37Z 



DISCOVERY REPORTS 



DAYLIGHT 



4-HOUR 

 PERIOD 



0600- lOOO 



lOOO - 1400 



10 



J 



13 



_1_ 



14 



I 



15 



_L_ 



17 



I 



STATION 



o- 







<t = 



' s s s ' - 



CI „ 



d (n J 



--to 



'T r) -o 



cr^-tO_^ — — rjttj 



s s 



ISO- 



2000000 CO OOI090200000 0000 000 (o) oiooooi 



(528) jCi^i'J ('f) L?! .''£? 



3 * 



597 



O 3 



O 

 O O 



^°0 O 38 5 



I" I O '°= O 



426 32 O 



O ° ' 



O I o 



o 



o o 



o 



984 4 348 



... O O 



DARKNESS 



■(.-HOUR 

 PERIOD 



100 



qSUN- 

 * , -SET 



2200-0200 



0200-0600 



■ I'l (M CO "1 



t -t i^ ct n 



O *o lO 



s s " s ? s 



en oi 



O *o m 

 m ^ o 



s s s 





O 30 O I O O O O O 2(0) 62 1 (330l 6 (31) 3 4298 O 4 O 4 

 (l2)_ Jf ^(195) 0_ 4M29 212 _36B_ J6_ J80_ J6 _4^9 _ (2278) 



990 

 -0--0- 



-0--0- 



2364 



O--22--0 



O 32 



O 



-2-0-- 



53 



* STATIONS FALLING IN THE GATHERING DARKNESS OF 



■f DEPTH UNCERTAIN 



MARCH , APRIL AND MAY 



Fig. 6i. Chart showing the day and night vertical distribution of the staple whale food as revealed by the South Georgia 

 plankton surveys of 1926-7 (N 100 H net hauls). The average gatherings from both surface and subsurface levels are shown 

 in the columns on the right, the night surface average being based on observations falling between sunset and sunrise 

 inclusive and on observations marked with an asterisk, the day surface average on observations falling between 0600 and 

 1800 hr. inclusive and on pre-sunset observations between 1800 and 2200 hr. Catch-figures for the surface refer exclusively 

 to the 0-5 m. layer and have been staggered for clarity. Figures in brackets show surface gatherings at stations where the 

 deep nets were not closed and the true subsurface position is unknown. 



hauling. At the same time I analysed our samples of the older population taken in the smaller three- 

 level horizontal (N 70 H) nets used at the same South Georgia stations (but not at exactly the same 

 time or in exactly the same water), plotting the results as for the larger nets.^ It will be seen that both 



1 To express the gatherings of the smaller diameter short-towed N 70 nets in terms of the gatherings of the larger N 100 

 all N70 catch-figures have been multiplied by the factor (30x2)/^ where 30 is the standard fishing time of the N 100 in 

 minutes, 2 a multiple allowing for the smaller mouth-opening (approximately half that of the N 100) of the N 70, and t its 

 fishing time, which in the vast majority of instances was 10 min. or less. 



[ 



