| 英文摘要 |
The production of the Pacific saury fishery from Taiwanese fleets in 2009 was high, 104,000 mt, which is the third highest harvest recorded in the history of the Taiwanese saury fishery, 35,000 mt less than the highest harvest of 2008.? The number of fishing vessels in the 2009 Taiwanese fleets was 72, which is the highest number of vessels in the Taiwanese saury fishery history, 4 more than in 2008.? The CPUE in 2009 was 13.7 mt/day/vessel, which is 7.8 mt/day/vessel less than in 2008.? Decrease in percentages of production from 2009 to 2008 were smallest in Japan (-10.2 %), largest in Russia (-62.3 %), and medium in Taiwan and South Korea (-25.3 and 25.7 %, respectively) for the top 4 saury harvesting countries in the world.? The abundance distribution of the fishing area in 2009 was different from 2008. ?There was a high CPUE area in the southwest part of the fishing grounds in 2009 but not in 2008.? Correlation coefficients of the suitability indices to the 8 marine environmental variables, not including net primary productivity, were significant.? These coefficients ranged from 0.093 to 0.211.? Range of the habitat suitability index (HSI) estimated in 2007 was from 0 to 0.78.? Prediction rate of the grids of the HSI ＞ 0.6 to the CPUE ＞ 13.8 mt/day/vessel for 2007 was 23.3 %.? Range of the HSI in 2008, lacking sea surface temperature data, was from 0 to 0.64.? Prediction rate of the grids of the HSI ＞ 0.6 to the CPUE ＞ 13.8 mt/day/vessel for 2008 was 0 %.? ?Over 2004-2009, the largest and smallest percentages of 1+ year-old saury, the main spawning group, in the catch occurred in 2005, 66.8 %, and 2009, 29.1 %, respectively.? The age structure in the catch of 2009 was younger compared with the historical data.? The catches at age (month) in 2009 indicated that the largest percentage of the age group in the catches was the 10 months old fish (43.9 %), followed by the 8 months old fish (19.2 %).? The population structures of saury, re-constructed by virtual population analysis (VPA), in 2009 indicated that the largest fishing mortality occurred at 14 months old, followed by the 16 months old fish. |
