| 英文摘要 |
The production and CPUE of the Pacific saury fishery from Taiwanese fleets in 2008 was 139,000 mt and 21.5 mt/d/v, which are the highest records in the history of the Taiwanese saury fishery.? The increase of the saury production and CPUE from 2007 to 2008 was 52,000 mt and 4.4 mt/d/v, respectively.? The production of the top 4 saury harvesting countries in the world, including Japan, Taiwan and South Korea, increased in 2008, except for Russia.? The fishing areas of the Taiwanese fishing vessels from June to December, 2008 are described in this study.? The distribution of the fishing area in 2008 was similar to 2007, while the northeast, southeast and central parts of the fishing ground in 2008 were more abundant than in 2007.? In the generalised additive model (GAM), constructed in this study, with six spatial, temporal and environmental variables, the largest source of variation was contributed by the year, followed by the month, and the least one was the bathymetric depth.? The abundance index increased from 1998 to 2008, and the most abundant month was October, followed by September, and the least one was July.? In addition, the high abundance schools occurred in the surface areas of about 42~45 °N, less than 15 ℃ water temperature, and the bathymetric depth of 3000~5000 m, while the less abundant schools occurred in the areas of about 160 °E.? Annual average of the catches at age (month) in 1994~2008 indicated that the largest percentage of the age group in the catches was the 12 months old fish (36.8%), followed by the 14 months old fish (28.5%).? Comparisons of the saury population structures, re-constructed by virtual population analysis (VPA), between 1994~2007 average and 2008 indicated that the largest fishing mortality occurred at 20 months old in both periods, while the fishing mortality of 18 and 22 months old fish in 2008 was larger and smaller than that in 1994~2007 average, respectively. |
