Matteson (1948) in studying the species’ life history in the mid 1940’s, transported mussels from Ocqueoc River and Ocqueoc Lake to Douglas Lake and placed them in shallow water near shore to serve as a storage population and stock for experimentation. He states that some clams stored over the winter moved into deeper water with the return of warmer weather and became scattered and difficult to retrieve. Evidently the small population of E. complanatus accidentally released is maintaining itself along the sandy, wave swept shoal areas of the eastern and southeastern shores of Douglas Lake. Perca flavescens, the yellow perch, has been found to serve as a glochidial host. Matteson found that only yellow perch, obtained in Douglas Lake, became infected with glochidia and served as a natural host. It was somewhat surprising on the basis of distribution to find two specimens of E. complanatus in Douglas Lake (Cheboygan County) in August, 1968 and two in August, 1969. Furthermore, Dr. W. Fennel found one specimen in early August, 1969. The nearest occurrence of E. complanatus is from Ocqueoc River and Lake, approximately 25 miles to the east.