碩士 / 國立臺灣海洋大學 / 海洋事務與資源管理研究所 / 107 / Stock structure of Croaker (Johnius distinctus) in surrounding waters of Taiwan were examined based on the otolith morphometry (OM) (including morphometric indices (MI) and elliptical Fourier analysis (EFA)), truss network analyses (TNA) and the life history characteristics (LHC) of the species. Samples for the OM and TNA were collected from fishing ports of the New Taipei City (NTC), Miaoli (ML), Penghu (PH) and Changhua (CH) on October 2018, while those used for the comparisons of LHC were collected previously from NTC between April 2011 and October 2014, and CH between March 2017 and March 2018. Significant differences were found among sites from both combined and separated EFA and MI analyses (MANOVA, p < 0.05). However, site to site comparisons from MI analyses indicated significant differences between sites except for that of CH and ML, but no differences were found from EFA among three sites CH, ML and PH, and between NTC and CH (MANOVA, p>0.05). For the combined analyses, significant differences were found (MANOVA, p < 0.05) among sites except for that between CH and ML. The classification success by the discriminant analysis among 4 sites were between 66.9 and 93.8%. For the TNA, multivariate analyses based on 14 parameters screened for normality and homogeneity of variance showed significant differences among sites, and between each sites (MANOVA, p < 0.05). Results from factor analyses indicated that the first 2 factors explained 77.3% of the variances. Variables represented for the caudal peduncle gave high loadings on the first factor, and those from upper edge and posterior half of the fish body showed meaning loadings on the second factor. The score plots for the first two discriminant functions also showed a separation between four sites although some overlapping were also noticed. The overall classification success were between 77.8 and 92.7%. Significant differences in length-weight relationships between sexes and sites of NTC and CH were also found. Energy reserves represented by the hepatosomatic index (HSI), visceral index (VI), condition factor with and without visceral (CF1 & CF2) and gonadosomatic index (GSI) by maturity stages also showed significant difference between sites for most of the indices. Two major spawning seasons (Apr.-July and Aug.-Oct.) for samples collected in CH was evident while it was only one season (May-Sept.) for NTC. The size at 50% maturity was 14.8 cm for female and 12.8 cm for male in CH, which were apparently smaller than those in NTC (21.8 cm for female and 18.6 cm for male). In judge of these evidences, multiple stock structure of J. distinctus including PH, NTC and ML-CH in surrounding waters of Taiwan was suggested, although the ML-CH stock may still need to be further verified.
| Identifer | oai:union.ndltd.org:TW/107NTOU5277003 |
| Date | January 2019 |
| Creators | Wang, Wei-Ju, 王唯儒 |
| Contributors | Wang, Shyh-Bin, 王世斌 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 66 |
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