Intraspecific differences in erythrocyte antigens (blood types) were shown to occur in four species of Pacific salmon, the sockeye or red salmon (Oncorhynchus nerka), the chinook or king salmon (0. tshawytscha), the chum salmon (O. keta), and the pink salmon (O. gorbuscha). Antisalmon-erythrocyte sera prepared in rabbits and chickens were used after absorption of species-specific antibodies. Some of these blood types were shown to differ in their frequency of occurrence between different geographic races. In addition, isoimmunizations were conducted on one race of sockeye salmon. Antisera of seven different specificities were prepared and at least eight different patterns of antigenic composition were displayed by the cells tested.
These results indicate that considerable antigenic diversity exists in salmon. Reagents to detect valuable markers for the investigation of geographic races of salmon should be obtained through further research.