2019 Volume 73 Issue 2 Pages 75-83
Body size structure, abundance and gastropod shell use by the local population of the land hermit crab Coenobita brevimanus were investigated in the abandoned village of Amitori on Iriomote Island, Okinawa, Japan. Amitori was inhabited by a maximum of 200 people between the 17th century and 1971 and is now used as a research center of Tokai University. Results of mark-recapture experiments showed higher recapture rates than previous studies and an estimated population size of > 1000 crabs. The hermit crabs in Amitori, which use shells of edible marine gastropods such as Turbo (Marmarostoma) argyrostomus likely discarded by the former residents, grow to be larger than crabs living on an adjacent uninhabited island and an inhabited village without shell middens. The proportion of abraded and broken shells used by the crabs in Amitori is higher than that of crabs in another village on an adjacent island where edible gastropod shells continue to be discarded by residents. The crabs in Amitori use either small shells with little damage, or relatively large shells with more damage. Since the growth and abundance of C. brevimanus individuals depend on the continued supply of new marine gastropod shells, the proportion of large crabs in the uninhabited village of Amitori will likely decrease in the future.
