rearing areas and to the configuration of the hydrography of 

 the sea. 



Our next problem was to define this area of mixing for 

 the three important species of salmon: red, pink and chum 

 {0. keta) salmon. Tagging experiments provided the best way 

 to define these areas, and such investigations were arranged 

 by contract with the Fisheries Research Institute of the 

 University of Washington, 



Finally, to answer the problem set forth in the Protocol, 

 we must know not only where salmon are, but also the rela- 

 tive abundance of North American salmon at any point on the 

 high seas. The answer to this question required the develop- 

 ment of new methods for identifying Asian and North Ameri- 

 can fish. In effect, we must examine a salmon, and by certain 

 differences, such as variations in size, shape, or numbers 

 of parts in various sections of the body, be able to say that 

 this fish is from Asia or from North America, Three suc- 

 cessfxil methods for identifying stocks of salmon are now 

 being used. 



These areas of the North Pacific Ocean mentioned above 

 were all fished by our research vessels for the purpose of 

 securing samples to determine where fish in the high seas 

 originated. In studying these fish samples, examination of 

 the structure of scales of individual fish was the first 

 approach followed. It has been found that salmon tend to 

 deposit rings (or circvili) on their scales in patterns charac- 

 teristic for each area, A careful study of these characters 

 of red salmon scales demonstrated by 1957 that Bristol Bay 

 red salmon were fovind far to the west in the central Pacific, 

 Subsequently, we have devised means of making quantitative 

 separations into continent of origin of scale ssmnples taken 

 on the high seas. 



Similarly, we have experienced considerable success in 

 the study of the coxints of body structures of salmon. This 

 different approach makes use of variations in the number of 

 scales on the fish, bones in the backbone, bones in the gill 

 arches, and fin rays, as well as a number of other readily- 

 examined portions of the fish which tend to show differences. 

 This method has been particularly useful to us in developing 

 quantitative separation of red salmon on the high seas. We 

 have been able to determine with reasonable precision what 

 portion of the salmon in a sample taken in the middle of the 

 ocean came from North America and what portion Ceime 

 from Asia, 



One of the newer and more fascinating approaches, or 

 techniques, applied is that of serological or blood chemistry 

 differences between Asian and North American fish. It has 

 been necessary to develop this research from a rather 

 scanty basis of knowledge of blood types in fish. However, it 

 has been found that salmon and other fishes do indeed have 

 blood types. It has been possible to produce antisera which 

 will react with the blood of North American red salmon but 

 will not react with the blood of Asian red salmon. By this 

 means it is possible to collect samples of blood on the high 



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