MID-PACIFIC OCEANOGRAPHY PART IX, 

 OPERATION NORPAC 



The need for a survey to provide a 

 synoptic picture of the oceanographic and bio- 

 logical conditions of the entire North Pacific 

 as a background for fisheries investigations 

 and for effectively describing the circulation 

 has long been recognized. It was also recog- 

 nized that such a survey would require the co- 

 operative and coordinated efforts of several 

 oceanographic activities and their vessels. A 

 proposal for such a cooperative venture, that 

 finally culminated in the quasi-synoptic survey 

 known as NORPAC, was made at the Fifth 

 Pacific Tuna Conference in November 1954. 

 Those present at the Conference represented 

 agencies of Canada and the United States in- 

 terested in tuna research and related oceano- 

 graphy. The Scripps Institution of Oceanography, 

 designated as the coordinating agency, was 

 instructed to enlist the aid of Japanese agen- 

 cies. After considerable planning and coor- 

 dination of the field programs, the vessels 

 from the various participating agencies com- 

 pleted the survey in July-September 1955. 

 Their tracks are indicated in the frontispiece. 



The Pacific Oceanic Fishery 

 Investigations (POFI) of the U. S. Fish and 

 Wildlife Service, Honolulu, T. H. , assigned 

 one vessel, the Hugh M. Smith (HMS) to the 

 NORPAC oceanographic survey, and one 

 vessel, the John R. Manning (JRM), to ex- 

 ploratory fishing during this period. The 

 Hugh M. Smith surveyed the area from the 

 Hawaiian Islands to 49°30'N. , from 157°30'W. 

 to 180 , during the period of July 15 through 

 August 28, 1955 (fig. 1). The data collected 

 on this cruise compose the main body of 

 this report. The John R. Manning fished in 

 the area northeast of the Hawaiian Islands be- 

 tween 15Z 30' W. and the west coast of the 

 United States from 30°N. to 47°N. (Appendix, 

 fig. 7) from July 15 through September 10, 1955. 

 The limited oceanographic observations of the 

 Manning , consisting of bathythermograph lower- 

 ings, surface salinities, and meteorological 

 records, are given in tables 9 and 10 (Appendix). 



NORPAC was opportunely timed in 

 reference to the POFI albacore research pro- 

 gram, a study financed by an allotment of 

 funds through the Saltonstall-Kennedy Act in 

 October 1954. This synoptic survey of the 

 oceanographic and biological conditions of 



the surrounding area as well as the particular 

 areas under study so early in the research 

 program should prove invaluable to the pro- 

 gress of these studies, for the oceanographic 

 and biological conditions of the albacore study 

 area can now be evaluated in reference to a 

 framework consisting of the entire North 

 Pacific Ocean. 



FIELD PROCEDURES 



The Smith departed Pearl Harbor, 

 T. H. , on July 15, 1955; stopped at Midway 

 Island from July 21-Z3 to take on water, fuel, 

 and stores; made a bait survey of the lagoon 

 and reef; completed her NORPAC observations 

 and returned to Pearl Harbor on August 28, 

 1955. The track and station— positions are 

 shown in the frontispiece and figure 1. 



A. Primary Missions : 



1. Oceanography 



a. Seventy-nine oceanographic 

 stations were occupied (fig. 1 and table 1). 

 At 67 of the stations 13-bottle casts were made 

 to a depth of approximately 1, 200 m. At 

 twelve of the stations deeper casts were made 

 to the maximum depth the wire would permit; 

 six were double casts of 9 and 13 bottles each 

 to approximately 2, 000-2, 500 m. and six were 

 13-bottle casts to approximately 1,400-1,500 



All Nansen bottles carried two 

 protected reversing thermometers. All but 

 the upper four bottles (those at approximately 

 100 meters or less) carried an unprotected re- 

 versing thermometer for use in determining 

 the sampling depth. 



1/ A station indicates a significant unit of 

 scientific work which is separated in time and/ 

 or space from other units. Table 1 lists the 

 observations made at each station. The follow- 

 ing observations did not constitute a station 

 and are tabulated separately: (1) trolling, (2) 

 single BT casts, (3) weather observations, and 

 (4) observations of fish, birds, and mammals. 



