p<0.05). The analysis of variance indicated that there is significant difference among seasons on the mean value of δ15N and multiple comparison results indicated that of the second season was lower than those of other seasons. The mean values of δ13C and δ15N increased with the length of the fish. Mean trophic position of whitespotted bamboo sharks for both sexes is 4.19, and are 4.06 and 4.39 for the immature and mature, respectively. It is found that whitespotted bamboo sharks have an ontogenetic shift of diet when they reach mature.
| Identifer | oai:union.ndltd.org:TW/104NTOU5451022 |
| Date | January 2016 |
| Creators | Chang, Sheng-Kai, 張勝凱 |
| Contributors | Joung, Shoou-Jeng, Liu, Kwang-Ming, 莊守正, 劉光明 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 52 |
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