Mortality was low until the 5th month for both species, with similar values being recorded for the control and treated bivalves: 5.6% in control (natural pH conditions) and 5.5% in treated (pH 7.4)
mussels, 1.1% in control and 1.7% in treated clams. A large increase in mortality was only observed at the end of the experiment, mostly in treated animals. Cumulative mortality was significantly higher in treated bivalves with respect to controls, with a sensibly higher difference being observed in clams (39%) than in mussels (11%)