Distribution of Salmon and Related Oceanographic 

 Features in the North Pacific Ocean, Spring 1968 



By 



ROBERT R. FRENCH, RICHARD G. BAKKALA, MASANAO OSAKO," and JUN ITO 1 



Fishery Biologists 



National Marine Fisheries Service Biological Laboratory 

 Seattle, Washington 98102 



ABSTRACT 



Japanese and United States research vessels made a cooperative research cruise. Dif- 

 ferences in distribution of salmon were examined by species, by maturity, and by age group. 

 Sockeye salmon, Oncorhynchus nerka, were in the more northerly waters and pink salmon, 

 0. gorbuscha, in the more southerly waters, whereas chum salmon, 0. keta, were more widely 

 distributed and in all waters occupied by other species. The proportion of older ages de- 

 creased from north to south; immature sockeye and chum salmon were generally restricted 

 to the more southern waters and maturing fish to the more northern waters. 



The distribution of larval fish, which at times serve as food for salmon, varied by group; 

 Hexagrammidae were in all waters occupied by salmon whereas larvae of Hemilepidotus 

 and Bathymaster were taken only in the northern areas and Myctophidae larvae only in the 

 southern areas occupied by salmon. 



INTRODUCTION 



Each year since 1955, Japan and the United 

 States (as members, with Canada, of the Inter- 

 national North Pacific Fisheries Convention) 

 have been independently investigating the dis- 

 tribution of salmon, Oncorhynchus spp., on the 

 high seas. The purpose of the research is to 

 determine the ocean distribution, abundance, 

 and migration of salmon and to answer pert- 

 inent questions raised by the Commission under 

 the provisions of the Convention. To cover 

 more area in a single coordinated effort, Japan 

 and the United States joined in a cooperative 

 research cruise in spring 1968 to clarify the 

 relation between salmon distribution and ocean- 

 ographic features south of the Aleutian Islands. 

 Japan made similar research cruises in 1967. 

 The joint cruises are scheduled to continue in 

 subsequent years. 



1 Fisheries Agency of Japan, Far Seas Research 

 Laboratory, Shimizu, Japan. 



Two Japanese vessels and one United States 

 vessel participated. The Wakashio Maru fished 

 from April 30 to May 24, and the Hokko Maru 

 was on fishing stations from May 9 to 24. The 

 U.S. vessel George B. Kelez fished from April 

 18 to June 15. Figure 1 shows the fishing 

 stations of the three vessels. 



This report details fishing and oceanographic 

 results of sampling in a wide area of the North 

 Pacific Ocean and presents data on the relation 

 between salmon distribution and oceanographic 

 features. 



METHODS AND EQUIPMENT 



Fishing gear and oceanographic equipment 

 varied between Japanese and United States 

 research vessels. 



Fishing Gear 



Japanese research vessels used gill nets and 

 longlines as fishing gear. The research net 



