during an additional five minutes. The 

 trawl was made at this time becsiuse upon 

 completion of setting the nets and observing 

 the hydrographic routine, generally fog or 

 rough weather made it inadvissible for the 

 vessel to cast off from the nets. 



After the nets were set, the observers 

 completed the following routine: 



Deep cast — Four Nansen bottles, each 

 carrying two protected deep-sea reversing 

 thermometers cind one unprotected, were 

 cast to 400, 500, 700, and 1050 meters. 



1. BT lowering — to 275 meters. 



2. Shallow cast—procedure the Scime 

 as at the primary station, except 

 that the bottom bottle was gener- 

 ally cast to 325 meters. Near the 

 end of the season and en route to 

 Seattle, the depth of the bottom 

 bottle was changed to 525 meters. 



Usually additional BT's were taken 

 between the primary and secondary stations, 

 and drift bottles were released at desig- 

 nated locations shown in table 1. 



Shallow cast — Ten Nansen bottles, all 

 carrying two protected thermometers and 

 the bottom six carrying one unprotected 

 also, were cast to 10, 25, 50, 75, 100, 

 125, 150, 200, 250, and 300 meters. 



Surface observation — The temperature 

 was recorded from a bucket sample by using 

 a O'-ao" C. dipping therncmeter with 0.1" 

 subdivision. 



LABORATORY PROCEDURE 



BT lowering- 

 meters. 



-The BT was lowered to 275 



Water samples — Dissolved-oxygen sanqsles 

 were drawn from all Nansen bottles into 

 standard dark bottles and fixed immediate- 

 ly. Chlorinity samples were drawn from 

 all Nansen bottles and taken from the sur- 

 face bucket into standard citrate-type 

 bottles. 



Plankton hauls — VerticEil hauls were 

 made with a standard 1/2-raeter net, #6 

 mesh, at about 50 meters per minute from 

 150 and 300 meters to the surface. The 

 Scunples were treated with 10 percent for- 

 malin neutralized with sodium borate. 



Upon completion of the above routine, 

 in the evening after dark, if weather condi- 

 tions permitted, the trawl was towed at the 

 surface in the vicinity of the gill nets at 

 three knots for 15 minutes. 



The primary station routine usually 

 began about 1600-1700 zone time and was 

 coD^leted by 2400. 



Chemistry 



Chemical analyses were performed in 

 Adak and Seattle. Through the cooperation 

 of the U. S. Navy, a temporeiry laboratory 

 was established in Adak, where the early 

 chlorinity samples were analyzed. Later 

 samples were returned to Seattle for analy- 

 sis. All oxygen samples except those col- 

 lected on the return voyage were zmlyzed 

 in Adak, thus resulting in an average delay 

 of two or three weeks between sampling and 

 analysis. 



Chlorinity and dissolved oxygen were 

 determined by titration by using the Knudsen 

 and Winkler methods respectively. 



Observed Data 



Station No. — The chronological order 

 in which the stations were taken. Equiva- 

 lent gill net sets are listed in Summaries 

 of Observations. 



Position — Latitude and longitude deter- 

 mined by Loran readings at all positions 

 and supplemented by celestial sights in some 

 positions. 



Time — The date and hour (GCT) at which 

 the messenger was released. The second 

 hour indicates the time of the second cast 

 or, in case of more than two casts, the time 

 of the final cast. 



The secondsiry station routine, observed 

 at midway points between the fishing loca- 

 tions which were usually 60 miles apart, 

 usually occurred at noon and resulted in 

 observations at intervjils of 30 miles: 



Weather observations — Coded values as 

 presented in HO 606-C, Bathythermograph 

 observations . 



Barometer — Readings from shipboard 



