Differences in the biochemical compositions of two dietary jellyfish species and their effects on the growth and survival of Ibacus novemdentatus phyllosomas

Phyllosomas (planktonic larvae) of slipper lobsters cling onto and feed on jellyfish under both natural and laboratory conditions. Phyllosomas of Ibacus novemdentatus are capable of feeding on various jellyfish species including venomous stingers; however, the range of jellyfish species capable of supporting the growth and survival of phyllosomas is unknown. Seventeen (12 for the first and five for the second trials) and 18 (13 for the first and five for the second trials) phyllosomas were fed exclusively on the jellyfish Aurelia aurita and Chrysaora pacifica, respectively. Aurelia aurita-fed phyllosomas metamorphosed into the nisto stage (postbenthic larvae) approximate to 54days after hatching, whereas C.pacifica-fed phyllosomas did not. Major nutritional compositions such as amino acids, fatty acids and minerals were compared between the two jellyfish species. The proportion of each major nutritional component was not significantly different between the two jellyfish species, suggesting that C.pacifica was not nutritionally inferior to A.aurita. Therefore, the observation that the C.pacifica-fed phyllosomas did not metamorphose into the nisto stagewas not because of major nutritional compositions but due to other factors such as the lack or excess of other minor nutrients, or the species-specific texture of the jellyfish.