| An effective treatment using catochalasin B (1 mg CB/ml dimethylsulfoxyde in 1 litre of sea water) was developed to induce triploidy in the Manila clam Ruditapes philippinurum (Adams and Reeve). The percentage of induced triploidy was assessed by karyological examination of embryos and spat. The treatment was found to be optimal between 20 to 35 minutes post-insemination exposure to CB, at 25'C, and produced 75.8 ± 5.7% triploid embryos on the average over four experiments. Growth and survival of larvae to metamorphosis were recorded for two different rearings each split into two replicates. Both larval rearings showed similar survival up to settlement: 19.3 and 27.0%, on average over two replicates, in the treated batches relative to the controls. Mean... |
