FISHERY BULLETIN: VOL. 69. NO. 3 



variables were measured on several cruises in 

 1966-68 within the Subarctic Region in con- 

 junction with studies of abundance and distribu- 

 tion of Pacific salmon (genus Oncorhynchus) . 

 Productivity data are listed in Larrance (1971), 

 zooplankton is discussed by Day (1970),' and 

 physical data are listed in Ingraham and Fisk 

 (1970). The objectives were to obtain an esti- 

 mate of annual productivity and to detect what 

 differences in levels of productivity, if any, 

 occurred among several oceanographic areas 

 identifiable by physical characteristics. 



METHODS 



Primary productivity and related variables 

 were measured on cruises of the RV George B. 

 Kelez in March, June, and September 1966; 



' Day, D. S. 1970. Distribution of zooplankton from 

 the mifl-Subarctic Region of the Pacific Ocean, 1966-67. 

 Natl. Mar. Fish. Serv., Biol. Lab., Seattle, Wash. Unpubl. 



manuscr. 



January-February, June-July, and August 1967; 

 and May 1968 ; and on a cruise of the MV Par- 

 agon in June 1966 (Table 1). Measurements 

 in 1966-67 were south of Adak Island (long 

 176°25' W) except in January-February 1967 

 when the cruise track was along long 162° W 

 and in May 1968 when it was along long 165° W 

 ( Figure 1 ) . Primary productivity was measured 

 by the carbon-14 method introduced by Stee- 

 mann Nielsen (1952) and modified by Strick- 

 land and Parsons (1965) . Productivity stations 

 were normally taken shortly before dawn and 

 local apparent noon (LAN); incubation periods 

 were for one-half the daylight period, i.e., from 

 dawn to LAN and from LAN until about twi- 

 light. Seawater was sampled with 6-liter plastic 

 water bottles at depths determined from the 

 penetration of light below the sea surface. These 

 "light depths" were 100, 61, 35, 18, and V/( of 

 the surface intensity according to the fractions 

 of light transmitted by neutral-light filters used 

 in the productivity incubations. The depths 



Table 1. — Summary of areas, dates, and stations on which primary pro- 

 ductivity was measured, 1966-68'. 



* Only portions of cruises discussed in this report are included in Table I. 



^ Data from cruise 6-67 were averaged with data from station 5-67 for this report. 



596 



