英文摘要 |
一、The results indicated (1) the effort distribution for hook per basket of Taiwanese logbook data indicated two modes, and the most effort was separately found in 10 and 15-18 hooks; the bigger catch rate of albacore was obtained by 6-13 hooks, but the catch rates of 8-20 hooks are all high; (2) the CPUEs obtained from standardization for all years and three different periods were similar. The yearly standardized CPUE declined sharply at the beginning of the fishery before mid-1980s, and then continuously declined up to mid-1990s, thereafter, it lightly increased and remained relative stable till present date. Similar trends were also obtained for the quarterly standardized CPUE series; (3) the main age of Taiwanese catch of albacore got bigger from 1981 to 2013; the main age of Taiwanese catch was 5-8 from 1981 to 1997, the one was 6-10 from 1999 to 2006, and the one was 7-11 from 2007 to 2013. In general, albacore caught in area 32 is bigger than caught from area 31. The majority of Taiwanese catch of albacore is greater than age 3 in area 31 and is greater than age 4 in area 32; (4) the effects on change of parameters in ASPM showed (a) that the better fitting was obtained as the cpue trend of the second period (1987-1997) from Taiwan was excluded, (b) values of MSY obtained from different natural mortalities (0.2, 0.25, 0.3 and 0.35) were similar, but the one obtained from 0.4 natural mortality was significant different; as the cpue trends obtained from Irish and Spanish _BB were exclude in analyses, the better fitting were obtained; (5) the effect on change of parameters in ASPIC showed that the fitting was significant effected by the initial value of B1/K, but was hardly effected by the other parameters (Hsieh, 2013). CPUE series will also affect the result of ASPIC analyses. |