A NOTE ON THE INTERMEDIATE HOSTS OF THE TREMATODE, CREPIDOSTOMUM COOPERI HOPKINS, 1931, PARASITIC IN SPECKLED TROUT (SALVELINUS FONTINALIS (MITCHILL)) IN SOME LAKES AND RIVERS OF THE QUEBEC LAURENTIDE PARK

Abstract

In some areas of the Quebec Laurentide Park the developing larval stages of the trematode Crepidostomum cooperi were found in sphaeriid clams of the genus Pisidium (P. subtruncatum, P. compressum, P. adbitum, P. llijeborgi, and P. nitidum), and the encysted state in nymphs of the mayfly Hexagenia recurvata and in those of another species of mayfly of the genus Polymitarcys. These constitute new records of intermediate hosts for C. cooperi. Sexually mature worms were recovered from trout three to four weeks after the trout fed upon infected mayfly nymphs, thus confirming Hopkins' observation on the length of time required by the worm to attain sexual maturity.