博士 / 國立臺灣海洋大學 / 水產養殖學系 / 102 / This study aimed at investigating three conservation issues on Formosa landlocked salmon: (i) to propose “Formosa landlocked salmon as an independent species” and what the phylogenetic relationship between Formosa landlocked salmon and three subspecies of Masu salmon complex (Oncorhynchus masou complex) (ii) what the genetic diversity and genetic structure of Formosa landlocked salmon, and who caused the gene pool homogenization (iii) to develop the LAMP and multiplex PCR method for sex and species identification of Formosa landlocked salmon.
The phylogenetic trees were reconstructed based on AFLP and complete mitochondrial genome sequences by using Bayesian inference method. However, the topologies of these two trees were different. Using AFLP data, Formosa landlocked salmon is the most distantly species related to others；On the contrary, Biwa salmon is the most distantly species related to others by using complete mitochondrial genome sequences. After due consideration of AFLP, mtDNA and geological history, it is suggested Biwa salmon first diverged from the common ancestor of Oncorhynchus masou complex. However, Biwa salmon and Amago salmon may have gene flow in the evolutionary history. These results show that instead of dividing from Msau salmon, Formosa landlocked salmon is the independently clade divided from the common ancestor of Oncorhynchus masou complex. Formosa landlocked salmon is considered as an evolutionarily significant unit (ESU) and even an independently species due to geographic separation and genetic differentiation among Masu salmon complex.
Genetic diversity of Formosa landlocked salmon in Chichiawan Stream are examined by using AFLP, Microsatellite, and mtDNA ND5 gene sequences. All of these data show the low genetic diversity in Formosa landlocked salmon. Genetic drift of wild Formosa landlocked salmon was detected and genetic diversity was subsequently lost from 2004 to 2008. There are two distinct clusters were found in Formosa landlocked salmon between Dams 1 and 3 in the year 2004 and 2005. One cluster show higher genetic diversity and the other show complete genetic homogenization. After comparison of samples from hatchery and wild population above Dam 3 in the year 2006, I hypothesize that gene pool homogenization were cause by large-scale cultivated fishes escape when Typhoon Ariel breached the hatchery in the fall of 2004.
In this study, simple, reliable, non-invasive LAMP and multiplex PCR methods were developed to identify sex and species of Formosa landlocked salmon. The reliability of sex and species identification is high (more than 98.40%) for Formosa landlocked salmon. The sex ratios (male/female) of field Formosa landlocked salmon from 2004 to 2008 were 0.59, 0.50, 1.19, 0.57 and 0.72, respectively. The sex ratio of 2007 was significant differed from 1:1 (p<0.05). The results indicate the sex ratio of Formosa landlocked salmon is not consistent with 1:1. Biased sex ratio has to be considered when effective population size is counted.
In summary, Formosa landlocked salmon is an ESU of Masu salmon complex and should be conserved. In conservation program, AFLP and sex marker are useful tools for genetic management and conserving maximum genetic diversity.
| Identifer | oai:union.ndltd.org:TW/102NTOU5086047 |
| Date | January 2014 |
| Creators | Hsu, Te-Hua, 徐德華 |
| Contributors | Gwo, Jin-Chywan, 郭金泉 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 123 |
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