Establishment of the exotic turtle Mauremys mutica in the Inbanuma basin, Chiba prefecture

Abstract

During a survey of the freshwater turtles in the Inbanuma basin, central Japan, Asian brown pond turtles Mauremys mutica were recorded at 6 of 50 sampling sites from 2000 to 2004. Of a total of 32 turtles collected, 29 were captured within a 2.5 km section of the Takasaki Stream. Ten juvenile turtles presumed to have hatched in the wild were also captured. Based on these records, we suggest that M. mutica has established an incipient population in this area. Examination of morphological characters indicates that the Inbanuma population of M. mutica is a mixture of two subspecies from various localities.