60°N. 



60°N. 



55° 



50° 



45° 



40° 



35° 



Figure 1. — Stations fished by Japanese and United States research vessels in spring 1968. 



string (standard combined mesh net) consisted 

 of 10 tans (a tan is 50 m. long) each of five 

 mesh sizes— 55, 72, 93, 121, and 157 mm. At 

 some stations, 30 tans of a commercial mesh 

 size for salmon (121 mm.) were added to the 

 string. At most stations the longlines to catch 

 fish for tagging and for comparison with gill 

 net catches were fished along with the gill nets; 

 either 20 or 30 hachi were set at a station (one 

 hachi has 49 hooks). 



The U.S. vessel fished 30 shackles (one 

 shackle is about 91 m.) of gill nets of five 

 mesh sizes— 63, 82, 98, 115, and 133 mm. For 

 experimental purposes two shackles of mono- 

 filament mesh (133 mm.) were added to the 

 string, and on a few occasions five shackles 

 of gear were attached below five surface nets 

 of similar mesh sizes to sample at depth. 



Oceanographic Equipment 



The Wakashio Maru took BT (bathythermo- 



graph) readings, and the Hokko Mam, in ad- 

 dition to BT readings, measured temperatures 

 with reversing thermometers and took salinity 

 observations to 300 m. with a water sampler. 

 The George B. Kelez used an STD (salinity, 

 temperature, depth) instrument to obtain 

 oceanographic data. 



ENVIRONMENTAL CONDITIONS 



The horizontal distribution of water tem- 

 perature at 100 m. indicated a slightly different 

 distribution of 2° C. water in 1968 compared 

 with 1967 (fig. 2). The area of cold water 

 was between the Transitional Domain to the 

 south and the Alaskan Stream Area to the 

 north. In 1968, water was not colder than 

 2° C. east of about long. 165° E., whereas in 

 1967 the cold water originating from the West- 

 ern Subarctic Domain intruded well east of 

 long. 170° E. at lat. 47° to 48° N. Temperature 

 data near long. 170° E. were obtained from 



