The majority of marine benthos has a planktonic phase in early life history, with a range of planktonic larval duration. Larval dispersal connects local adult populations, including self-seeding, and generates specific metapopulation structure. In recent years growing emphasis has been placed on the more prevalence of self-seeding than previously thought. One generally accepted definition of dispersal of larvae is their spread away from a source population to the settlement site. Thus a mean larval dispersal distance of a particular species would give a rough estimate of the metapopulation range. Although several compilations exist regarding dispersal distance, no measurement relevant to demography has been made. The concept of mean dispersal distance may be neither realistic nor heuristic. One promising approach to reveal the spatial configuration of a metapopulation would be to depict some appropriate setting with a few core local populations which are likely to be maintained by self-seeding. This presentation gives an example of a callianassid decapod shrimp distributed in waters extending from Ariake Sound, through Tachibana Bay, to an inner-shelf area of the East China Sea 10-20 km off Amakusa-Simoshima Island in mid-western Kyushu, Japan (shrimp adult habitat and larval duration = intertidal sandflats and 4 wk; water areal dimension = 30 km north-south and 50 km east-west).