Species composition and body size of Macro brachium prawns caught using funnel traps during the fishing season in the downstream freshwatersof the dhimanto River

摘要

To obtain information regarding the catch of Macrobrachium prawns in the Shimanto River, Kochi Prefecture, Japan, the species composition and body size of Macrobrachium prawns caught using funnel traps were investigated at St.1and St. 2 (11km and 28 km upstream from the river mouth, respectively). Most of the catch comprised M. formosense, followed by M japonicum with very less catch of M. nipponense. The body size of M. formosense and M japonicum at St. 2 was larger than that at St.1.The proportionof males of these two species was high at both the stations, accounting for 76-92% of M. formosense and 67-77% of M japonicum.