mobile. Herds of common dolphins off southern Cali- 

 fornia and Baja California may move as far as 120 km in 

 a 24-h period, following underwater escarpments (Evans 

 1971, 1974). 



Preliminary results of our tagging program through 

 early 1974 have been previously published (Perrin 1975). 

 Time at liberty for tagged spotted dolphins ranged from 

 1.7 h to 502 days and minimum distance traveled from 13 

 to 532 km. 4 The tentative conclusion was that these data 

 indicate a great deal of east-west and north-south move- 

 ment within the eastern portion of the range of the off- 



4 A maximum value for minimum distance traveled of 2,415 km was 

 given in Perrin (1975). Subsequently, additional information has been ac- 

 quired concerning the recapture of that tag, and the data are now consid- 

 ered to be unreliable and are not included in the analysis below. 



shore race of S. attenuata. Tag returns for S. longirostris 

 showed less net movement. 



MATERIALS AND METHODS 



During the course of research on the dolphin/tuna 

 problem, 3,712 small cetaceans were tagged (Table 1), 

 including 2,996 spotted dolphins (Fig. 1) and 324 spinner 

 dolphins (Fig. 2). One of us (Evans) carried out other dol- 

 phin-tagging operations during the period 1969-76, but 

 these did not involve Stenella spp. and will be described 

 in another report. Several types of tags and tag legends 

 were used: 



1. Spaghetti tag with plastic dart. This tag was de- 

 scribed and figured by Nishiwaki et al. (1966). The 



Table 1.— Dolphins and small whales tagged, 1969-76. Radiotags 

 included. 





Stenella 



Stenella 



Delphinus 



Tursiops 





Uniden- 





Year 



attenuata 



longirostris 



delphis 



truncatus 



Other 



tified 



Total 



1969 



207 



11 



















218 



1970 



618 



94 



10 











'46 



768 



1971 



147 



18 



50 



12 



2 1 



3 15 



243 



1972 



306 



41 



28 



19 



2 7 







401 



1973 



203 



35 



56 



8 



•2 



1 



305 



1974 



1,048 



70 



23 



72 



2 7 



1 



1,221 



1975 



336 



46 



26 



2 



s 4 



32 



416 



1976 



131 



9 



















140 



Total 



2,996 



324 



193 



113 



21 



65 



3,712 



'Probability is high that these were either spotted dolphins, Stenella at- 

 tenuata, or spinner dolphins, S. longirostris. 



•'Pacific white-sided dolphin, Lagenorhynchus obliquidens. 



'Spotted or spinner dolphins. 



4 Striped dolphin, Stenella coeruleoalba. 



■Two striped dolphins and two short-finned pilot whales, Globicephala 

 macrorhynchus. 













1 1 1 1 1 1 1 1 1 





















"V 



\ 





























■«, 









-_ 











Stenella attenuata 





















- 



^ 





-- 



















































\ 











20° 





s, 















































1 





4 













> 



am 



IsiO 



a 1 



; 































12 



28 



32 



63 







15 





.... \v-~d 4 TV ■SA™ 















































I 



20 



176 



59 



39 





8 



28 



41 





7 



i 



















































2 



1 



19 



10 



5 



24 



S4 



81 



6t 



14 















































5 





9 



33 



1 





3 



1 



1941 



1 



15 



II 



2C 



34 



3 



51 



16 



■v. 



\ 



I jO 





IO» 



















7 





6 



13 



41 





3 



8 



18 



45 



17 



6 



3 



12 



31 





II 



145 



54 



39 



1 



6 



20 



36 



6 



12 



29 





\ 



J- ^ 























6 





9 



8 



32 





17 





8 



.8 





10 



44 



62 





9 



3! 



46 



92 



67 



88 



116 



56 



22 





II 



16 



\ 



\ 



&^V 











































II 







3 





7 





1 



8 



1 



27 



19 



24 



28 



9 









39 



2 



4 





' 



I 



































































9 



50 



7 







34 



12 



II 



4 















































































1 





39 



14 



1 



1 



( 





0° 



































































2 







1 



1 



5 



6 





J> 



































































Gal 



»w 



ffOS 



Is 



*J 



» 









( 



P 























































3 































\ 





















































































1 





It 



>0° 



1 









30 









U 



to 



1 







: 













i; 



c 









i 



0° 



1 



T 





IC 



»• 



T 1 



1 



1 



9 



T 



1 



T 



T 



8 



& 



nun? 



0° 



Figure 1.— Number of releases of tagged spotted dolphins, Stenella attenuata, by 2-degree area, 1969-76. Re- 

 leases given in Table 1 for which precise localities are not available are not included. 



