碩士 / 國立中山大學 / 海洋事務研究所 / 104 / Spotwing flyingfish (Cypselurus poecilopterus) is one of the dominant species in the Kuroshio off Taiwan, and it occupies a high proportion in the catch of flyingfish. In recent years, the catch of flyingfish has declined substantially, and for some years the fishing season was postponed or pulled forward, but whether the population structure has been damaged by human fishing is still unknown. Therefore, the aim of this study is to investigate the growth and reproduction of C. poecilopterus in the Kuroshio off Taiwan and provide scientific information for its fishery management. Specimens of C. poecilopterus were collected monthly through setnet, drive-in net, and gillnet fisheries from April 2010 to March 2012, mainly gathered from Ilan, HuaLien, TaiTung, PingTung and Lyudao.
In order to understand the most suitable growth equation of C. poecilopterus, the asteriscus otolith was used to estimate the ages. Its daily growth increment (DGI) was then fitted to von Bertalanffy (VBGE), Two-phase, and Logistic growth equation for estimating the parameters through nonlinear regression. The DGIs of annual total and summer specimens were used separately to fit with those growth equations. Results show that the equation of VBGE of summer specimens is the most suitable one for C. poecilopterus. The asymptotic length and the growth coefficient for this equation are 22.73 cm and 0.011 cm d-1, respectively.
According to the histological examination of ovaries, gonadosomtic index, and the hatch date estimated from VBGE of fork length, the reproductive period of C. poecilopterus occurs during April to July and November to January. From the histological examination of ovaries and oocyte diameters, C. poecilopterus is believed to be a group-synchronous species.
This study argues that C. poecilopterus is a fast-growing species with a short longevity. Therefore, under proper management and decreasing the fishing pressure, its biomass should be able to recover rapidly. However, because of the narrow-size range in the catch, a restriction of size is infeasible for management. A limitation of the amount of catching or a prohibition of fishing areas is considered to be a better alternative.
| Identifer | oai:union.ndltd.org:TW/104NSYS5274003 |
| Date | January 2016 |
| Creators | Chia-ho Tsai, 蔡嘉和 |
| Contributors | Shui-Kai Chang, 張水鍇 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 72 |
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