purse seines were developed for capturing salmon in the 

 open sea in good condition for tagging. Brailing nets and 

 holding tanks were designed for handling salmon with mini- 

 mvim injury. Experiments were needed to find tags that would 

 give maxim\am returns after 1 or 2 years on rapidly- growing 

 fish. Identification of the several species of salmon, not 

 normally a problem in coastal areas where fish are mature, 

 was a problem at sea. Catches often included all five species 

 and many age groups. Rapid identification of the younger 

 fish sometimes only 8 to 10 inches long required practice. 

 Sccde samples were taken from all fish tagged for later 

 positive identification. A toted of 48,296 salmon and steelhead 

 have been tagged over the 5 years, and 1,128 have been 

 returned to date. The overall rate of return (2,3 percent) 

 is based on all salmon tagged, including immatures, which 

 of course yield fewer returns than matures. Returns of 

 mature salmon, those destined to spawn in the year of 

 tagging, average nearly 10 percent, Immatures may spawn 

 1, 2, or 3 years later, and some of those still at liberty will 

 be recovered in I960 and 1961, Returns from centrad Pacific 

 experiments have come from Japan, the U.S.S.R. , Alaska, 

 Canada, Washington, Oregon, and Idaho, and from the Japa- 

 nese high seas gill net fishery in the North Pacific Ocean 

 and Bering Sea. 



Each year, results of tagging have disclosed new and 

 valuable data on ocean habits and movements of salmon. 

 The abxindance and migration patterns of the several species 

 have been fovind to vary tremendously from year to year, so 

 that continued observations are needed to answer fully the 

 questions implicit in the North Pacific Treaty. 



A sximmary of resxilts to date for all species is presented 

 in figures 5 to 8, Tagging areas are shown by circles, and 

 recovery locations by arrowheads. The thickness of lines 

 indicates approximate relative numbers of fish to a given 

 destination. Liines are not intended to show exact routes, but 

 are drawn diagrajumatically for simplicity. Fish are shown 

 moving westward prior to going through Aleutian passes 

 because purse- seine catches indicated a positive westward 

 movement through tagging areas south of the Aleutians. In 

 evaluating the four figures, it must be borne in nriind that 

 most tagging was in the areas along the Aleutians from 160^ 

 West to 170*^ East longitude. Mature salmon, of course, are 

 recovered only in the year of tagging, while immatures are 

 recovered 1 or 2 years later (except for some few immatures 

 which were taken by the Japanese high seas gear in the year 

 of tagging). Since tagging was conducted at numerous loca- 

 tions each year from May to September, returns may be 

 considered representative of summer stocks in the Aleutian 

 area. 



Red salmon returns (fig. 5) indicate the overwhelming 

 predominance of American red salmon along the entire 

 Aleutian Chain in the North Pacific and Bering Sea. A total 

 of 215 was returned from Bristol Bay, but only one from 

 Asia. The destingation of a few others is uncertain. The 



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