Reproduction and early development in Haliotis coccoradiata (Vetigastropoda: Haliotidae)

Abstract

Reproduction and development of Haliotis coccoradiata, a small abalone endemic to southeast Australia, was investigated. The spawning season coincides with the warmer months of the year during the austral spring and summer. Spawning was artificially induced from September to February. By April the spawning season had finished coinciding with the presence of spent gonads in the population. The eggs of H. coccoradiata (mean diameter 175 μm) were smaller than those of other Haliotis species, although the size range of eggs released by individual females was broad (150–250 μm diameter). Early embryos had distinct regions of pigmented cytoplasm which marked the embryonic animal—vegetal axis. Early cleavage was typical spiralian and the trochophores hatched approxi-mately 18.5 h post-fertilization (hpf) at 20°C. By 21 hpf about 80% of larvae had shells. Overall the planktonic larval duration of H. coccoradiata is short, ca. 4–5 days, but some larva were still swimming on day 28 in the absence of coralline substratum. The presence of pigmented cytoplasm in vegetal blastomeres of the early embryos allows tracing of cell fates and the short development time of H. coccoradiata facilitates use of this species as a model organism for developmental biology.

Key words:

• Abalone
• spawning
• ontogeny
• ooplasmic segregation