| 英文摘要 |
In this study we aim to analyze the fishing condition and stock abundance of albacore tuna in the temperate Pacific Ocean in relation to climatic variability. Ecological and environment coupled models will be established in order to evaluate possible impact from climatic and environment variability. In order to investigate the possible influence of climatic change on albacore, we used catch and effort data from Taiwanese longline, and oceanic environmental data including SST, sub-layers temperature and?SSH?during 1981~2009 as major sources to conduct GLM and EOF analyses. We can conclude from the analyses as follows. The time serial albacore abundance (total catches) seemed to track of 1st component of EOF from water temperature with time lags of 2~5 years. There were also a direct effect of water temperature on catch rates of albacore when inspect key areas with high concentration of catch. The high catch rates of albacore were highly related to low temperature in all layers. The wave form of declining trend of standardized CPUE from 1981~2009 suggested that both water temperature and fishing pressure may be effective on albacore. Therefore, the long term climatic trend is an important factor for albacore in addition to fishing pressures. |
