A SETTLEMENT INHIBITION ASSAY WITH CYPRID LARVAE OF THE BARNACLE BALANUS-AMPHITRITE

A settlement inhibition assay using barnacle cyprid larvae, Balanus am phitrite, was developed with Cd2+ and phenol as standard reference tox icants. Mean percentage settlement of cyprid larvae showed a progressi ve reduction with increasing concentrations of Cd2+ and phenol. A sign ificant reduction in settlement was found when cyprids were exposed to 0.1 mgL(-1) Cd2+ or 10 mgL(-1) phenol. The assay was used to assess t he sublethal toxicity of three oil dispersants (Vecom B-1425 GL, Norch em OSD-570 and Corexit 9905) commonly used in Hong Kong waters. Result s of this investigation show that the barnacle settlement inhibition a ssay can be incorporated into the battery of tests currently available for ecotoxicological assessment of marine contaminants. (C) 1997 Else vier Science Ltd.