碩士 / 國立臺灣海洋大學 / 海洋資源管理研究所 / 95 / Sharks own various life history characteristics. Therefore, a shark management based on vital parameters is more reasonable and realistic. In this study, the life history traits of 63 populations from 39 species were collected from literatures. The life history parameters included the ratio between size at birth and asymptotic length (Lb/L∞), the ratio between size at maturity and asymptotic length (Lm/L∞), maximum age (Tmax), age at maturity (Tm), growth rate (k) and the ratio between fecundity and reproduction cycle (f/Rc) were anlyzed with principal components analyses (PCA) and calculated factor coordinates. After that, our research divided 63 shark populations into 4 groups based on the results of cluster analysis. The relationships between population increase rates and life history parameters were described by multiple regression equations. The results showed the first group has slow growth rate (0.034 yr-1 <k<0.103 yr-1) and high longevity (26 yr <Tmax<81 yr) (e.g. Isurus oxyrinchus, Carcharhinus obscurus etc.),the second has fast growth rate (0.103<k<0.358) and low longevity (9<Tmax<26) (e.g. Mustelus manazo, M. californicus etc.) ,the third group has late sexual maturity and low longevity(e.g. Alopias pelagicus, Notorynchus cepedianus),Rhincodon typus is a shark species with largest fecundity, highest longevity and slower growth rate than other species. For that reason, Rhincodon typus belong to the forth group. The results of empirical equations and traditional demographic analysis approach are simulated. The sharks classified by life history characteristics and estimated those population increase rates by grouped-multiple regression equations. Our empirical equations which need few parameters can reduce the uncertainties from estimating of life history parameters and increase the accuracy of population increase rates. This approach provides an economic and effective way for shark management.
| Identifer | oai:union.ndltd.org:TW/095NTOU5277001 |
| Date | January 2007 |
| Creators | Chun-hui Chen, 陳純慧 |
| Contributors | Kwang-Ming Liu, 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 | 131 |
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