碩士 / 國立臺灣海洋大學 / 海洋事務與資源管理研究所 / 97 / Fisheries biology of Pagrus major in waters off northern coast of Taiwan was examined based on samples collected between Oct. 2007 and Dec. 2008. In total, 380 fishes including 120 males, and 202 females, as well as 58 undifferentiated individuals were collected. Size of fishes ranged from 13.7 cm to 86.0 cm in length, and 37.5g to 8640.0g in weight were recorded. There was no difference found in body weight – total length relationships for both sexes. The combined equation is BW=0.02905TL2.79926. The formation of annuli for the species was found between April and June. The maximum ages for male and female fishes were estimated to be about 8 and 16, respectively. The von Bertalanffy growth equations in length (cm) and weight (g) estimated by non-liner method were Lt=125.4(1-exp(-0.0791 (t+0.3656))) (for ages 1 ~ 8) and Lt=110.5(1-exp(-0.0944 (t+0.2779))) (for ages 1 ~ 16), and Wt=21,718.33(1-exp(-0.0791 (t+0.3656)))^2.79926 (for ages 1 ~ 8), Wt=15,242.23 (1-exp(-0.0944(t+0.2779))^2.79926 (for ages 1 ~ 16). Males matured at age 4.8 and female at age 4.1. Spawning season of the species was between January and April. The size at first maturity for male fish was 42.0cm (TL), and was 37.0cm (TL) for female. Female fish was also more abundant than male, possibly related to the sex reversal reported for the species. The condition factor (CF) for both sexes start decrease after fall, and reached the lowest value in March-April period before it increase again on May. The hepatosomatic index (HSI) and visceral index (VI) of the species were the lowest on Mar. after peak spawning, and maintained at relative high after spawning. These results indicated that Pagrus major may use energy reserved mainly in the muscle, and partially in the liver and visceral for spawning. P. major feed mainly on Arthropoda, (i.e., crabs and shrimps) Echinodermata, (i.e., sea urchin) Molluscan (i.e., cuttlefish and Octopus) and Teleostean (i.e., fishes). The results of this study are also compared with reports from early years and from Japan to understand potential impacts of fishery, and influences of geographical differences.
| Identifer | oai:union.ndltd.org:TW/097NTOU5274007 |
| Date | January 2009 |
| Creators | Yin-Liang Liu, 劉胤良 |
| Contributors | Shyh-Bin Wang, 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 | 97 |
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