Stock assessment of sailfish(Istiophorus platypterus) in the Indian Ocean using data-limited methods

• Main Authors: Chen, Hung, 陳鋐
• Other Authors: Wang, Sheng-Ping
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/26144160796377936832

碩士 === 國立臺灣海洋大學 === 環境生物與漁業科學學系 === 104 === Sailfish (Istiophorus platypterus) is a highly migratory fish that inhabits tropical and subtropical Atlantic, Pacific and Indian Oceans. In the Indian Ocean, sailfish is mainly caught by gillnet and longline fleets of the countries around the Arabian Sea. Catches increased sharply since the 1990s and the average catch exceeded 29,000 tones in recent years. Due to lack of biological information and effort for sailfish in the Indian Ocean, this study adopts Catch-MSY method and Depletion-Based Stock Reduction Analysis, which need only history catch and prior distribution of life history parameters and stock parameters, to conduct the assessment for sailfish in the Indian Ocean. The results of both methods indicate that catches and fishing mortality substantially increased and biomass decreased gradually since the 1990s. Currently, the stock status is not overfished. However, fishing mortality obtained from Catch-MSY method is at a high level, while, fishing mortality obtained from DB-SRA is still below FMSY. Comparing to Catch-MSY method, the estimates of DB-SRA are more robust and DB-SRA can incorporate more biological and stock parameters. However, the results of this study indicate that the model estimations of DB-SRA are influenced by the assumption of depletion. To further understand the population dynamics of sailfish in the Indian Ocean, improvements in data collection and quality of fishery statistics and are necessary. In addition, biological studies of sailfish in the Indian Ocean should be enhanced simultaneously.