Life cycle and effect of temperature,salinity on asexual reproduction of a rhizostome jellyfish scyphistoma, acromitus flagellatus (maas, 1903) under laboratory condition
Abstract:
The life cycle of a rhizostomae jellyfish, Acromitus flagellatus (Maas, 1903) and effect of temperature, salinityon asexual reproduction of its scyphistoma were studied under the laboratory condition. The life cycle of A. flagellatus revealed an alternation of reproduction between sexual reproduction in medusa stage and asexual reproduction in scyphistoma stage. The embryos developed into planulae within18-24 hours,4 daysold planula larvae settled on substrata to newly metamorphosed scyphistomae. Scyphistomae reproduced asexually viathe budding, stolon budding and cyst formation, and then developed into strobila (20 daysold larva) via Monodisk strobilation. Each strobila at 26 daysold released an ephyra which transformed to a small medusa (33 daysold larva). The bell diameter of small medusa was at least 6 mm. The study on effect of temperature and salinity onasexual reproduction of scyphistoma, A. flagellatus showed the highest number of buds (mean±SE) occurred at 25 °C and 20, 10 ppt (4.2±0.9, 3.8±0.7buds, respectively) (p0.05) by temperature and salinity