en route to and from the area. The Master of 

 the Paragon was directed to complete the re- 

 quired fishing between July 20 and September 10, 

 1958. The required fishing consisted of either 

 (l)sufficient sets of 7-1/2- to 8-1/2-inch (stretched 

 measure) mesh gear to total 1,200 shackles or 

 (2) an albacore catch of 60 tons. 



The Paragon departed from Seattle, 

 Washington on July 16, 1958, and arrived in the 

 survey area on July 26, 1958. The 1 ,200-shackle 

 fishing requirement was completed on August 30, 

 1958, and the vessel returned to Seattle on 

 September 5, 1958. The track is shown in the 

 frontispiece. 



FIELD PROCEDURES 

 Biological Studies 



Exploratory fishing . --Nineteen gill -net 

 sets (tables 1 and 3 and fig. 1) were made from 

 the Hugh M. Smith during 28 nights of operation 

 in the band of 53°-66°F. surface temperatures 

 which past cruises had shown to approximate 

 the latitudinal limits of the mid-ocean albacore. 

 The remaining nine nights were lost because of 

 unsuitable weather at setting time. On only one 

 of these nights did the weather moderate enough 

 so that it would have been possible to retrieve 

 the net at dawn without excessive damage. At 

 two of the stations the wind and sea increased 

 during the night. At station 61 the seas rolled 

 or tangled the net to such a degree that only 

 1/3 of the net was fishing properly when it was 

 retrieved. At station 68 the net was retrieved 

 in winds having gusts up to 26 knots and the net 

 was so badly damaged that 2 days were required 

 to repair it. Thus, the number of nights that 

 were suitable for gill netting was 18 out of 28 

 or about 65 percent. 



Each of the sets fromi the Smith con- 

 sisted of 10 shackles of 4 -1/2 -inch to 7 -1/2 -inch 

 (stretched measure) mesh gill net. The con- 

 struction details of this gear have been described 

 by Graham and Mann (1959). At the first six 

 stations (those between stations 22 and 40) each 

 set consisted of one 4-1/2-, one 5-1/2-, four 

 6-1/2- , and four 7-1/2- inch mesh shackles. 

 With the completion of these stations the usable 

 shackles of 7-1/2-inch mesh gear had been 

 reduced to three, so the number of 6-1/2-inch 

 mesh shackles was increased to five. 



Albacore were taken in seven of the gill- 

 net sets, with a total catch of 97 fish. The 

 largest catches were 49 eilbacore at station 67 

 (42°7'N., 175°08'W.) and 26 at station 63 

 (43°29'N., 174°48'W.) (table 3 and fig. 1). 



HUGH M SMITH CRUISE 46 



• GILLNET STATION 



* LONGLINE STATION 

 AL ALBACORE 

 SJ SKIPJACK 



^' 



OAHU 



-D 



60° 



50» 



40" 



30° 



20° 



180° 



170° 



160° 



Figure 1. — Track chart, Hugh M. Smith cruise 

 46, July 21 to September 9, 1959, showing gill- 

 net and longline stations. Letters and solid 

 lines designate the location of temperature 

 sections shown in figures 4 to 13. 



Second sets at these stations produced 7 and 3 

 albacore, respectively. Catches at the other 

 three stations were 3, 4, and 5 albacore. 

 Catches of species other than albacore tuna are 

 also listed in table 3. Five lines were trolled 

 from the Smith_ during daylight hours, at a 

 speed of 6. 5 knots, when in areas having surface 

 temperatures between 52° and 72 °F. Two lines 

 were trolled at standard speed (9 knots) during 

 daylight hours in all other areas. Within the 

 52°-72°F. surface temperature range it was 

 occasionally necessary to reduce the number of 

 lines to avoid tangling during rough weather or 

 to increase to standard speed after longline 

 stations or between north-south transects in 

 order to obtain the desired gill-net station 

 spacing. The trolling results are summarized 

 in table 5. 



