Instantaneous effect of dibromomethane on metamorphosis of larvae of the sea urchins Strongylocentrotus nudus and Strongylocentrotus intermedius

A volatile chemical, dibromomethane (DBM), produced from red coralline algae is known as a chemical inducer of larval metamorphosis of the sea urchin Strongylocentrotus nudus. We performed experiments exposing DBM to the larvae of S. nudus and Strongylocentrotus intermedius through a hydrophobic membrane. Metamorphic rates resulting from different diluted DBM solutions and exposure times were ascertained. The highest metamorphic rate, more than 80% in both species, was found after 1 h exposure to 1/2 diluted DBM. With this dilution, more than 80% of S. nudus and S. intermedius larvae metamorphosed 1 h after start of the experiment after only 10 and 5 min exposure, respectively, which corresponded to the low concentrations of 52–61 ppm and 34–43 ppm DBM by GCMS analysis, respectively. These findings suggest that DBM has an instantaneous effect on high success of metamorphosis of larvae of S. nudus and S. intermedius.