Monitoring the Reproduction and Development of Eggs in the Sea Hare Aplysia fasciata under Laboratory Conditions

Abstract

This study looks at spawning patterns, egg mass shape, and embryo development to learn more about the reproductive biology of the A. fasciata species that lives in Libya's coastal waters. In June 2022, eight mature Aplysia fasciata collected from Tajura coast and kept into aquarium contain aerated seawater and marine algae (Ulva lactuca). After five days, a mating couple was seen in the aquarium, and, a mass of fertilized eggs were produced. The clusters eggs were transfer to new aquarium. After few hours, the eggs started development to embryo and at 10 day the egg masses colour changed to a brownish as the embryo developed to the trochophore stage and started to rotate inside capsules. After 16 day of spawning the trochophore broke the egg capsules to hatch as free swimming larvae (the veliger stage). Unfortunately, after 25 day of fertilized eggs all larvae died as veliger. Probably, the result of inadequate conditions for rearing or lack an availability of appropriate food. Whereas A. fasciata has never been recorded before in the Libyan waters.