Six days were spent in the Marquesas 

 scouting for bait or in running between islands 

 maintaining a lookout for tuna schools and with 

 surface trolling lines out. Only 4 schools of tuna 

 (2 skipjack and 2 unidentified) were sighted close 

 to the islands. 



Four night-light collections were obtained 

 while at anchor in the Marquesas Islands. 



A small sardine, Harengula v i 1 1 a t a , 

 which occurs in the bays and along the coasts of 

 the Marquesas Islands apparently at tinnes in 

 marked abundance, was found to be scarce during 

 the period of our survey. With considerable 

 effort about 130 buckets of these fish were ob- 

 tained which we hoped to bring back for stocking 

 in Hawaiian waters. Although the majority were 

 lost at sea during rough weather, about 20 

 buckets of the sardines survived and were re- 

 leased along the leeward coast of Oahu. 



General 



A total of 746 bathythermograph lowerings 

 were nnade during the cruise. 



Water color (Forel scale) andSecchi disc 

 visibility measurements were obtained at most 

 daytime plankton stations. 



Standard marine weather observations 

 were made 4 times daily, encoded, and trans- 

 mitted whenever possible to the Weather Observ- 

 er, San Francisco. 



Morphometric measurements were 

 performed on 5 yellowfin and 2 skipjack caught 

 by surface trolling. 



The wheel watch maintained a lookout for 

 tuna schools and bird flocks during all daylight 

 hours that the vessel was underway; 45 tuna 

 schools were sighted, most of which were thought 

 to be skipjack. Surface trolling during daylight 

 hours yielded poor results; the total catch for 

 the cruise consisted of 1 3 dolphin. 5 wahoo, 

 skipjack, and 2 black skipjack. 5 yellcTVvfin " 



In addition to the regular wheel watch, a 

 1 -hour bird watch was maintained (by King) each 

 day at 1600-1700 throughout the cruise; on the 

 westbound leg a similar watch was carried out 

 by Pyle) each morning at 0600-0700. All birds 

 sighted were counted and identified as accurately 

 as was possible. 



The activities conducted at each station 

 and the data resulting from the various biological 

 and oceanographic observations are listed in 

 tables 2-12 which are assembled immediately fol- 

 lowing the text of this report. Figures appearing 

 at the end of the report include the temperature - 

 depth sections drawn from the BT data; the 



station curves for each of the oceanographic 

 stations; and the vertical sections, surface to 

 500 m., for salinity, thermosteric anomaly, 

 oxygen and phosphate, and geopotential topogra- 

 phy. 



FIELD PROCEDURES 



In this report we shall give a rather 

 complete description of equipment and techniques 

 employed in EASTROPIC since Sonne of the 

 nnethods used were new to POFI cruises and not 

 described in previous publications. 



Zooplankton 



Except on the runs to and from Honolulu 

 and Manzanillo, two plankton stations were oc- 

 cupied each day, one between 0900 and 1100 and 

 the other between 2100 and 2300 hours. All 

 hauls were made with 1 -meter (mouth diameter) 

 nets of 30XXX silk grit gauze (apertures 0.65 

 mm. in width), using a wire rope cable of 1/4- 

 inch diameter. 



Four types of hauls were employed. A 

 closing -net haul (1) with 3 nets sampling simul- 

 taneously at 3 levels together with a single, 

 open-net, oblique haul (2) to about 200 meters' 

 depth, were carried out routinely at each morn- 

 ing and night station. At 16 of the morning 

 stations there was an additional haul (3) with a 

 closing net sampling obliquely between about 

 200 and 300 meters. A short series of 20- 

 minute , surface hauls (4) were taken in con- 

 junction with an oceanographic "front." Except 

 in this latter series, on each of the hauls the 

 nets were operating for approximately 30 min- 

 utes. The amount of water strained on each 

 haul was measured by a flownneter suspended in 

 the mouth of the net. The flowmeters were 

 calibrated before and after the cruise. The 

 sampling depth was recorded on 35 hauls by 

 means of a depth gauge of the type described by 

 Miller, et al. (1953) . The number of quantita- 

 tive samples obtained and the number of 

 successful hauls completed for each type of haul 

 are shown in table 1 . 



200-Meter Oblique Hauls 



The nets used and the method of hauling 

 have been described by King and Demond (1953). 

 A depth gauge employed on 12 hauls indicated 

 that the actual depth reached exceeded the 200- 

 meter calculated depth, assuming that the towing 

 wire described a straight line , by about 25 per- 

 cent. The depths shown in table 3 are the 

 corrected depths which for the 115 successful 

 hauls averaged 231.4 meters. 



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