碩士 / 國立臺灣海洋大學 / 環境生物與漁業科學學系 / 99 / The study analyze the relations between age and growth of young swordfish (Xiphias gladius) in the Indian Ocean by using otoliths and samples are divided into the eastern and the western Indian Ocean based on fishing areas defined by the Indian Ocean Tuna Commission (IOTC).
A total of 36 (23 are males and 10 are females, and 3 are sex unknown) and 125 (58 are males and 49 are females, and 18 are sex unknown) specimens collected from the eastern and the western Indian Ocean respectively are used in present study. The lower jaw fork lengths (LJFL) of specimens range between 66 to 104 cm and 43-110 cm for the eastern and the western Indian Ocean, respectively. The results of likelihood ratio test indicate that the relationships between body weight and the lower jaw fork length are not significantly different between sexes. Therefore, sex-pooled data are used to estimate the relationship between body weight and the lower jaw fork length and the relationships are W = 2 × 10-6LJFL3.2314 and W = 1 × 10-6LJFL3.3743 for the eastern and the western Indian Ocean, respectively.
The method of index average percentage of error (IAPE) is used to evaluate the accuracy of aging determination. The values of IAPE range between 0.25-7.75% with average of 3.03% for the eastern Indian Ocean and range between of 0-8.25% with average of 2.41%. The results indicate that the accuracy of aging error should be acceptable.
Based on the otolith daily rings determined in this study, the linear and power regression are used to analyze the relationships between age and the lower jaw fork length. Since the body length of hatching should be close to zero theoretically, this study considers that power function could reasonably represent the relationship between lower jaw fork length and age. The average daily growth rate is approximately at 0.8mm‧day-1 and 1.4mm‧day-1 for the eastern and the western Indian Ocean, respectively.
The spawning date inferred for swordfish in the eastern Indian Ocean mainly concentrated in November 2006 and January 2007, while the spawning date for the western Indian Ocean mainly concentrated in January 2007, March and 2007 May to August.
Stage of Young swordfish growth rate analysis (91 to 180 days, 181-270 days, 271-360 days, 361-450 days) growth rate estimated to be 0.7 mm‧day-1, 0.4 mm‧day-1, 0.8 mm‧day-1 and 0.2 mm‧day-1 for young swordfish in the eastern Indian Ocean, and 6mm‧day-1, 1.5 mm‧day-1, 2.2mm‧day-1, 0.3mm‧day-1 and 1.4 mm‧day-1 for young swordfish in the western Indian Ocean.
Based on the results of this study, there are significant differences revealed for growth rates and estimated body length for fishes with age of 1 year. Therefore, this study inferred that different growth patterns might exist for young swordfish in the eastern and in the western Indian Ocean.
| Identifer | oai:union.ndltd.org:TW/099NTOU5451039 |
| Date | January 2011 |
| Creators | Kuo-Ming Huang, 黃國明 |
| Contributors | Sheng-Ping Wang, Wei-Chuan Chiang, 王勝平, 江偉全 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 87 |
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