Induction of metamorphosis of pediveliger larvae of the mussel Mytilus galloprovincialis Lamarck, 1819 using neuroactive compounds, KCl, NH₄Cl and organic solvents

Abstract

Pediveliger larvae of Mytilus galloprovincialis were subjected to a series of bioassays to investigate the induction of metamorphosis using neuroactive compounds, K⁺, NH₄ ⁺ and organic solvents. Growth and survival of post-larvae obtained using ethanol and methanol were also observed. Epinephrine, phenylephrine, clonidine and metanephrine induced larval metamorphosis at 10⁻⁶ to 10⁻⁴ M in both 24-h and continuous exposure assays. In 24-h exposure assays, α-methyldopa at 5×10⁻⁵ M and methoxyphenamine at 5×10⁻⁵−10⁻⁴ M induced 55−94% metamorphosis. Similarly, excess K⁺ at 3×10⁻² M induced 39% metamorphosis and NH₄ ⁺ at 1−5×10⁻² M induced 63–78% metamorphosis. The EC50s of seven organic solvents ranged from 0.04 to 0.82 M. Post-larvae that metamorphosed using ethanol and methanol survived as juveniles and grew at the same rate as those from microbial biofilm. Thus, the above compounds can be useful inducers of metamorphosis for antifouling studies using larvae and juveniles of M. galloprovincialis.

Keywords:

• Mytilus galloprovincialis
• larval metamorphosis
• artificial inducers
• adrenergic agonists
• organic solvents
• antifouling

Acknowledgements

The authors are grateful to the Nagasaki Prefectural Institute of Fisheries for their cooperation in the collection of adult mussels. The authors wish to thank Mr N. Ogura and Mr S. Miyazaki (Nagasaki University) for technical assistance. All experiments complied with the current Japanese laws.