Radioisotope Marking Methods of Fish and the Public Health Consideration

Marking or tagging experiments have become importart in recent years to study the migration of fish, effect of artificiai liberation, and the population of fish in a certain water area. The two types of marking of fish by radioisotopes which were employed since 1954 are described. One is an abdominal insertion of a coated Co/sup 60/ pin, 0.1 to 1 mc to each individual of fish. The other is a radioisotope contamination of fish by either oral ingestion or muscular injection or uptake through gill. The radioisotope used was Zn/sup 65/, 0.1 mu c per individual of fish in average. The effetive half life of Zn/sup 65/ in fish is found to be 12 days. Dringing water contamination from the fish which had been liberated, and unexpected catch of radioactive fish by people are considered from standpoint of radiation public health. (auth)