NOTE Hazin et al.: Distribution and relative abundance of Prionace glauca 



475 



(ANOVA) was performed to determine whether blue 

 shark CPUEs were significantly different among 

 months. The mean CPUE for each month was calcu- 

 lated and all monthly mean CPUEs were then com- 



pared by ANOVA, through one-way classification of 

 data. The months were the only independent vari- 

 able (Table 3). No CPUE data were available from 

 October 1990 and from January and April 1991. Data 

 on the sex of the specimens were not available from 

 January to October 1991. 



All lengths are reported as fork length (FL), which 

 was measured from the tip of the snout to the fork of 

 the tail. Blue sharks were always measured at the 

 time of landing. Length data were available only for 

 1990 and 1991. To better understand seasonal varia- 

 tion in CPUE, CPUE data for the various age classes 

 of male specimens from February through Decem- 

 ber 1990 were evaluated. Females were not included 

 because they were present only from February to 

 July. To calculate the age-CPUE distribution, male 

 blue shark lengths were converted to age by Stevens' 

 (1975) growth equation, as follows: 



L< = 423(l-e-° 11,t+1035) ) 



3°S 



4°S 



5°S 



6°S 



37°W 



3 S ° W 



33°W 



100°W 80°W 60°W 40°W 2fl°W 0° 20°E 



Figure 1 



Location of the fishing ground (hatched area) and central positions of the longline sets made by 

 the FV Argus from August to December 1987 and from February 1990 to December 1991, in the 

 southwestern equatorial Atlantic Ocean. 



