EFFECTS OF DISSOLVED MERCURY ON EMBRYOGENESIS, SURVIVAL AND GROWTH OFMYTILUS-GALLOPROVINCIALIS MUSSEL LARVAE

The effects of Hg concentrations ranging from 0 (control) to 1024 mu g l(-1) upon embryogenesis, survival and growth of Mytilus galloprovinc ialis mussel larvae were investigated. Embryogenesis was abnormal in 5 0% of the individuals at 10 mu g l(-1). The 48 h LC(50) for D-shaped, early umbonate, late umbonate and eyed larvae were 51, 164, 322 and 38 3 pg l(-1) respectively. The LC(50) was an allometric function of ash- free dry weight with exponent b = 0.60. Larval growth was significantl y reduced after 6 d exposure to 4 mu g Hg l(-1) and after 10 d exposur e to 2 mu g l(-1). No significant differences in lethal or sublethal s ensitivity to Hg were found between M. galloprovincialis and previousl y studied Crassostrea gigas embryos and larvae. The implications of th ese findings for monitoring pollution by utilising different bivalve s pecies are discussed.