Abstract
Perna mussels have been introduced into Japanese waters since 1967. We investigated the occurrence and wintering of the Perna mussels in Ise and Mikawa Bays, central Japan. Most of specimens collected in the bays are identical with Perna viridis, but several specimens were difficult to identify to a specific level based on the past taxonomical studies. It is difficult to identify the specimens of the Perna mussels introduced into Japanese waters where commercial vessels have often come from oversea. Several specimens of P. viridis and Perna spp. were wintering at Nagoya port located in the innermost of Ise Bay and also at cooling water discharge of the Thermal Power Plant in Hekinan city located in Mikawa Bay.
