Optimal sperm concentration and time for fertilization of the tropical abalone, Haliotis asinina Linné 1758

Abstract

Current interest in the tropical abalone, Haliotis asinina has generated research into seed production and culture techniques. However, there has been no report regarding the optimal sperm concentration for fertilization and development, and gamete viability for this species. Spawned eggs of H. asinina were artificially fertilized using eleven final sperm concentrations ranging from 1×10² to 1×10⁷ sperm ml⁻¹. In another experiment, eggs were fertilized using sperm spawned at the same time at a final sperm concentration of 1×10⁵ sperm ml⁻¹ at 1, 2, 3, 4, and 5 h after spawning. Sperm concentrations of 5×10³ to 1×10⁵ sperm ml⁻¹ gave both maximal fertilization rate and normal trochophore development. The sperm to oocyte ratio of this range is 1×10³ to 2×10⁴. Gametes were still viable 2 h after spawning; both fertilization and normal development rates decreased when fertilized later. It is recommended to use 1×10⁵ sperm ml⁻¹ for artificial fertilization of H. asinina eggs within 2 h after spawning.