3?2 DISCOVERY REPORTS 



been recovered more than 50° of longitude east or west of the position of marking (the maximum 

 recorded dispersal for Fin whales), No. 5456 having moved through almost 87 of longitude (86° 58'), 

 from Area IV westwards into Area III. It seems probable, therefore, that Blue whales disperse over 

 greater distances than Fin whales, but since the number of recoveries is so small, it is not possible 

 to say whether or not the range of dispersal may be limited as appears to be the case in Fin whales. 



RANGE OF DISPERSAL 

 DEGREES WEST DEGREES EAST 



90 80 70 60 SO 40 30 20 10 10 20 30 40 50 GO 



3 5 



J i i_ 



_l l_ 



0-1-2 GROUPS 



H-n 



Hx 



EX 



XX 





_i i i — i — i — 1_ 



r~i 



n 



n 



XX 



Fig. 13. Dispersal in time — Blue whales — actual numbers of marked whales recovered in all areas. 



RANGE OF DISPERSAL 

 DEGREES WEST DEGREES EAST 



90 80 70 60 5C 40 30 20 10 10 20 30 40 50 60 



1 1 1 1 1 



5 - 



0-1-2 GROUPS 





j-_L 



3-4-S GROUPS 



r^— 1 



£ 10 - 11-12-13 GROUPS 



n n 



L 



XX. 



Fig. 14. Dispersal in time — Blue whales — corrected numbers of marked whales recovered in all areas. 



For a comparison of dispersal after different periods the actual numbers of recoveries shown in 

 Fig. 13 are divided into three year-group series in the same way as was done with the Fin whale 

 recoveries, the corrected numbers recovered in the various year-groups are similarly shown in Fig. 14. 

 In the 0-1-2 groups 46-5% of the whales have moved less than io° either way. The recoveries made 

 in later groups suggest that, as in Fin whales, the proportion which have not dispersed is less in the 

 long-term than in the short-term recoveries, but the small number of marks returned does not 

 permit a definite conclusion to be drawn. 



