EXPERIMENTAL FISHING TO DETERMINE DISTRIBUTION OF SALMON 

 IN THE NORTH PACIFIC OCEAN AND BERING SEA, 1956 



by 



Mitchell G. Hanavan and George K. Tanonaka 



U. S. Fish and Wildlife Service 



Seattle, Washington 



ABSTRACT 



Five vessels were employed from May to October 1956 to study the 

 distribution of Pacific salmons in the North Pacific Ocean and Bering 

 Sea. The operation was designed to (1) provide samples of fish for 

 racial identification, (2) provide evidence of seasonal movements and 

 changes in the distribution of salmon and (3) study the ocean habitat 

 and conditions that control the distribution, movement and survival 

 of salmon. 



The area of operation was approximately 2,000,000 square miles 

 extending from the coast of Washington and Oregon to longitude 175° 

 E. and from latitude 43° N. to 60° N. Within this area 195 gill net 

 sets resulted in the capture of 7,963 salmon. 



Salmon were measured aboard the vessels before freezing. Length 

 frequencies are shown graphically by species and area and in relation 

 to the mesh size in which the fish were capture. 



INTRODUCTION 



The United States Fish and Wildlife 

 Service as a research agency of the Inter- 

 national North Pacific Fisheries Commission, 

 is engaged in a study to determine the ex- 

 tent of intermingling in the North Pacific 

 Ocean and Bering Sea of Asian and North 

 American salmons. In part this program re- 

 quires (1) the collection of large samples 

 of salmon from an extensive oceanic axea 

 and the preservation of these saunples for 

 racial analysis, (2) detection and measure- 

 ment of seasonal movements and changes in 

 the distribution of salmon and (3) the study 

 of the ocean habitat and the conditions 

 that control the distribution, movement and 

 survival of salmon. 



The report which follows describes the 

 cruises and operations of five vessels 

 engaged in this program during the 1956 sea- 

 son. They include four schooner-type ves- 

 sels, the Tordenskjold , Mitkof , Paragon , and 

 Celtic^ chartered by the Branch of Fishery 



Biology- , Fish and Wildlife Service, and 

 the John N. Cobb, operated by the Explora- 



2/ 



tory Fishing and Gear Development Section -' 

 of the Service. 



Figure 1 shows the pattern of this 

 extensive fishing and oceanogr aphic opera- 

 tion, the stations fished by the five ves- 

 sels, and the distribution of salmon, 

 steelhead and albacore during the period 

 of the study, which extended from mid-May 

 until the first week in October. 



During this 4 1/2-month period there 

 was 195 gill net sets in a sampling area of 

 approximately 2,000,000 square miles. The 

 total salmon catch was 7,963 or an average 



1/ Now Division of Biological Research, 

 Bureau of Commercial Fisheries. 



2/ Now Branch of Exploratory Fishing and 

 ~ Gear Research. 



