碩士 / 國立臺灣海洋大學 / 環境生物與漁業科學學系 / 107 / Both two species of fourfinger threadfin (Eleutheronema tetradactylum and E. rhadinum) are commercially important fishery resources in coastal waters off western Taiwan. However, they are rarely separated in the catches of coastal gillnet and set-net fisheries, preventing the understanding of their population dynamics. Fish samples of the two species were collected from the Tamsui, Miaoli, Yunlin, and Kaohsiung fishing ports in this study. External morphometric characteristics (the color of pectoral fins, lateral line squamation on the caudal-fin membrane and different scale counts of pored lateral line and those above and below the lateral line) and microchemistry of otolith core (trace elements including Sr/Ca, Ba/Ca, Mg/Ca, Fe/Ca and Pb/Ca ratios) were used to identify the two species of E. tetradactylum and E. rhadinum.
Yellow pectoral membranes were found for E. tetradactylum, with branch lateral line on caudal fin base, scale counts of pored lateral line from 65 to 79, and scale rows above and below lateral line ranging between 8-12 and 11-16, respectively, while black pectoral membranes and un-branch lateral line on caudal fin base were identified for E. rhadinum, with scale counts of pored lateral line from 80 to 98 and scale rows above and below lateral line ranging between 9-14 and 10-18, respectively. The relationships between fork length and body weight, fork length and otolith radius, and body weight and otolith weigh were insignificant among sampling locations for E. rhadinum based on likelihood ratio tests. All the trace element ratios of otolith core were statistically insignificant among sampling sites, but otolith weight to body weight and the condition factor of reared E. tetradactylum were statistically higher than those for wild individuals.
The trace element ratios of otolith core were found insignificant among sampling sites, but statistically differed between the released reared samples (Ba/Ca: 18.83±1.66 mmol/mol) and wild individuals (4.78±1.04 mmol/mol). In addition of trace element ratios, condition factors, otolith radius ratios and otolith weight to body weight were demonstrated to separate wild and released reared fish successfully. Results derived from this study suggest that external morphometric characteristics and trace element ratios of otolith core were considered useful tools to identify the two species of fourfinger threadfins.
| Identifer | oai:union.ndltd.org:TW/107NTOU5451029 |
| Date | January 2019 |
| Creators | Huang, Li-Chun, 黃莉鈞 |
| Contributors | Su, Nan-Jay, Wang, Chia-Hui, 蘇楠傑, 王佳惠 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 75 |
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