Estimation of the survival rate of white-spotted charr Salvelinus leucomaenis in a fishing prohibited section of the Chigonosawa Stream, a tributary of the Kiso River in central Japan was attempted from data reading from figures of the published literature and a table of the unpublished literature which recorded the changes of fish number from eggs. The unpublished literature was written by the same author who wrote the published literature, and is considered to be based on the same data set.

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... g and fish numbers in age-0 summer, age-1 summer, age-2 summer and age-3 summer of each of 1963 -1973 year-classes were read from the figures recorded in the published literature using image processing software. Then, those data were compared with the egg and fish numbers recorded in the table of unpublished literature. The coincidence rate between the two data sets was high and differences were little even though two data were not coincident. So, reliability of the data read from the figures of published literature seemed to be high. Approximate survival rates of the charr from eggs to age-0 summer, age-1 summer, age-2 summer and age-3 summer were 5%, 2%, 1%, 0.1%, respectively.