Age, growth and seasonal distribution of narrow-barred Spanish mackerel (Scomberomorus commerson) in the water off Taiwan
| Autor: | Yun-Sin Lo, 羅允信 |
|---|---|
| Rok vydání: | 2018 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 106 Narrow-barred Spanish mackerel, Scomberomorus commerson, is a highly valued food fish in Taiwan and is widely distributed from South Africa to Southeast Asia, north to China and Japan and south to southeast Australia. According to the fishery statistics reports, the catch of S. commerson dramatically drop after 2003 and enhancing fishery research and management are imperative. Totally 324 otoliths were examined to validate the period of opaque zone formation, which was the basis for the studies of age, growth and age compositions of S. commerson landed in Taiwan. The generated von Bertalanffy growth equation had L∞ = 117.4 cm, K = -0.5 year-1, t0 = -1.04 years. The age classes of 0-3 years constitute more than 90% of the catch in 2016 and 2017. Otolith stable oxygen isotope, sea sanility and water temperature was also used in estimating the seasonal distribution of S. commerson catched near Penghu island. The results suggested that the juvenile S. commerson were likely to distribute near Taiwan Banks and western coasts of Taiwan in spring, followed by the movement to East China Sea or South China Sea from spring to summer and returned to Taiwan strait in autumn. Then the fish moved into South China Sea again in winter. The fish might return to Taiwan Banks in spring of following year. The seasonal distribution of the juvenile S. commerson was closely associated with the mean water temperature of 23-25℃, which might be influenced by the Kuroshio and China coastal current. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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