PREDATION ON ZEBRA MUSSELS (DREISSENA-POLYMORPHA) BY COMMON CARP (CYPRINUS-CARPIO)

We examined the gut contents of 31 common carp (Cyprinus carpio) colle cted at Mississippi River Mile 217 in August 1995 for evidence of pred ation on zebra mussels (Dreissena polymorpha). We found between 1 and 407 zebra mussel beaks in 83.9% of the fish we examined. For all fish examined, common carp contained 118.2 beaks per fish or about 59 zebra mussels per fish. The survey did not indicate that larger fish consum ed more zebra mussels than smaller fish. Estimated valve length for ze bra mussels consumed ranged from 1.48 to 42.52 mm with a mean 11.79 mm (SE = 0.10 mm). We found that larger fish tended to prey on larger ze bra mussels than did smaller fish. The general size range of zebra mus sels consumed by common carp overlapped the upper portion of the size range of young-of-the-year zebra mussels living at the site and the lo wer portion of the size range of older zebra mussels living at the sit e.