Abstract / Introduction / Summary:
The surveys were conducted at the lower reaches of four rivers; Ohse R., Kametoku R., Shimoda R. and Minato R., in Tokunoshima Island to clarify the fresh- water crustacean decapod fauna in May and September 2020. All shrimp-species and two crab-species cap- tured, i.e. Paratya compressa, Caridina serratirostris, C. leucosticta, C. typus, Palaemon pacificus, P. serrif- er, Macrobrachium formosense, M. japonicum, Pty- chognathus ishii and Deiratonotus japonicus, had their ovigerous females during the survey periods. We dis- cussed the minimum carapace length of the ovigerous females of each species. Maine size group of oviger- ous females were also discussed in each species. Pty- chognathus ishii had lots of ovegerous females, while the related species, P. barbatus, had no ovigerous fe- male in May and September.