TSUTSUMI, HIROAKI and MASAO TANAKA (Amakusa Marine Biological Laboratory, Faculty of Science, Kyushu University). 1987. A new method for measurementof body size and analysis of generation structure of population, using a microcomputer. Benthos Research (Bull. Jap. Assoc. Benthology), 31 : 18-28.
Effective methods for the quantitative study of polychaete population dynamics are noted and a new method using a microcomputer to analyse the generation structure of populations is introduced. For the population study of the animals without age characters such as polychaetes, the resolution of polymodal size-frequency distribution of population is the only way to estimate the generation structure of the population and some population parameters. Over the last decade, we have devised a series of programs for the microcomputer to analyse the generation structure of population from the size-frequency distribution. The body size of worms is measured with a digitizer connected to a computer, and the frequency of each size class is automatically counted. Using a program for a modified graphic method, the polymodal size-frequency distribution of the population is resolved to monomodal ones. The program for the graphic method is explained with an example.