The longitudinal standard deviation of catch 

 tends to decrease at a rate of 0.27 degree (16 

 miles or 30 km.) per year, whereas that for 

 CPUE tends to increase, slightly, at a rate of 

 0.04 degree per year. The latitudinal standard 

 deviation of catch has an intercept of 1.93 de- 

 grees (about 114 miles or 211 km.) and in- 

 creases at a rate of 0.01 degree (about 1 mile 

 or 2 km.) per year, whereas the latitudinal 

 standard deviation of CPUE has an intercept ot 

 2.29 degrees (about 137 miles or 254 km.) and 

 increases at a rate of 0.11 degree (about 7 

 miles or 13 km.) per year. The correlation 

 coefficient indicates that the distributions of 

 both catch and CPUE are oriented, slightly, in 



a northeast-southwest direction in 1949; rotate 

 to an east-west orientation in 1955; and after 

 1955 continue to rotate in a clockwise direction 

 toward a northwest-southeast orientation. 



Average Location 



This section considers the average location 

 of effort and albacore CPUE inferred from av- 

 erages of the CPUE and effort first-order spa- 

 tial statistics for each month. Figures 14 and 

 15 show the average positions of the first mo- 

 ments of effort and CPUE for each month. The 

 average CPUE moment (fig. 14) is located at 

 long. 164° E., lat. 33° N. in November and 

 moves south and west to long. 147° E., lat. 29° 



s 

 o 



s 



r 



Figure 10. --Spatial statistics for CPUE 1949-51 on the North Pacific albacore 

 longline grounds. The heavy line represents the peak fishing period from 

 December to March. --Cont i nued . 



15 



