Comparative Response of the Zebra Mussel, Dreissena polymorpha, and the Asian clam, Corbicula fluminea, to DGH/QUAT, a Nonoxidizing Molluscicide

In a series of laboratory and field experiments, zebra mussels,  Dreissena polymorpha , and Asian clams,  Corbicula fluminea , were exposed to the cationic surfactant-based molluscicide DGH/QUAT under both static and flow-through conditions. Cumulative mortality of the two bivalves was comparable after 24-h treatments, but zebra mussels experienced significantly higher mortality in 6-h exposures conducted at 20–25 °C. The rate at which mortality occurred was greater for the zebra mussel in all experiments. The molluscicide induced an increase in tissue water and a decrease in whole body glycogen levels of both organisms, although these changes occurred at a faster rate in the zebra mussel. While greater sensitivity of zebra mussels to DGH/QUAT may have been due to a longer time spent siphoning during the exposure periods, it may also indicate an enhanced ability of the Asian clam to tolerate the biochemical stress associated with exposure.