HORIZONTAL DISTRIBUTION, GROWTH AND DYNAMICS OF DISPERSAL 397 



(3) In both young and old swarms the pattern of modal values displayed is heterogeneous 

 throughout the season. 



(4) In January the yearling swarms tend to fall mainly within a length range of 17-40 mm., the 

 more backward of them, as, for instance, at Stations WS 537, WS 540 and WS 542, having not yet 

 quite outgrown their early adolescent (11-20 mm.) phase. In February the yearling swarms tend to 



66 



64 



S60 



O 56 



,■5 52 



548 

 S 44 



- 35 



UJ 



a 32 

 <2e 



■^24 

 ^20 

 il6 



JANUARY 



FEBRUARY 



6 7 8 B ro 1010 10 II r6 17 19 19 I9 202020 2I 21 21 22 22 2425 26 27 27 27 27 27 27 27 27 27 27 27 2B 28 28 303030| 3 57899999 



795 575 S 2168 2I70 815 I270 818 2198 B20 W373 312 W538W540W540 824 2SS8 2560W542 2562 2567 1673 I507 351 352 354 



797 799 5B0 2168 BI3 602 2195 2197 305 2199 2547 W537 W540W540W540 2558 2559 2561 825 1665 2567 1675 349 351 354 



|^~] WEDDELL DRIFT 

 Scale per cent 



EAST WIND DRIFT 



(8) 

 (l){3X6){lX2)(8) 



N 2 MEAS- 

 URED 



702 69 325 61 148 48 125 432 174 77 lOO 32 86 522 539 95 19 172 lOO 55 818 185 lOO 55 60 III 

 51 159 23 87 53 53 167 79 20 467 246 116 588 904 504 35 36 346 171 205 146 82 35 36 82 



MONTH 



DATE 



STATION 



68 



64 (/) 



603 



55 g 



52" 



48 I 



44^ 



40z 



3*UJ 

 32 O 



28 < 



24°= 



20f 



15 i 

 12 y 



8 

 N2 MEAS- 

 URED 



FEBRUARY 



MARCH 



1 17 18 IB 20 21 21 22 22 23 23 23 24 24 26 26 27 28 29 1 I 2 3 4 4 5 5 5 6 8 8 10 10 lO lO 12 14 14 15 15 17 19 21 22 23 23 24 24 25 26 26 

 2226 222a 624 W152 627 2244 1537 2590 1544 1297 1547 2268 2271 2506 368 540 643 1154 24 2000 38 1713 1715 1717 1720 

 I 618 522 1531 2BI4 1535 1285 WI56 1543 W9I5 2594 2600 2503 2606 2274 368 643 2614 23 200O2004 1711 2295 1717 1719 558 



Scol c per cent 



Scole per cent 



WEDDELL DRIFT 



Scale per cent 



(2) 

 (2X0 



;-50 144 85 200 71 lOO lOO 153 50 388 lOO 75 42 471 60 342 70 

 533 50 lOO 100 47 146 ISO 100 118 lOO 630 176 276 415 143 33 21 



17 109 269 84 153 lOO 465 57 134 95 

 lOO 47 75 22 527 91 164 77 241 231 



DATE 

 ST 



58 



54 (/I 

 50% 



55 g 

 52 O 



482 



40z 



36 ~ 



u 

 32 o 



28 5 



24"^ 



20 £ 



,6^ 



12 Ul 



e 



N2MEAS- 

 URED 



Fig. 136. Developmental condition of the small and staple whale food in summer. For vertical scale 



see legend to Fig. 107. 



fall mainly within a length range of 25-44 min., although exceptionally, as for instance at Station 151 1, 

 backward swarms may be encountered with a dominant length range of only 21-28 mm. In March the 

 yearling swarms tend to fall mainly within a length range of 33-48 mm., although again exceptionally, 

 as for instance at Station 658, surprisingly backward swarms may be encountered late in the month in 

 which the females are still in stage i and the length range still dominantly 21-28 mm. as in February. 



(5) Throughout the season the adult swarms fall dominantly within a length range of 44-60 mm., 

 the majority of them, however, in the 48-56 mm. range. 

 (b) Southern zone 



(i) As in the northern zone the staple whale food is represented by a heterogeneous assemblage 

 of yearling and adult swarms, the former, however, slowly outgrowing their early adolescent phase 

 and in many instances persisting until well into March with the small whale food as an important 

 or dominant component of the swarm length range. 



