| 英文摘要 |
The catches of Taiwanese squid jigger were primarily from the waters of southwestern Atlantic (SWA), in which the amount counted to 90% of total squid catches. This study applied geostatistics techniques to analyze logbook data aiming to quantify the spatial distribution pattern of Argentine squid in SWA, and further used the outcome to estimate annual available catch. We estimated that the average value of CPUE is 10,400 kg d-1v-1，with a maximum of 19,221 kg d-1 v-1，in 1999 and a rather high amplitude of 20%-180%. Observing the sea surface temperature (SST) indicated that the minimum average SST was 9.8 oC found in 1999, and the maximum was 13.2 oC occurred in 2004 when the lowest catch recorded. Analysis of variance results indicated that categories of year, month and position on the shelf have significant effect, but the latitude category was insignificant. Homogeneity tests turned out 4 homogeneous groups; 1) ordinary year including 1995，1996，1998，2001, 2002 &2003, 2) low abundance year of 2004, high abundance year of 1997 &2000, and the exceptional high abundance year of 1999. Using geostatistic technique to analyze fortnight-period catch and SST data indicated large amount of spatial variations indicating significant spatio-temporal variation. In particular in the lowest catch of 2004, we found the exceptional SST was prevailing on the fishing ground after the second fortnight period; widespread high temperature may linked to low catch rate or low abundance. Moreover, we used distribution maps to visualize spatial pattern, calculated Moran’s I to quantify spatial auto-correlation and model experimental variogram to describe underlying process. For example, in 2004 the distribution of CPUE pattern reflected a very short range of 2.43 degree, with a high nugget effect and a small value of variogram scale; which indicated a very thin population with high uncertainty. The estimated total available catch exhibited that low exploitation rate was general status before 1998, and conversely high exploitation or over-exploitation was considered after 1999. |
